text:
Today, the domestic benchmarks closed on a negative note for the third straight session as weak cues from the Asian markets weighed on sentiment. The Metal and Banking space led the decline.
BSE SENSEX closed at 15727.85 down by 146.1 points or by 0.92 % and then NSE Nifty ended at 4705.8 down by 44.7 points or by 0.94 %.The BSE MIDCAP closed at 5137.18 down by 55.18 points or by 1.06 %, while the BSE SMLCAP ended at 5586.55 down by 63.47 points or by 1.12 %.The BSE Sensex touched intraday high of 15887.8 and intraday low of 15666.46 The NSE Nifty touched intraday high of 4756.2 and intraday low of 4685.65.
The positive closing of the US markets on Tuesday had little impact on domestic sentiment during morning trade. On Tuesday, the Nasdaq closed at 2625.2, gaining 6.56 points over the previous day"s closing and the S&P 500 gained .10 points and closed at 1265.4. The Dow Jones Industrial lost 2.65 points and closed at 12291.05. Soon after witnessing a gap down opening, the domestic benchmarks slipped further amid weak cues from the Asian markets. Most of the Asian markets were trading lower on Wednesday after a report said that industrial production in Japan contracted in November 2011, compared to the previous month as overseas demand weakened, while consumer spending in the country fell for the ninth straight month in November 2011. Moreover, a larger than expected drop in US home prices in October 2011 also weighed on sentiment. US house prices fell by 3.4 per cent in October 2011, year on yea r, a sign that a housing market recovery remains far way. Moreover, investors were also wary of taking fresh positions in stocks with the year soon coming to an end. The benchmarks continued to trade on a subdued note in then negative terrain amid weak global cues. The benchmarks fell to the day"s low in afternoon trade as profit booking ahead of the expiry of derivative contracts for December 2011 due on Thursday weighed heavy. The benchmarks continued to trade lackluster in the final three hours of the trading session. Finally, the domestic benchmarks ended on a bearish note, with the BSE Sensex and the NSE Nifty shedding over 0.90% each. Among the BSE Sectoral indices, BSE Metal and BSE Bankex lost 2.05% and 1.98% respectively.
Among the 30 Sensex stocks, Jindal Steel & Power, ICICI Bank, Hindalco Industries, Mahindra & Mahindra and Wipro closed lower by 7.07%, 3.88%, 2.51%, 2.39% and 2.27% respectively. Among the Sensex stocks, there were 12 advances and 18 declines. On BSE out of total shares traded 2896, shares advanced were 1065 while 1711 shares declined and 120 were unchanged.
On the economic front, the Indian government said on Tuesday that bilateral trade between Japan and India is likely to reach USD 25 billion by 2014, up from USD 15 billion in 2010.
On the global front, industrial production in Japan contracted in November 2011, compared to the previous month as overseas demand weakened amid a stronger yen and the lingering debt crises in Europe, said a report by the Ministry of Economy, Trade and Industry on Wednesday. Japan"s industrial output fell by 2.6 per cent in November 2011, compared to the previous month.
On the Asian front, Shanghai Composite closed up 0.18%, Hang Seng ended down 0.59% and Nikkei 225 closed down 0.20% on Wednesday.
On the European front, CAC40 was up 0.58%, DAX was trading higher by 0.14% and FTSE100 was up 0.66% on Wednesday.
On the Corporate front, Punj Lloyd said on Wednesday that it has bagged a Rs 1,050 crore highway project from GMR Projects Private Limited. The stock of Punj Lloyd closed down 0.97% at Rs 40.90 on the BSE.


text:
OTTAWA (Reuters) - Canadian Finance Minister Jim Flaherty said on Thursday he expected his stimulus package to be passed by the Senate promptly, saying officials were working "on an urgent basis" to make sure money gets spent right away.
The House of Commons passed the bill late on Wednesday.
"(The bill) is in the Senate now. I'm encouraged from what I've heard in the last 24 hours that the Senate may deal with it expeditiously. I'm hopeful that will happen," he said in televised remarks from Washington after a meeting with White House economic aide Larry Summers.
Reporting by Louise Egan; editing by Rob Wilson

subset: commoncrawl


text:
Marco Polo Marine Ltd. (the Company) referred Monday to the Company's announcements dated Nov. 17 and Nov. 24 with respect to the termination of the $214.3 million rig construction contract dated Feb. 26, 2014 (as amended and supplemented) entered into between Marco Polo Drilling (I) Pte. Ltd. (MP Drilling) with PPL Shipyard Pte Ltd. (PPL) for the construction of a high-specification jackup (the New Rig) -- PPL Jackup TBN 1 (400' ILC) -- based on PPL's proprietary Pacific Class 400 design (the Rig Construction Contract).
Unless otherwise defined herein, capitalized terms and expressions used in this announcement shall bear the same meanings ascribed to them in the Company's announcements dated Feb. 26, 2014, Nov. 17 and Nov. 24 in relation to the Rig Construction Contract. Copies of these announcements can be found at the official website of The Singapore Exchange (www.sgx.com).
On Nov. 17, MP Drilling had issued PPL, the builder of the New Rig, a notice of termination of the Rig Construction Contract following the latter's failure to comply with certain of its material contractual obligations. In arriving at this decision to terminate the Rig Construction Contract, MP Drilling has taken into account various factors including cracks found on all three legs of the New Rig during two rounds of tests, notwithstanding repair works carried out by PPL after the first round of tests.
In view of this termination, MP Drilling had informed PPL that it would not be taking delivery of the New Rig. In addition, it is seeking, among others, a refund from PPL of the initial amount of 10 percent of the contract price (approximately $21.4 million) as well as all other payments made by MP Drilling under the Rig Construction Contract (collectively, Initial Payment) previously made to PPL pursuant to the Rig Construction Contract together with interest.
MP Drilling disagrees with the allegations in the announcements made by Sembcorp Marine on Nov.18 and Nov. 25 that, among others, MP Drilling is in alleged repudiatory breach of the Contract or that MP Drilling's termination of the Contract is wrongful.
The second announcement by Sembcorp Marine on Nov. 25 states that the New Rig is at "the final phase of construction" and does not deny the existence of defects found on all three legs of the New Rig during two rounds of tests as set out in MP Drilling's announcements dated Nov. 17 and Nov. 24. MP Drilling regards the nature and number of cracks and other defects (such as porosity) found on all three legs of the New Rig at this stage of construction wholly unacceptable:
MP Drilling maintains therefore that it is entitled to terminate the Contract. The consequence of termination is that MP Drilling is discharged from its obligations under the Rig Construction Contract and is under no further obligation to perform the same. This includes a discharge of its obligation to make any further payment of the contract price or any other sum under the Contract to PPL.
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text:
LisaS: I see myself as stagnating. I know there are authors who find their "schtick" and can go for years on it. I think of greats like Mary Higgins Clark, Agatha Christie. But I just can't sit still. I need to really push myself and want to grow.
BradW: I like that idea. What do you think an MFA has to offer you?
LisaS: A wider picture. I've never learned the possibilities of writing. What I've got I've learned on my own by trial and error. I need to look outside myself in the writing world.
BradW: How many books on writing have you read so far?
LisaS: Two. I think. I can only think of one, but I'm giving myself the benefit of the doubt! It's called "Making Shapely Fiction," by Jerome Stern. Is that pathetic or is that pathetic?
BradW: Oh wow! Two? I wish I had achieved my level of writing by sheer talent like you seem to have. I'm at the other extreme. I've read dozens of books on writing. In the last 6 months I've probably read 4 or 5. You didn't read "Bird by Bird?"
LisaS: Nope. I did read "Traveling Mercies," though. Does that count?
BradW: I won't tell anybody you said that. You'll be stoned.
LisaS: Oh tell them. It cracks me up the way Anne Lamott. She is so revered. She's pro-Democrat, pro-choice, pro-homosexuality, and the Evangelicals lap her up. It's pretty amazing. And yet I can hardly get away with the word "crap."
BradW: Hell no you can't! I read "Bird by Bird" this year, finally. Heard so much about it, I had to find out what the hype was about.
LisaS: What did you think of the book, by the way?
BradW: "Bird by Bird" is a good book, but it wasn't for me. I'm not as neurotic as she is. But it has good advice for neurotic, conflicted writers.
LisaS: Yeah. I've always thought myself pretty neurotic, but she sometimes makes me scratch my head. But I am glad she's been accepted by the Evangelical community. It's a good thing.
BradW: On the book signing tour for "Welcome to Fred," my editor and Rick Lewis, the Logos Bookstore owner in Dallas, were talking about Anne and I had no clue who she was. They just stared at me. So, finally 3 years later, I read the book. I'm a busy guy. It takes me awhile to get around to things.
LisaS: Me too. Only I'm a gal.
BradW: So I hear. Speaking of which, I have a pet peeve to share.
LisaS: Oh cool.
BradW: I keep hearing wannabe writers talking about "putting butt in chair" and "putting in the time at the keyboard" like it's some chore. What's up with that?
LisaS: Oh, it's a major chore for me! Sometimes I hate writing with a passion! I think, "Fotomat's got to be better than this!" (Are there Fotomats any more?)
BradW: Ha! Not my perspective at all. When I read those things, I think, "If you don't like writing, then don't do it! There are plenty of us who like to put our fat butts in that chair and write away. If it's such a chore, then why bother?"
LisaS: It's like Flannery O'Connor said. "Because I'm good at it." (Not that I'm a Flannery, by golly!)
BradW: Heh.
LisaS: You're lucky. What's it like to be a writer that loves to write?
BradW: It is wonderful to be a writer who loves to write! It would be even better if this bothersome day job didn't keep me from doing it more!
LisaS: And it really does beat the 9-5 at an office.
BradW: Well, I have both.
LisaS: Lucky you, eh?
BradW: Actually, I don't, because my day job is waaay more than 9 to 5.
LisaS: I know. For the reading audience's benefit: you're in Singapore right now, right?
BradW: Yep. I have a 7am flight tomorrow. Which means a 4am cab ride.
LisaS: Oh good grief. What time will you get home?
BradW: Tomorrow I'm flying to Tokyo. I'll be there 2 days, and then I'll fly back to Honolulu. Let me tell you my travel schedule the last 9 weeks.
LisaS: Please do!
BradW: 1. Portland, OR. 2. Boston, MA. 3. Honolulu, HI (home). 4. Madrid, Spain. 5. Paris, France / Munich, Germany. 6. Geneva, Switzerland. 7. Honolulu, HI. 8. Taipei, Taiwan. 9. Singapore / Tokyo, Japan. Then I get to go home for a week or two.
LisaS: Amazing.
BradW: Very little writing done in the last 2 months.
LisaS: I'll bet.
BradW: But lots of research.
LisaS: And that sure counts!
BradW: How much do you have to work at time management when you're on a deadline?
LisaS: Nowadays, I just have to carve out the time and stick to it. And I get this real pushy feeling in my stomach that just has to finish because I'm so sick of the project. I think, "Get this thing offa my plate, I can't stand looking at it anymore!"
BradW: Not because of the deadline, but because you get weary of the project?
LisaS: Well, funny thing. Usually the two coincide. Must be a deep psychological response!
BradW: Aha.
LisaS: How about you?
BradW: I like writing and I like editing, so I don't really get sick of it. But once I feel like I'm done, then I'm done. At that point I want to put the bow on it, call it finished and move on.
LisaS: Amen. I love starting a new project.
BradW: Speaking of new projects, I see you have a full plate ahead of you. What's up with that over commitment thing?
Conclusion Tomorrow, followed by a review of Robert Liparulo's, Comes a Horseman (and discussion).


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I loved Nature's Classroom! It was so much fun, but my favorite part was at the end of the day when we all did a sing-along in the amphitheater (my favorite song was the one about the worm). The food we got was great; it had amazing gluten-free options (I'm gluten free), and really good tasting gluten-free bread. I really liked my counselor Sassafras (all the counselors had nicknames, I still do not know my counselor's actual name). The only problem was that whenever I came back to my bunk, I would find weird grains of sand in it that I had to sweep off my bed. Also, I think it would have been a lot easier to get to the top bunk with a ladder and not by climbing on the bed frame.
I really enjoyed the simulations we did there, and my favorite was the Oregon Trail one. In the Oregon Trail, my group were farmers and we had the least amount of money, but for some reason the person who was in charge of buying the wagon we would be using decided to buy the Mercedes of wagons (it was a lot of money). In a nutshell we all froze to death in the end in the simulation. Nevertheless I had an amazing time at Nature's Classroom.
Picture by PDS.


text:
|Publication number
|Publication type
|Application number
|Publication date
|May 13, 2003
|Filing date
|May 21, 1999
|Priority date
|May 21, 1999
|Fee status
|Also published as
|Publication number
|Thomas D. Stephens, Mark A. Kelty, Alistair J. Price
|Original Assignee
|Corvis Corporation
|Export Citation
|BiBTeX, EndNote, RefMan
|Patent Citations (41), Non-Patent Citations (20), Referenced by (28), Classifications (23), Legal Events (7)
|External Links: USPTO, USPTO Assignment, Espacenet
Not Applicable
Not Applicable
The present invention is directed generally to optical transmission systems. More particularly, the invention relates to controlling optical signal characteristics in optical links including links containing optical amplifiers, such as erbium doped fiber amplifiers ("EDFAs").
Digital technology has provided electronic access to vast amounts of information. The increased access has driven demand for faster and higher capacity electronic information processing equipment (computers) and transmission networks and systems to link the processing equipment.
In response to this demand, communications service providers have turned to optical communication systems, which have the capability to provide substantially larger information bandwidth transmission capacities than traditional electrical communication systems. Information can be transported through optical systems in audio, video, data, or other signal formats analogous to electrical systems. Likewise, optical systems can be used in telephone, cable television, LAN, WAN, and MAN systems, as well as other communication systems.
Early optical transmission systems, known as space division multiplex (SDM) systems, transmitted one information signal using a single wavelength in separate waveguides, i.e. fiber optic strand. The transmission capacity of optical systems was increased by time division multiplexing (TDM) multiple low bit rate, information signals into a higher bit rate signals that can be transported on a single optical wavelength. The low bit rate information carried by the TDM optical signal can then be separated from the higher bit rate signal following transmission through the optical system.
The continued growth in traditional communications systems and the emergence of the Internet as a means for accessing data has further accelerated the demand for higher capacity communications networks. Telecommunications service providers, in particular, have looked to wavelength division multiplexing (WDM) to further increase the capacity of their existing systems.
In WDM transmission systems, pluralities of distinct TDM or SDM information signals are carried using electromagnetic waves having different wavelengths in the optical spectrum, i.e., far-UV to far-infrared. The pluralities of information carrying wavelengths are combined into a multiple wavelength WDM optical signal that is transmitted in a single waveguide. In this manner, WDM systems can increase the transmission capacity of existing SDM/TDM systems by a factor equal to the number of wavelengths used in the WDM system.
Optical WDM systems were not initially deployed, in part, because of the high cost of electrical signal regeneration/amplification equipment required to compensate for signal attenuation for each optical wavelength throughout the system. The development of the erbium doped fiber optical amplifier (EDFA) provided a cost effective means to optically regenerate attenuated optical signal wavelengths in the 1550 nm range. In addition, the 1550 nm signal wavelength range coincides with a low loss transmission window in silica based optical fibers, which allowed EDFAs to be spaced further apart than conventional electrical regenerators.
The use of EDFAs essentially eliminated the need for, and the associated costs of, electrical signal regeneration/amplification equipment to compensate for signal attenuation in many systems. The dramatic reduction in the number of electrical regenerators in the systems, made the installation of WDM systems in the remaining electrical regenerators a cost effective means to increase optical network capacity.
EDFAs have proven to be a versatile, dependable, and cost effective optical amplifier in optical transmission system. EDFAs can amplify optical signals over a wavelength range spanning from approximately 1500 nm to 1600 nm. In addition, the amplification is polarization independent and introduces only low levels of channel to channel crosstalk.
However, the characteristics that make EDFAs so useful, also have some negative side effects. For example, because EDFAs provide gain over a wavelength range of the WDM signal, the amplification of the each channel varies with the power of the channel, as well as the total WDM signal power. Therefore, if a channel is added or dropped or a channel has a power variation, all of the channels will experience a gain variation that adversely affects the signal quality.
In addition, EDFAs do not equally amplify each channel within the wavelength range. Thus, when channels are added or dropped or a channel has a power variation, the remaining channels will not only incur gain variations, but the gain variations will generally be nonuniformly distributed across the remaining channels.
The signal degradation resulting from nonuniform gain variations across the wavelength range is compounded in systems having cascaded EDFAs as would be expected. The gain variations, especially in cascaded amplifier chains, can introduce system instability and noise that results in signal distortion, attenuation, and/or loss, and greatly diminish WDM system performance.
Automatic gain control ("AGC") and automatic power control ("APC") techniques have been developed to compensate for or suppress channel gain variations in EDFAs. AGC and APC schemes for controlling amplifiers are generally similar in operation owing to the amplifier relationship that PowerOUT/PowerIN=Gain.
AGC and APC schemes can generally be categorized as feedback or feed-forward amplifier control schemes depending upon whether the signal is monitored after passing through the amplifier or before entering the amplifier. A general description of AGC and APC schemes can be found in "Erbium-Doped Fiber Amplifiers, Principles and Applications" by Emmanuel Desurvire (1994), pp. 469-480 ("EDFA94"), which is incorporated herein by reference. A brief, more recent summary is provided in "Dynamic Effects in Optically Amplified Networks", Optical Amplifiers and their Applications ("OAA") Jul. 21-23, 1997, MC4-1-4, ("OAA97-1").
Amplifier control in either scheme is generally achieved by one of two methods. The first method is to control the amplifier gain or power by varying the amplifier pump power in response to the monitored signal, such as described in U.S. Pat. Nos. 4,963,832 and 5,117,196. The second method is to introduce a compensating, or control, signal to control the amplifier gain or power, such as described in U.S. Pat. No. 5,088,095 and "Dynamic Gain Compensation in Saturated Erbium-Doped Amplifiers", IEEE Photonics Technology Letters, v3, n5, pp. 453-455 (1991) ("PT91-1").
Feedback control can be based on monitoring one or more signal channels or pilot tones, and/or optical noise at the exit of the amplifier, as described in the above-referenced documents. Further examples of pilot tone monitoring can be found in Electronics Letters, Sep. 14, 1989, v25, n19, pp. 1278-1280, ("EL89-1") and total optical power monitoring can be found more recently in OAA Jul. 11-13, 1996, PDP4-1-5 ("OAA96-1"). In U.S. Pat. No. 5,506,724, ASE associated with a counter-propagating compensating/control channel is monitored to provide feedback control over the control channel.
All optical gain control methods are described in Electronics Letters, Mar. 28, 1991, v27, n7, pp. 560-1, ("EL91-1") and U.S. Pat. No. 5,239,607. The all optical AGC schemes couple amplified spontaneous emission ("ASE") from the amplifier through a feedback loop, which is injected into the amplifier input to form a ring laser. The formation of the ring laser locks the gain of the amplifier independent of the input power of the signal at other wavelengths.
Feedback schemes are generally desirable, because the schemes can also account for changes that occur in amplifier performance over time, as well as the input power changes. See "Automatic Gain Control in Cascaded Erbium Doped Fibre Amplifier Systems", Electronics Letters, Jan. 31, 1991, v27, n3, pp. 193-195, ("EL91-2").
Conversely, feed-forward schemes do not inherently account for variations in amplifier performance. However, feed-forward schemes in amplifier chains can indirectly account for variations in preceding amplifiers, because the variations will generally evidence themselves in input power variations in successive amplifiers.
An advantage of feed-forward schemes, as discussed in PT91-1, is that the schemes can be implemented without feedback from remote amplifier sites. Therefore, feed-forward control loops can be deployed at logistically convenient locations in a network and operated independently from the amplifiers, as discussed in EL91-2 . Also, feed-forward schemes allow the WDM signal to be monitored before or after control channels are combined with the optical signals.
As described in EDFA94 (pages 475-6), it is desirable to control input signal variations at optical switching nodes in optical networks to equalize signals originating from different stations. Either feedback or feed-forward control can be provided to control the signal input power. For example, see Optical Fiber Communication ("OFC") Conference Technical Digest 1997 TuP4, pp.84-5 ("OFC97-1"), 22nd European Conference on Optical Communications 1996 ("ECOC96") 5.49-52 and European Patent Application No. 0829981A2.
While the signal input can be equalized at each node in a network, it generally remains necessary to provide individual amplifier control along an amplifier chain to account for amplifier performance variations. In this regard, EDFA94 (page 472) cautions that "cancellation of transient saturation is achieved by keeping constant not the total EDFA input power, but the sum of all input powers weighted by their respective saturation powers". However, the author concedes that in WDM systems, the required spectral analysis to control amplifiers based on balancing the amplifier saturation is not practical.
Another shortcoming of current control channel schemes is that the schemes can not be used to protect against large power variations, which may occur in dense WDM systems. Large increases in the control channel power during gain transients can produce spectral hole burning in EDFAs that can degrade the system performance to a greater extent than the gain transients itself. As such, current control channel schemes have limited applicability in WDM systems.
In view of the expanding use of WDM systems and the desire to perform optical networking, it is becoming increasingly necessary to provide more precise and versatile amplifier control. The more highly controllable amplifiers and systems will help drive the further development of high capacity, more versatile, longer distance communication systems.
The apparatuses and methods of the present invention address the above need for higher performance optical systems. Optical systems of the present invention generally include an optical signal controller disposed along an optical link between two optical nodes. The optical signal controller is configured to provide a monitoring signal from an optical signal passing between the nodes in a plurality of wavelength sub-bands at least one of which includes a plurality of signal channels. The optical signal controller introduces power in a plurality of compensating channels the intensity of which is a function of the monitoring signal power in the plurality of wavelength sub-bands or the total power. The compensating channels are combined with the optical signal to compensate for power variations in the signal channels passing between the nodes.
In various embodiments, the optical signal controller can be configured to provide analog or digital control over performance variations that occur in one or more optical amplifiers in the link. Performance control is achieved by monitoring the input power to the amplifier in two or more sub-bands of the amplifier wavelength range. The optical signal controller then varies either the power of one or more compensating channels and/or the amplifier power in response to the monitoring signals to minimize the gain variations within each sub-band.
Compensating, or control, channels can be provided to compensate for input power/gain variations within each of the sub-bands. The compensating channels can be at wavelengths within or outside the wavelength range of the compensated sub-band. The compensating channel sources can be responsive to power variations in more than one sub-band. In various embodiments, the power in two or more compensating channels can be varied to maintain an average gain in the remaining signal channels or total optical signal power.
The compensating channels can be introduced at nodes, which include optical components, such as transmit and/or receive terminals, optical routers, switches, and add/drop devices, or at other monitoring points in the link including amplifier sites. Likewise, the compensating channels can be removed at various monitoring points and reinserted to provide flexibility in the control of each sub-band throughout the optical link.
In various embodiments, the compensating channels can be used to carry information signals between two points. For example, one or more of the compensating channels can be used to carry communication traffic (payload) between nodes and/or monitoring points on the link. In this manner, dedicated add/drop capacity can be provided within the link without sacrificing system signal channel capacity. Similarly, one or more of the compensating channels can be used to carry system supervisory information through the link directly between two points.
Optical systems of the present invention can include a plurality of nodes and links interconnected optically and/or electrically to form an optical network. The optical systems can also include network management to provide monitoring, provisioning and control of various network nodes and elements, such as amplifiers, etc., wavelength allocation and provisioning in the optical system.
The controller can generally be operated employing optical-electrical control loops and all-optical loops depending upon the system configuration. In various embodiments, an optical splitter is used to provide the monitoring signal in a wavelength range of interest from the optical signal passing through transmission fiber in the link. In embodiments, the monitoring signal can be provided before or after the insertion of the compensating channels at the input to an amplifier. Alternatively, the power in the sub-bands can be monitored and controlled based on the output of an amplifier.
The wavelength range can be partitioned into sub-bands based on the gain profile of the optical amplifier(s) being used in the system. Each sub-band monitoring signal can be used to control its corresponding compensating channel source to maintain a gain profile within the sub-bands as the optical signals pass through optical amplifiers. It is generally desirable to partition the wavelength range into sub-bands over which the gain profile of the optical amplifier(s) is substantially constant or does not greatly vary. In this manner, the variation in the compensating channel power will generally track the variation of the input signal power in that sub-band.
Compensating channels can be used in combination with pump control to compensate for input signal variations in the amplifiers. In some instances, it may be desirable to provide for control in the link using both compensating channels to minimize input power variations and pump control. Alternatively, the monitoring signals can be used to control the gain of the amplifier by varying the pump power, drive current, etc. provided to the amplifier.
In an embodiment, the optical signal controller is positioned before a first of one or more EDFAs. The wavelength range is divided into four contiguous sub-bands spanning the wavelength range of a WDM signal being amplified in the link. One compensating channel at a wavelength within each sub-band is used to compensate for gain variation within the sub-band. The compensating channels are controlled based on the power within the sub-band to substantially compensate for power variations introduced into the optical link. The compensating channels of the present invention can also be used in combination with various AGC and APC schemes at the individual amplifiers. The AGC or APC schemes can use either the signal channels or the compensating channels to control the amplifier performance.
Thus, the apparatuses and methods of the present invention provide for control of the gain profile over a range of wavelengths in optical transmission systems. Accordingly, the present invention addresses the aforementioned problems and provides apparatuses, methods, and optical systems that provide increased control over optical signal characteristics in the system. These advantages and others will become apparent from the following detailed description.
Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings for the purpose of illustrating embodiments only and not for purposes of limiting the same; wherein like members bear like reference numerals and:
FIGS. 1-4 show optical systems of the present invention;
FIGS. 5-8 show controller embodiments of the present invention; and,
FIGS. 9-10 show various optical source embodiments of the present invention.
FIG. 1 shows an embodiment of an optical system 10 including an optical controller 12 positioned to control one or more characteristics of an optical signal passing between two optical processing nodes 14 in an optical link 15. The system 10 can be embodied using one or more serially connected point to point links (FIG. 1) or in a network, which can be configured in various architectures (FIG. 2) and controlled by a network management system 16.
The optical signal controller 12 can be disposed at various monitoring points along a transmission fiber 18 in the optical link 15 between two nodes 14, as shown in FIG. 2. For example, the signal controller 12 can be selectively positioned relative to one or more optical amplifiers 20 disposed along the transmission fiber 18 to control the characteristics of the optical signal being amplified in the link 15.
It is often desirable to position the signal controller 12 at the same physical site as one or more of the nodes 14 at the beginning of the optical link 15. In this configuration, the optical signal characteristics can be controlled through the entire link from a logistically convenient location.
As shown in FIG. 3, the optical system 10 will generally include at least one transmitter 22 for transmitting optical signals including at least one information carrying signal wavelength λi, "signal wavelength or channel", through the optical transmission fiber 18. Furthermore, the optical system 10 will generally include at least one optical signal receiver 24 for receiving the optical signals from the fiber 18. Also, the controller 12 can be included near or within the node 14 as shown in FIG. 3.
The system 10 shown in FIG. 3 can be deployed as a WDM system including a plurality of transmitters 22 i for providing a plurality of information carrying wavelength λn to a plurality of receivers 24 j. Wavelength selective or non-selective optical combiners 26 can be used to combine the optical signals produced by the transmitters 22 i into a WDM optical signal that is transmitted through the transmission fiber 18. Optical distributors 28 are provided to distribute, either selectively or non-selectively, the WDM signal to the receivers 24 j.
The transmitters 22 used in the system 10 will generally include a laser optical source, but can include other coherent as well as suitable incoherent optical sources as appropriate. Information can be imparted to an optical carrier either by directly modulating a laser or by external modulating an optical carrier emitted by the laser. Alternatively, the information can be imparted to an electrical carrier that can be upconverted onto an optical wavelength to produce the optical signal. Similarly, the optical receiver 24 used in the present invention can include optical receivers known in the art employing various detection techniques, such coherent detection, optical filtering and direct detection, and combinations thereof. Additional versatility in systems 10 configured as networks, such as in FIG. 3, can be provided by employing tunable transmitters 22 and receivers 24 in optical nodes 14.
An embodiment of the optical signal controller 12, shown in FIG. 3, includes one or more optical compensation sources 30 for providing power in one or more compensating, or control, channel wavelengths λci, "compensating channels". The compensating channels are combined with the optical signal channels λi via the combiner 26 and transmitted through the fiber 18 in the link 15. The controller 12 also includes an optical distributor 28, such as a low ratio splitter/tap, to provide a monitoring signal within a wavelength range of interest from the optical signal passing through the transmission fiber 18.
The optical combiners 26 and distributors 28 can include wavelength selective and non-selective ("passive"), fiber and free space devices, as well as polarization sensitive devices. Standard or WDM couplers/splitters, circulators, dichroic devices, prisms, gratings, etc., which can be used alone or in combination with various tunable or fixed wavelength transmissive or reflective filters, such as Bragg gratings 34, Fabry-Perot devices, etc. in various configurations of the optical combiners 26 and distributors 28. Furthermore, the combiners 26 and distributors 28 can include one or more stages incorporating various devices to multiplex, demultiplex, or broadcast signal wavelengths λi in the optical systems 10.
Source controllers 32 are configured to receive the monitoring signal within respective sub-bands and control the optical compensation sources 30 in response to the monitoring signals. Alternatively, the source controllers 32 can be configured to control the plurality of compensation sources 30 in response to the total optical signal power or a combination of the sub-band and total powers.
The absolute and relative locations where the compensating channels λci are introduced into the fiber 18 and the monitoring signal is provided from the fiber 18 can be varied as appropriate. The monitoring signal can include both the compensating channels and the signal channels to provide feedback control over the compensating channel powers.
Likewise, the compensating channels λci can either be removed before or at the end of the link 15 depending upon the system configuration. It is generally desirable to separate and reinsert compensating channels λci respectively before and after combining signal channels from different links 15 to provide increased system control and flexibility.
The optical signal controller 12 can also beused to transmit communication traffic (payload) and/or system supervisory information via the compensating channels between nodes 14 or various monitoring points within the link 15. When used to transmit communications traffic, transmitters 22 can generally be used as the optical compensating sources 30. It will be appreciated that appropriate modification of the transmitter 22 to provide for variable power in the signal carrying compensating channels may be necessary.
FIG. 4 shows an embodiment of the optical system 10 including a plurality of optical signal controller 12 embodiments. The controllers 12 can be embodied as feed-forward or feedback control schemes. The source controller 32 can include an optical to electrical converter, such as a wavelength selective or non-selective optical receiver 24 to receive the monitoring signal. The optical to electrical converter can be a photodiode 34 that provides an electrical monitoring signal to the source controller 32, which is used to control one or more optical compensation sources 30 and/or optical amplifiers 20. As shown in FIG. 4, the amplifier 20 can include doped, i.e., erbium, or Raman fiber amplifiers 36 supplied with pump energy supplied by a pump source 38, as well as other optical amplifiers. The source controller 32 can be configured to control the pump source 38 in response to the monitoring signal.
The optical signal controller 12 can be configured to maintain a substantially constant optical signal power distribution in optical links 15. A constant optical power distribution in the links 15, facilitates substantially constant optical amplifier gain performance. Thus, the gain of the individual signal channel being transmitted through the link 15 can be controlled to a substantially constant value, if desired. In addition, the power of the individual signal channels can be controlled to maintain uniform and non-uniform gain profiles over the wavelength range as may be desired.
In various embodiments, the optical signal controller 12 employs a plurality of compensating channels to maintain a substantially constant gain profile for the optical signal in the link 15. The compensating channel wavelengths λci can be within or outside corresponding sub-band wavelength ranges of the optical signals being transmitted in the link 15. For example, the wavelength range of the signal channels in the link 15 could be divided into four adjacent sub-bands, each of which include a compensating channel at a wavelength within the sub-band. The compensating channels can be controlled in feed-forward or feedback schemes and can also be used in various AGC and APC schemes used to control the individual amplifiers.
The optical signal controller 12 is generally configured to compensate for power changes within the sub-bands of the optical signal before the amplifier gain profile is substantially impacted. For example, the optical signal controller 12 responds to a sudden reduction of the optical power within a sub-band by increasing the optical power supplied by the optical compensating source 30 associated with that sub-band. Likewise, if an increase in optical power is detected in the sub-band, the controller 12 must decrease the optical power output supplied by the compensating source 30 on a similar time scale.
The required response time of the controller 12 is a function of the number of cascaded amplifiers in the link 15. One of ordinary skill will appreciate that the required response time affects the choice of electronics to practice various embodiments of the invention.
FIGS. 5(a-c) show an exemplary layouts of a digital and analog sub-band control loops that can be used in the controller 12 to control the sub-band compensating channel power. Generally, the controller 12 includes a sub-band demultiplexer 28 d to separate the monitoring signal into sub-band optical signals. Optical to electrical converters, such as photodiodes 34, are used to detect the sub-band optical signal and generate electrical monitoring sub-band input signals Si. The sub-band source controller 32 uses the electrical monitoring input signals Si to vary the compensating channel power provided by the sub-band compensating source 30 in response to fluctuations in the sub-band input signal power. A low loss combiner 26, such as a circulator 40 and Bragg grating 42 arrangement, can be used to combine compensating channels with the WDM signal channel in the transmission fiber 18.
As further shown in FIG. 5(a), the sub-band source controller 32 will generally include an analog to digital ("A/D") converter 44 to provide the sub-band input signal Si as a digital signal to a sub-band input comparator differencing circuit 46. A setpoint power SPi, which can be programmable, is provided for each sub-band to the differencing circuit 46 and a monitor input error Ei is generated. The differencing circuit 46 can provide the absolute error calculated or apply an error threshold to the calculated error. The error threshold can be programmably set to minimize jitter or other noise in the signal from causing unnecessary, and possibly destabilizing, power variations in the control loop.
An error accumulator circuit 48 is used to provide a digital bias drive signal Bi in response to the monitor error signal Ei to a digital to analog ("D/A") converter 50 to control the compensating channel power supplied by the sub-band optical source 30. An exemplary error accumulator circuit 48 for a sub-band control loop is shown in FIG. 5(b) as an overall high-pass filter arrangement. It will be appreciated that other filter arrangements can be used in the error accumulator circuit 48. The arrangement shown in FIG. 5(b) is configured to drive detected signal channel input power variations to zero by varying the output power of the source 30 in response to the detected variations. The bandwidth of the high-pass filter response generally establishes the length of time during which the control laser output level is perturbed before the correction occurs.
In the error accumulator circuit 48, the setpoint power input error Ei is amplified using a first signal amplifier 52 1 and provided to a summing circuit 56, which accumulates the error. A feedback loop including a second amplifier 52 2 and an addressable memory 54 is used to implement the necessary bias signal value storage function of the error accumulator. The stored bias signal value is fed back to the summing circuit 56. The bias signal can be used to directly vary the output power of the sources 30 and thereby the compensating channel power. Alternatively, the output of the error accumulator circuit 48 can be used to control an external modulator or optical attenuator to vary the compensating channel power being introduced into the transmission fiber 18.
The response of the controller 12 shown in FIG. 5(b) can be modeled using a sampled-time analysis, where the z-transform of the control loop transfer function can be derived as:
Bout/Bin(z)=(z−G2)/(z−(G2−G1)) and the frequency response is Bout/Bin(ω)=(ejωT−G2)/(ejωT−(G2−G1)).
Bin and Bout=input and output bias signal, respectively,
G1 & G2=gain of amplifiers 52 1 and 52 2, respectively,
T=sample time,
z=ejωT (transform of the frequency)
In the embodiments shown FIG. 5(a), a monitoring signal is removed from the input transmission fiber 18 I after the compensating channelsignal has been inserted into the fiber 18. Thus, the monitoring signal includes both the signal channels and the compensating channels. As previously discussed, the monitoring signal can be removed before the compensating channels are introduced, so as to include only the signal channels, if so desired. Also, the monitoring signal can be passively or actively removed from the fiber in either a wavelength selective or non-selective manner. Typically, the monitoring signal will be removed by employing a low coupling ratio, non-wavelength selective tap coupler to split off a small percentage of the total signal.
The control loops can alternatively be implemented as an analog circuit, an example of which is shown in FIG. 5(c). The output from the sub-band photodetectors 34 s are provided to respective analog differencing amplifiers 53 i, either directly or via a fixed or variable attenuator 55 i, which can be used to provide additional control the sub-band loop. A wideband detector photodiode 34 w can be used to measure the total input power of the monitoring signal. The total input power can be compared to a total power set point in one of the differencing amplifiers 53 and a total input power correction provided to the sub-band differencing amplifiers 53.
Similarly, in various digital embodiments generally shown by FIG. 6, the wideband detector photodiode 34 w can also be incorporated to provide a wideband monitoring signal Sw for input power error correction. The electrical sub-band monitoring input signals Si are summed in another summing circuit 56 into a composite sub-band input signal Sc, which is compared to the wideband monitoring signal Sw in another comparator/differencing circuit 46. An input offset signal Ie is generated by the differencing circuit 46 and sent to each of the sub-band control loops. A multiplying circuit 58 allocates the input offset Ie based on sub-band error allocation setpoints Ki. The input offset Ie can be added to either the sub-band monitoring input signal Si or the setpoint power input error signal Ei depending upon the control loop configuration.
A mismatch between the composite sub-band signals Sc and the wideband detector signal Sw is indicative of variations in the frequency demultiplexer 28 d, the sub-band detectors 34 s, or the wideband detector 34 w. Error allocation in the controller 12 can be performed via numerous algorithms and statically or dynamically allocated in various distributions depending on the controller 12 configuration. For example, individual setpoints Ki and multiplying circuits 58 can be provided for each sub-band or a common multiplying circuit 58 can be used to equally distribute various errors in the controller 12.
The signal controller 12 can include one or more central processors 60 to monitor and control the sub-band control loops. The processors 60 can communicate with the network management system 16 to receive instructions and provide performance information, such as when non-zero input offset Ie or other performance variations that occur in the controller 12.
Analogous to the input offset monitoring, fault monitoring and remediation can be provided using an error distribution loop, as shown in FIG. 7, to redirect sub-band gain control to other viable loops in the event of a sub-band loop failure. In various embodiments, the set point input error Ei is compared with the set point power SPi to determine whether a sub-band control loop has failed. When a sub-band control loop failure is detected, a line switch 62 passes a failure error signal, typically the set point value SPi, to another summing circuit 56, which accumulates the failure error signals from the sub-bands. The control loop failure determination can be performed using the central processor 60 or a locally employed decision circuit in the line switch 62. The central processor 60 can also be used to make appropriate modifications to the correction set points for the remaining control loops depending upon the failure. In addition, the failure determination decision threshold can be programmably implemented to provide flexibility in the controller 12.
Alternatively, the decision circuit 62 can compare the input set point SPi directly with the sub-band input Si, as in FIG. 8. A common multiplying circuit 58 is also shown in the embodiment of FIG. 8, in which the error from a failed sub-band loop is evenly distributed among the surviving loops.
The various errors in the control loops can be distributed using any number of schemes. For example, the error can be distributed among the surviving sub-band loops to maintain the gain profile of the optical signal. Alternately, the cumulative failure error signals may be divided among the remaining loops according to the inverse proportion of the current laser bias of each loop. This method would lessen the probability that any one of the surviving sub-band loops would be overloaded upon the failure of an adjacent sub-band loop. The central processor 60 can be used to monitor the redistribution of the error and modify the redistribution to equalize or balance the power output from the sub-band loops depending upon the channel profile to be maintained.
The accuracy and speed of response of the controller 12 depends on a stable response from the optical compensating sources 30 to the bias drive level. The speed and accuracy of the response will generally vary over time; therefore, recalibration of the controller 12 will most likely be required to maintain performance levels.
As shown in FIG. 8, one or more of the central processors 60 in the controller 12 can be used to oversee the operation and perform calibration of the sub-band control loops. Each control loop can include a calibration device 64 for controlling the drive signal applied to the optical source 30. The calibration device 64 can be a digital device, such as a calibration table, or an analog device, such as a linear circuit.
During calibration, a switch 66 is used to by-pass the calibration device 64 and allow the central processor 60 to apply one or more test bias signal to the sub-band sources 30. As shown in FIG. 8, the position of the switch 66 will depend on whether an analog or digital calibration device 64 is implemented in the optical signal controller 12. The error distribution loop and fault control techniques previously described will adjust the compensating channel sources 30 that remain in operation to compensate for the variation in the compensating channel from the source 30 being calibrated.
The optical power of the source 30 can be calibrated by various known methods, for example by using a series of stepped bias levels. An optical spectrum analyzer ("OSA") or other wavelength selective receiver 68 can be used to measure the test output power of the selected source 30 independently of the photodiode 34 associated with a particular sub-band. Alternatively, the test output power can be detected using the sub-band photodiode 34 s in the sub-band loop being calibrated. When used in combination, the OSA 68 can be used to calibrate the sub-band photodiode 34 s, as well as the sub-band source 30 and other components in the sub-band control loop.
The detected test output power from either the OSA 68 or sub-band photodiode 34 is fed back to the central processor 60 for characterization of the source 30 being calibrated. The characterization can be used to develop a new calibration table for the source 30, which can be implemented when the source 30 is brought back on-line. In this manner, each source 30 in the controller 12 can be calibrated without removing the controller 12 from on-line operation. While it is possible to configure the controller 12 to perform simultaneous multiple calibrations, it is generally not desirable given the power distribution that may be necessary in the remaining operational sub-band control loops.
In embodiments exemplified in FIG. 8, the OSA 68 is positioned to calibrate the sources 30 based on the sub-band signal in the transmission fiber 18. It will be appreciated that the OSA 68 can be included within the controller 12 to more specifically calibrate the optical sources 30. In some embodiments, it may be possible to substitute the OSA 68 for the wideband photodiode 34 w used to determine the sub-band input power offset.
The optical sources 30 used in the present invention can be conventional diode lasers as known in the art. As previously discussed, communication traffic or system supervisory information can be sent using the compensating channel, if an appropriate transmitter 22 is used as the source 30.
The optical source 30 used in the controller 12 generally have to be capable of operation over a wide power range to maintain the optical signal gain profile upon the failure of one or more sub-band control loops. The bandwidth of the source 30 must therefore be sufficiently broad to prevent Stimulated Brillouin Scattering ("SBS") during high power operation and sufficiently narrow not to interfere with adjacent signal channels. Broad band optical sources or narrow band sources that have been broadened, via dithering, external cavity gratings, or other techniques, can be used as the optical sources 30.
For example, the optical source 30 can be embodied as semiconductor optical amplifier ("SOA"), or fiber laser, 70 operated in a lasing mode and stabilized to a desired wavelength as shown in FIGS. 9(a-d). The SOA 70 can provide compensating channels over a wide power range and Bragg gratings 42, or other reflective elements 78, can be used to control the lasing wavelength and bandwidth. For example, in FIG. 9(a), a high reflectivity Bragg grating 42 H and a lower reflectivity grating 42 L can be written into fiber pigtails on the SOA 70 to control the lasing wavelength. In FIG. 9(b), a Bragg grating is provided on an output port of a passive or wavelength selective coupler 72 in a ring configuration with the SOA 70. In various embodiments, the reflective element 78, i.e., Bragg grating 42, can be tuned to vary the output wavelength of the SOA source 30.
As shown in FIGS. 9(c-d), the optical source 30 can include the SOA 70, or a fiber laser, that is frequency stabilized using a feedback loop incorporating a saturable absorber 74, such as an unpumped erbium fiber. In embodiments exemplified by FIG. 9(c), an external cavity is formed using a three port circulator 40 in a feedback ring configuration and a wideband reflective device 78. Course mode selection in the feedback ring can be made using a narrow pass filter 76, such as a Fabry-Perot filter. The saturable absorber 74 serves to lock the lasing mode of the SOA 70 or fiber laser within the passband of the filter 76.
Similarly, the circulator 40 can be replaced by a wavelength selective or passive coupler 72 and the SOA 70, or fiber laser, can be incorporated into the ring as shown in FIG. 9(d). Furthermore, an isolator 80 can be employed to provide a unidirectional propagation in the ring embodiments.
Course wavelength selection in saturable absorber embodiments will generally provide one or more lasing modes within the desired wavelength range, one of which will tend to become the dominant mode. As the dominant mode or modes emerge, the saturable absorber 74 will act to prevent mode hopping because of the high loss associated with modes outside the saturating dominant modes. Also, an external frequency source can be used in place of the narrow band filter 76 to select the saturating mode/frequency emitted by the source 30. The embodiments of FIGS. 9(a-d) have been described with respect to providing compensating channels, but can also be deployed as fixed or tunable wavelength optical sources in optical transmitters, local oscillators, and other optical source applications.
In another embodiment, the compensating channel provided by the optical source 30 can be broadened using embodiments shown in FIGS. 10(a&b). For example, the compensating channel can be phase modulated to maintain the compensating channel power, while broadening the signal by creating sidebands (FIG. 10(a)). A phase modulator 82 can be driven at multiple frequencies to control SBS in fibers having different core sizes and susceptibilities to SBS. The wavelength of the source 30, such as provided by a DFB laser, can be controlled using frequency locking devices 84 and schemes as is known in the art. Likewise, narrow band reflective devices 78, such as narrow band Bragg gratings 42, can be employed to further control the wavelength of the laser.
Similarly, the optical source 30, such as a DFB laser, can be dithered or modulated directly to broaden the linewidth of the source 30, as shown in FIG. 10(b). The amplitude of the dithering or modulating of the laser drive current can be varied with power to further decrease the susceptibility to SBS. As in FIG. 10(a) embodiments, the wavelength of the optical source 30 can be controlled using various narrow band wavelength selective devices 78, such as Bragg gratings.
Those of ordinary skill in the art will appreciate that numerous modifications and variations that can be made to specific aspects of the present invention without departing from the scope of the present invention. It is intended that the foregoing specification and the following claims cover such modifications and variations.
|Cited Patent
|Filing date
|Publication date
|Aug 8, 1989
|Oct 16, 1990
|At&T Bell Laboratories
|Erbium-doped fiber amplifier coupling device
|Aug 23, 1989
|Nov 20, 1990
|The Boeing Company
|Radiation-hardened optical repeater
|Jan 31, 1991
|Feb 11, 1992
|At&T Bell Laboratories
|Gain stabilized fiber amplifier
|Apr 23, 1990
|May 26, 1992
|Stc Plc
|Optical amplifier gain control
|Aug 12, 1992
|Jun 29, 1993
|At&T Bell Laboratories
|Measurement of an optical amplifier parameter with polarization
|Jun 23, 1992
|Aug 24, 1993
|Bell Communications Research, Inc.
|Optical fiber amplifier with flattened gain
|Mar 5, 1992
|Dec 7, 1993
|Mitsubishi Denki Kabushiki Kaisha
|Optical fiber amplifier and its amplification method
|Aug 28, 1992
|Mar 29, 1994
|Nec Corporation
|Optical fiber amplifier circuit comprising a control circuit for controlling a plurality of excitation light sources
|Aug 24, 1993
|Oct 3, 1995
|Mitsubishi Denki Kabushiki Kaisha
|Optical-fiber light amplifier
|Sep 21, 1994
|Apr 9, 1996
|Mitsubishi Denki Kabushiki Kaisha
|Gain controllable optical amplifier and applications thereof
|Feb 22, 1995
|Oct 8, 1996
|Nec Corporation
|Monitor control signal receiving apparatus for optical fiber amplifier
|Aug 31, 1994
|Oct 29, 1996
|Fujitsu Limited
|Method and apparatus for preventing occurrence of surge light in optical amplifier/transmitter apparatus
|Jul 28, 1995
|Jun 9, 1998
|Fujitsu Limited
|Wavelength-division-multiplexing optical amplifier
|Jun 18, 1997
|Jan 5, 1999
|Corning Incorporated
|Variable period amplitude grating mask and method for use
|Aug 20, 1997
|Jan 19, 1999
|Ditech Corporation
|Optical amplifier having dynamically shaped gain
|Jul 26, 1996
|Jan 26, 1999
|British Telecommunications Public Limited Company
|WDM network with control wavelength
|Feb 13, 1997
|Feb 9, 1999
|Fujitsu Limited
|Multi-wavelength optical batch amplification apparatus
|Dec 4, 1996
|Feb 16, 1999
|Northern Telecom Limited
|Gain clamped amplifier
|Oct 10, 1996
|May 4, 1999
|Lucent Technologies Inc.
|Method of fast gain control in WDM optical networks
|Feb 14, 1997
|May 4, 1999
|Lucent Technologies Inc.
|Broadband flat gain optical amplifier
|Sep 13, 1996
|May 25, 1999
|Lucent Technologies, Inc.
|System and method for mitigating cross-saturation in optically amplified networks
|Dec 2, 1997
|May 25, 1999
|Fujitsu Limited
|Optical amplifier
|Dec 31, 1996
|Jun 22, 1999
|Mci Communications Corporation
|Method of and apparatus for detecting and reporting faults in an all-optical communications system
|Oct 21, 1996
|Jul 13, 1999
|Nec Corrporation
|Apparatus for measuring optical transmission line property and optical wavelength multiplexing transmission apparatus
|Mar 11, 1997
|Jul 20, 1999
|Nec Corporation
|Optical fiber amp repeater of amplifying an optical signal and superimposing an auxiliary signal
|Mar 18, 1997
|Aug 17, 1999
|Lucent Technologies Inc.
|Interactive optical fiber amplifier, system and method
|Jul 22, 1997
|Nov 16, 1999
|Hitachi, Ltd.
|Optical amplification apparatus
|Dec 14, 1998
|Mar 14, 2000
|Hitachi, Ltd.
|Optical amplifier, method of controlling the output light from the optical amplifier, optical transmission system and method of controlling an optical transmission path
|Aug 29, 1997
|Jun 26, 2001
|Robert Bosch Gmbh
|Device with optical fibre amplifier
|Apr 28, 1998
|Nov 13, 2001
|Lucent Technologies Inc.
|Method and apparatus for controlling optical signal power in response to faults in an optical fiber path
|Oct 26, 1994
|May 3, 1995
|AT&T Corp.
|A method of mitigating gain peaking using a chain of fiber amplifiers
|Feb 11, 1997
|Aug 27, 1997
|Lucent Technologies Inc.
|Method of fast gain control in WDM optical networks
|Sep 2, 1997
|Mar 18, 1998
|Lucent Technologies Inc.
|System and method for mitigating cross-saturation in optically amplified networks
|Oct 3, 1997
|Apr 29, 1998
|Northern Telecom Limited
|Stable power control for optical transmission systems
|May 27, 1998
|Dec 2, 1998
|Alcatel Alsthom Compagnie Generale d'Electricit�
|Optical transmission system with dynamic compensation of the transmitted power
|Jun 17, 1998
|Dec 30, 1998
|Lucent Technologies Inc.
|Apparatus and methods for improving linearity and noise performance of an optical source
|Mar 20, 1998
|Apr 21, 1999
|Fujitsu Limited
|Optical transmission device and optical communication system
|Title not available
|Title not available
|Title not available
|Title not available
|Delevaque, E., et al, Gain Control in Erbium-doped fibre amplifiers by lasing at 1480nm with photoinduced Bragg Gratings written on fibre ends, Jun. 10th, 1993, vol. 29, No. 12, pps 1112-1114, Electronics Letters.
|Desurvire, E. et al., Dynamic Gain Compensation in Saturated Erbium-Doped Fiber Amplifiers, May 1991, vol. 3, No. 5, pps. 453-455, IEEE Photonics Technology Letters.
|Desurvire, Emmanuel, Erbium-Doped Fiber Amplifiers Principles and Applications, 1994, pps 469-480, 717-718, A Wiley-Interscience Publication. Published by John Wiley & Sons, Inc.
|Edagawa, N., et al., First Field Demonstration of Optical Submarine Cable Systems using LD-Pumped Er-Doped Optical Fibre Amplifier, Sep. 14, 1989, vol. 25, No. 19, pps. 1278-1280.
|Ellis, A. D., et al., Automatic Gain Control in Cascaded Erbium Doped Fibre Amplifier Systems, Jan. 31, 1991, vol. 27, No. 3. pps. 193-195, Electronics Letters.
|Jackel, Janet Lehr, et al, All-optical stabilization of cascaded multichannel erbium-doped fiber amplifiers with changing numbers of channels, 1997, pps. 84-85, OFC '97 Technical Digest.
|Karasek, M.; van der Plaats, J. C., Protection of surviving channels in a cascade of pump-loss controlled gain-locked EDFAs, Jul.-Sep. 1998, vol., 12, No. 3, pps. 105-112, International Journal of Optoelectronics.
|Kashyap, R., et al, Wavelength flattened saturated erbium amplifier using multiple side tap Bragg Gratings, May 27th, 1993, vol. 29, No. 11, pps. 1025-1026, Electronics Letters.
|Kishi, Naoto and Yazaki, Tomonori, Frequency Control of a Single-Frequency Fiber Laser by Cooperatively Induced Spatial-Hole Burning, Feb. 1999, vol. 11, No. 2., IEEE Photonics Technology Letters.
|Luo, G., et al., Relaxation oscillations and spectral hole burning in laser automatic gain control of EDFAs, 1997, p. 130, OFC '97 Technical Digest.
|Massicott, J. F., et al, 1480nm pumped erbium doped fibre amplifier with all optical automatic gain control, Jun. 9th, 1994, vol. 30, No. 12, pps. 962-964, Electronics Letters.
|Na, K. W. et al., Rate equation model for gain-clamped erbium-doped fibre amplifiers, Apr. 15th, 1999, vol. 35, No. 8., Electronics Letters.
|Srivastava, A. K., et al., Fast Gain Control in an Erbium-Doped Fiber Amplifier, Jul. 1996, Optical Fiber Communication Postdeadline Papers 1996.
|Srivastava, A. K., et al., Fast-Link Control Protection of Surviving Channels in Multiwavelength Optical Networks, Dec. 1997, vol. 9, No. 12, IEEE Photonics Technology Letters.
|Sun, Y. and Srivastava, A. K., Dynamic Effects in Optically Amplified Networks, Jul. 1997, Optical Society of America Technical Digest-Optical Amplifiers and their Applications.
|Takushima, Yuichi, et al., Gain Spectrum Equalization of All-Optical Gain-Clamped Erbium-Doped Fiber Amplifier, Feb. 1999, vol. 11, No. 2., pps. 176-178, IEEE Photonics Technology Letters.
|Wagner, Richard E., et al, MONET: Multiwavelength Optical Networking, Jun. 1996, vol., 14, No. 6, pps. 1349-1355, Journal of Lightwave Technology.
|Zirngibl, M., Gain Control in Erbium-Doped Fibre Amplifiers by an All-Optical Feedback Loop, Mar. 28, 1991, vol. 27, No. 7., pps. 560-561, Electronics Letters.
|Zyskind, J. L., et al, Fast Link Control Protection for Surviving Channels in Multiwavelength Optical Networks, 1996, pps. 5.49-5.52, 22nd European Conference on Optical Communications, ECOC '96 Oslo.
|Zyskind, J. L., et al., Fast Power Transients in Optically Amplified Multiwavelength Optical Networks, Feb. 29, 1996, Optical Communication Postdeadline Paper 1996.
|Citing Patent
|Filing date
|Publication date
|Dec 6, 2001
|Jun 15, 2004
|Xtera Communications, Inc.
|Method and apparatus for optical element management
|Nov 2, 2001
|Aug 30, 2005
|Nortel Networks Limited
|Optical power transient monitor
|Aug 28, 2001
|Sep 13, 2005
|Dorsal Networks, Inc.
|Methods of signal substitution for maintenance of amplifier saturation
|Mar 10, 2003
|Jan 31, 2006
|Corvis Corporation
|Optical transmission systems including optical amplifiers and methods of use therein
|May 16, 2005
|Aug 1, 2006
|Corvis Corporation
|Optical transmission systems including optical amplifiers and methods of use therein
|Dec 2, 2004
|Oct 17, 2006
|Transmission system and method for equalization of channels in the system
|Apr 11, 2003
|Nov 13, 2007
|Method and a system for monitoring the transmission of optical signals
|Oct 4, 2005
|Sep 9, 2008
|Jds Uniphase Corporation
|Spectrally resolved fast monitor
|Jan 30, 2006
|Jan 19, 2010
|Alcatel-Lucent Usa Inc.
|Chromatic dispersion compensation using wavelength tunable transmitter
|Aug 5, 2008
|Aug 3, 2010
|Jds Uniphase Corporation
|Spectrally resolved fast monitor
|Dec 7, 2006
|Mar 8, 2011
|Broadwing, Llc
|Optical transmission systems and amplifier control apparatuses and methods
|Dec 3, 2007
|Mar 29, 2011
|Buabbud George
|Fiber optic communication system with automatic line shutdown/power reduction
|Jun 20, 2011
|Apr 22, 2014
|Futurewei Technologies, Inc.
|Method of efficiently and safely adding and deleting channels in an amplified wavelength division multiplexing system
|Dec 7, 2000
|Jun 14, 2001
|Satoshi Mikami
|Optical communication system and optical repeater used for same
|Aug 28, 2001
|Mar 13, 2003
|Zhengchen Yu
|Methods of signal substitution for maintenance of amplifier saturation
|Mar 17, 2003
|Oct 2, 2003
|Corvis Corporation
|Optical transmission system and amplifier control apparatuses and methods
|Sep 8, 2004
|Feb 10, 2005
|Stephens Thomas D.
|Optical transmission system and amplifier control apparatuses and methods
|Jul 30, 2002
|Apr 14, 2005
|Chang-Joon Chae
|Optical csma/cd technique
|Dec 2, 2004
|Jun 9, 2005
|Transmission system and method for equalization of channels in the system
|Oct 4, 2005
|Apr 6, 2006
|Jds Uniphase Corporation
|Spectrally resolved fast monitor
|Dec 7, 2006
|Apr 19, 2007
|Broadwing Corporation
|Optical transmission systems and amplifier control apparatuses and methods
|Jan 30, 2006
|Aug 2, 2007
|Lucent Technologies Inc.
|Chromatic dispersion compensation using wavelength tunable transmitter
|Aug 5, 2008
|Jan 1, 2009
|Jds Uniphase Corporation
|Spectrally Resolved Fast Monitor
|Dec 3, 2007
|Jun 4, 2009
|Ipg Photonics Corporation
|Fiber optic communication system with automatic line shutdown/power reduction
|Jun 20, 2011
|Dec 20, 2012
|Futurewei Technologies, Inc.
|Method of Efficiently and Safely Adding and Deleting Channels in an Amplified Wavelength Division Multiplexing System
|Dec 22, 2003
|Jul 21, 2005
|Siemens Ag
|Verfahren und Anordnung zum Einf�gen von F�llsignalen
|Dec 22, 2003
|Feb 23, 2006
|Siemens Ag
|Verfahren und Anordnung zum Einf�gen von F�llsignalen
|Dec 4, 2003
|Jun 8, 2005
|Transmission controller and method for equalization of channels in a wavelength-division-muliplexing system
|U.S. Classification
|398/5, 398/79, 398/43, 398/136
|International Classification
|Cooperative Classification
|European Classification
|Jul 30, 1999
Owner name: CORVIS CORPORATION, MARYLAND
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Effective date: 19990730
|Nov 13, 2006
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|May 22, 2007
Owner name: BROADWING CORPORATION, TEXAS
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|Jun 30, 2011
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|Oct 15, 2014
|Fee payment
Year of fee payment: 12


text:
Canada June Retail Sales Disappoint, but Bigger Picture Offers Some Positives
By Paul Vieira
No question, Canada's retail sales data in June were poor. But the bigger picture shows Canadian consumers seem to be getting their groove back.
Statistics Canada said Thursday retail sales in June declined 0.6%, and were down 1.2% in volume terms. It attributed part of the pullback to flooding in Alberta and a construction strike in Quebec, which forced consumers to pare back food, alcohol and clothing purchases.
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text:
If you don't tell your story, someone else will.
"Life is so much more beautiful and complex than a number on a scale"
Musings from A Curvy Romance Writer
You've been criticizing yourself for years, and it hasn't worked. Try approving of yourself and see what happens - Louise Hays
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text:
Signs, Tesla
#----------------------------------PLEASE NOTE---------------------------------# #This file is the author's own work and represents their interpretation of the # #song. You may only use this file for private study, scholarship, or research. # #------------------------------------------------------------------------------## Received: from animal-farm.nevada.edu by redrock.nevada.edu (5.65c/M1.4) with SMTP id <AA14603> Fri, 12 Mar 1993 13:43:41 -0800 Received: from post1.INRE.ASU.EDU by animal-farm.nevada.edu id <firstname.lastname@example.com> Fri, 12 Mar 1993 13:43:37 -0800 Received: from ASUVM.INRE.ASU.EDU (MAILER@ASUACAD) by asu.edu (PMDF #2382 ) id <firstname.lastname@example.com> Fri, 12 Mar 1993 14:30:44 MST Received: from ASUACAD (IFSXM) by ASUVM.INRE.ASU.EDU (Mailer R2.10 ptf000) with BSMTP id 2848; Fri, 12 Mar 93 14:30:15 MST Date: 12 Mar 1993 14:29:17 -0700 (MST) From: Paul Zimmerman <email@example.com> Subject: CRD: Signs - Tesla To: email@example.com Message-Id: <email@example.com> Content-Transfer-Encoding: 7BIT TESLA Signs C Bm A G And the sign says long haired freaky people need not apply D Bm G A So I tuck my hair under my hat and I went in to ask him why Bm G He said you look like a fine outstanding young man, I think you'll do D A G A So I took off my cap and said imagine that, me working for you CHORUS D C G Signs, signs, everywhere signs D C G Fuckin' up the scenery, messin' my mind A G Do this, don't do that C Can't you read the sign? And the sign says all trespassers will be shot on sight So I jumped the fence and yelled at the house hey, what gives you the right You put up a fence to keep me out or to keep mother nature in If God were here he'd tell it to your face, man you're some kind of sinner CHORUS And the sign says you got to have a membership card to get inside solo over chord progression And the sign says everybody welcome come in kneel down and pray And at the end of it all they passed the plate around and I didn't have a penny to pay So I got me a pen and paper, and I made out my own fuckin' sign It said thank you, Lord, for thinkin' 'bout me, I'm alive and doin' fine CHORUS Peace, love, and soul, Paul Zimmerman
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text:
BA (Vind), MA (Dal)
Kristian grew up in small town Nova Scotia and came to King's for the first time to attend the Foundation Year Programme. After an enriching first year he went on to complete his BAH in Contemporary Studies and Political Science at King's/Dal. Following his undergrad Kristian studied French at Université Sainte-Anne in the beautiful Baie Sainte-Marie, and spent another year teaching English in France. He returned to King's for the first time to work as a Don and pursue an MA in Political Science at Dalhousie. Following the completion of his MA, Kristian left to purse other opportunities, but his work in residence at King's bought him back once again. In 2015 Kristian returned to King's yet again, bringing with him his experience in residence life at Dalhousie, Sainte-Anne, and King's, in a new position as Assistant Dean.
Outside of his work in residence Kristian is invariably found in the backcountry of Nova Scotia. He enjoys camping, hiking, paddling, and loves fly fishing and fly tying. When confined to the city he likes to spend time cooking, feasting with friends, and enjoying an occasional craft beer.


text:
TreeView.BeforeExpand Event
Occurs before the tree node is expanded.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
For more information about how to handle events, see Handling and Raising Events.
The following code example demonstrates how to change the collapse state of a TreeView so that all the checked nodes are visible. First, all the nodes are collapsed, and a handler is added for the BeforeExpand event. Next, all the nodes are expanded. The BeforeExpand event handler determines whether a given node has child nodes that are checked. If a node does not have checked children, the expansion is canceled for that node. In order to allow standard node expansion when the plus sign next to a node is clicked, the BeforeExpand event handler is then removed.
This behavior can also be implemented by handling the BeforeCollapse event, as illustrated in the example for that topic.
For the complete example, see the CheckBoxes reference topic.
private void showCheckedNodesButton_Click(object sender, EventArgs e) { // Disable redrawing of treeView1 to prevent flickering // while changes are made. treeView1.BeginUpdate(); // Collapse all nodes of treeView1. treeView1.CollapseAll(); // Add the checkForCheckedChildren event handler to the BeforeExpand event. treeView1.BeforeExpand += checkForCheckedChildren; // Expand all nodes of treeView1. Nodes without checked children are // prevented from expanding by the checkForCheckedChildren event handler. treeView1.ExpandAll(); // Remove the checkForCheckedChildren event handler from the BeforeExpand // event so manual node expansion will work correctly. treeView1.BeforeExpand -= checkForCheckedChildren; // Enable redrawing of treeView1. treeView1.EndUpdate(); } // Prevent expansion of a node that does not have any checked child nodes. private void CheckForCheckedChildrenHandler(object sender, TreeViewCancelEventArgs e) { if (!HasCheckedChildNodes(e.Node)) e.Cancel = true; } // Returns a value indicating whether the specified // TreeNode has checked child nodes. private bool HasCheckedChildNodes(TreeNode node) { if (node.Nodes.Count == 0) return false; foreach (TreeNode childNode in node.Nodes) { if (childNode.Checked) return true; // Recursively check the children of the current child node. if (HasCheckedChildNodes(childNode)) return true; } return false; }
Available since 1.1


text:
Down Jacket Merchant
299.95€ 149.95€ VAT included
- Lining thickness: very warm lining
- light material
- removable hood with drawstring
Color : Yellow
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Sporty maritime down jacket for the winter. Warmly lined and lightweight despite its down filling, this jacket is the perfect companion for cold days, whether in the city or by the sea.