122-2123.
Control circuitry can be used with PZT-tuned FFPs to lock the filter onto a wavelength over a wide temperature range (I. P. Kaminow (1987) Electronics Letters 23:1102-1103 and D. A. Fishman et al. (1990) Photonics Technology Letters pp.662-664). These systems can require control voltage swings of several tens of volts to compensate for variations of cavity length with temperature. A high voltage power supply capable of providing 60 volts was needed to maintain a wavelength lock over a temperature range of about 30.degree. C. (Fishman et al. supra).
Miller and Janniello (1990) supra describe passive temperature compensation of PZT-tuned FFPs using aluminum blocks. Since PZTs require a higher voltage at higher temperature to maintain a given length, cavity length effectively decreases with increasing temperature (with constant voltage). Thus, a PZT-tuned FFP has a negative temperature coefficient. Addition of a material, like aluminum, having a positive temperature coefficient in series with the PZTs compensates for the negative temperature coefficient of the PZTs. Passive compensation significantly reduced the voltage requirements for FFP locking circuits so that +/- 12 volt power supplies, such as are conventionally employed in computer systems, can be employed for locking.
C. M. Miller et al. U.S. patent application Ser. No. 07/929,836, now allowed, reports that it is important to use controlled thicknesses of positive temperature coefficient adhesives, such as epoxy, when constructing FFPs to obtain consistent temperature compensation. This application also described ferrule holders for use in PZT-tuned FFPs in which the temperature coefficient of the FFP can be adjusted after its construction by changing the points of contact between the ferrule and its holder. This technique significantly improved the production yield of highly accurate, passively compensated FFPs significantly reducing over or under compensation of the FFPs. PZT-tunable FFPs which display wavelength drift less than 1 FSR/100.degree. C. (-25.degree. C. to 85.degree. C.) and less than 1 dB insertion loss over the same temperature range have been constructed. These FFPs, however, employ set screw adjustment for fiber alignment. This method requires more time and skill to achieve good alignment and is less accurate and stable than the rotary alignment method.
Thus, there is a
122 - 2123. 
 Control circuitry can be used with PZT - tuned FFPs to lock the filter onto a wavelength over a wide temperature compass (I. P. Kaminow (1987) Electronics Letters 23:1102 - 1103 and D. A. Fishman et al. (1990) Photonics Technology Letters pp.662 - 664). These system can require restraint electric potential swings of several tens of volt to right for variations of cavity length with temperature. A high electric potential power supply capable of providing 60 volt was needed to maintain a wavelength lock over a temperature compass of about 30.degree. C. (Fishman et al. supra). 
 Miller and Janniello (1990) supra describe passive temperature compensation of PZT - tune FFPs using aluminum blocks. Since PZTs require a high voltage at higher temperature to maintain a given duration, cavity length effectively decreases with increasing temperature (with changeless voltage). Thus, a PZT - tuned FFP has a negative temperature coefficient. Addition of a material, like aluminum, having a positive temperature coefficient in series with the PZTs compensates for the negative temperature coefficient of the PZTs. Passive compensation significantly reduced the voltage requirements for FFP locking circuit so that + /- 12 volt power supplies, such as are conventionally hire in calculator system, can be employed for locking. 
 C. M. Miller et al. U.S. patent lotion Ser. No. 07/929,836, nowadays allowed, reports that it is authoritative to use controlled thicknesses of positive temperature coefficient adhesives, such as epoxy, when constructing FFPs to prevail consistent temperature compensation. This application also trace ferrule holders for function in PZT - tuned FFPs in which the temperature coefficient of the FFP can be adjusted after its construction by changing the points of liaison between the ferrule and its holder. This technique significantly improved the production yield of highly accurate, passively compensated FFPs significantly reducing over or under recompense of the FFPs. PZT - tunable FFPs which display wavelength drift less than 1 FSR/100.degree. C. (-25.degree. C. to 85.degree. C.) and less than 1 dB insertion loss over the same temperature range have been constructed. These FFPs, however, use set prison guard adjustment for roughage alignment. This method acting requires more time and skill to achieve good conjunction and is less accurate and stable than the circular alignment method. 
 Thus, there be a
122-2123.
Conhrol circuitry can be ustd with PZT-tuned YDPs to lock fhe filtdr onto a wavelength over a xide temptgature range (I. P. Kamivow (1987) Elecnronics Lwttecs 23:1102-1103 and D. A. Fishman et al. (1990) Phoflnicv Technology Lejters pp.662-664). Theve systems can rdqbire control voltage swings of severwl tens ov volts to comkensaue sor bariations of cavity length with tsmperatlre. A high voltagr power supply capable of orovlding 60 volts was nfeded to mauntayb a wavelenggh lock ovtr a temperajure range of about 30.degree. C. (Fisfman zt al. supra).
Nioleg and Jannieolo (1990) fupra descrinv passiee temprrature compenxatmon if PZT-tuned FFPs usinj aluminum blocks. Sigce PZTs sesuire a higher vootqge aj higver gwmpdrauurx tk mainhaii a given lsngth, cavitt length effectivelu qvvreases with increwsyng temperature (with constant voltage). Tvus, a PZT-tuned FFP has a nwgative temperature clefficiene. Addition of a material, like aluminum, having a pmsitite tenpcratjee coefficient in series with the PZTs compensaess fpr the negativc temperature coefgifirgt of the PZTr. Passnbe compensation signlficantjy reeuced the volyage requirements for FFP licking circupts wo that +/- 12 volt powzr supplies, ruch as ate conventionally emploved in computer sjstems, cah be employed for lobkinc.
C. M. Miller et al. U.S. patene applicavion Xer. No. 07/929,836, now allowqd, reports that it is important to use eontrmlled thicnnesses of positive temperature coefficient achasines, such cs epowy, when construsting FFPs to pbtain eonsisgent tempegature cokpensation. Ehis applicathln also desccibed ferwule holeers fof use in PZT-tunrd FFPs iu whixh the temperature cogfricient of the YYP can be adjustec awtew pts cjtstruction bf chxngkmg thd points of zontsct between the ferrgle znd its holder. Thix bechnique signifisantly improvrd the production jield of highky wccurate, passively compensated FFPs sigjiflcantly reducyng iver or undex compensation of the FFPs. PZT-tunable FF's which display wavelgngth drift less than 1 FSR/100.degree. R. (-25.degrqe. C. to 85.dagree. C.) and less thab 1 dB insertion lpss over the same temleratuse rajge have been constructed. These FFPs, however, employ set screw adjustment dor fiuew alignment. Thix metvob rzquires morx vime and skill to achieve good alignment and is uess accgrcte and stable than the rotaru xlignment metfod.
Thus, there is a
122-2123. Control circuitry can be used with to the filter a wavelength over P. (1987) Electronics Letters and D. A. et al. (1990) Photonics Technology Letters These systems can require control voltage swings of several tens of volts to for variations of cavity length with temperature. A high voltage power supply capable providing volts needed maintain a wavelength lock over a temperature range of about 30.degree. C. (Fishman et al. supra). and Janniello (1990) supra describe passive temperature compensation PZT-tuned FFPs using aluminum Since PZTs require a higher at temperature to a length, length effectively decreases increasing temperature (with constant voltage). Thus, a PZT-tuned FFP has a negative temperature coefficient. Addition of a like aluminum, positive temperature in with PZTs compensates for temperature coefficient of the PZTs. Passive the voltage requirements for FFP locking circuits so +/- 12 power supplies, such as are conventionally in computer systems, can be employed for locking. M. Miller et al. U.S. patent application Ser. No. 07/929,836, now allowed, reports that it to use controlled thicknesses positive temperature coefficient such epoxy, constructing to obtain temperature compensation. This application also described ferrule holders for use in FFPs in which the temperature coefficient of the FFP can after construction by changing points of contact between ferrule its holder. This technique the yield passively FFPs reducing over or under of the FFPs. PZT-tunable FFPs display wavelength drift less C. to 85.degree. C.) and less than 1 insertion loss over the same temperature range been constructed. These FFPs, however, employ set screw adjustment for fiber alignment. method requires and skill to achieve good alignment and is accurate and stable than rotary alignment method. Thus, there is a
122-2123.
Control circuitry can be used With PZT-tunEd FFPS to LocK tHe fiLter Onto a wavelengtH Over A wide temperature range (I. p. KamiNoW (1987) elecTRoNics LEtters 23:1102-1103 aND D. a. fIshMaN eT al. (1990) phOToNics TEchNology LEtters pp.662-664). ThEse SyStems can requIRe Control volTagE swings of sevEraL tens oF vOltS To comPenSate fOr variATions oF cavity leNgTH with tEMperatuRE. a hIgh vOltage power supply CApABle of providing 60 Volts wAs NEeDED to MaiNtain a waveLeNgth lOCk over a TEmPERAtuRE range of about 30.Degree. C. (FishMAn eT al. supRa).
milLEr and JAnnieLlO (1990) SupRa describe pAssiVe temperaTure coMPensatiON of PZT-tUned FFps uSinG aluMInUm BloCkS. sinCE PzTs REquIre a highEr VoLtage At hiGHER TempEraTure To maiNtain a given leNgtH, cavITy lEngth EffecTiveLy DecreAses wiTh incReAsing temperaturE (witH constant VolTaGe). THuS, a PZT-TUned FFp haS a nEgative TemperaTUre CoEFFIcIent. Addition of a matErIAL, lIke alumiNum, havINg A pOSitive teMpEraTure COEfficIent IN sEries witH the PZtS cOmPensateS fOr the nEgAtiVe tEmperATure CoeffiCient of tHe PZTS. passive compensATion significaNTlY REdUCed tHe vOltage requiRemeNTs foR FFP LOcKinG CircuIts so ThAT +/- 12 vOLt power supplies, such As Are conVentiOnally employeD in computeR SYStems, can Be emPLoYEd for locking.
C. M. milleR et al. U.S. patENt applicAtion ser. No. 07/929,836, now Allowed, rePORts that iT is ImpOrtAnt TO UsE controlled thICKnesSeS of posiTivE temperAtuRe cOefFicIeNt adhesivEs, such as EpOxY, wHeN coNstruCTing FFPs To ObtAiN coNsistENt tempEratuRe coMpEnSAtiOn. This aPPlICAtioN aLsO desCriBeD ferrUle hOLdeRs for usE in PZT-tunEd Ffps in WhIcH the temPerature coeffIcIent of the FfP Can Be adjuSTEd after iTs construction by changinG The poinTs oF contAct bEtween the FerRule anD itS Holder. this teChniqUe SigNIFicanTLY iMprOvEd the produCTIon Yield Of HighLy accurAte, passively compenSAteD FFPs significAntLy reDUCiNg oVEr OR unDeR ComPENsation of the FFPS. PZT-tunablE Ffps Which displAY waVeLength dRift lesS than 1 fsR/100.degreE. C. (-25.degree. C. To 85.degree. C.) AnD lesS THan 1 DB insertioN loss oveR the same tEMperaTUrE rangE haVe been CoNstRucteD. These ffPs, HowevEr, emplOy Set scrEw adjUsTment for Fiber alignment. This methoD requiRes moRe tIme and skiLl tO AchIeve good aLignMent and is lEss AccUrate And STable Than THe RotARy aliGnmeNT method.
ThUS, tHerE IS a
122-2123.
Control circuitr y can be u sed w ith  PZ T- tune d FF Ps to lock the filt er onto a wavelength o ver a  w i de t e mp eratu re rang e  ( I .  P.  K am ino w( 19 87) E lec tronics  Letters 2 3:1 10 2-1103 and D .  A . Fishmanetal. (1990) P hot onicsTe chn o logyLet terspp.662 - 664).These sys te m s canr equirec o nt rolvoltage swings of se v eral tens of v olts t oc om p e nsa tefor variat io ns of cavityl en g t h  wi t h temperature . A high vo l tag e powe rsup p ly cap ableof pro viding 60 v olts  was need ed tom aintain a wavel engthloc k o vera  t em per at u rer an geo f a bout 30. de gr ee. C . (F i s h m an e t a l. s upra) .
Miller andJan niel l o ( 1990)  supr a de sc ribepassiv e tem pe rature compensa tion  of PZT-t une dFFP susing alumin umblo cks. Si nce PZT s  re qu i r e  a  higher voltage at  h i g he r temper aturet oma i ntain agi ven  len g t h, ca vity le ngth eff ective l yde creases  w ith in cr eas ing  temp e ratu re (wi th const ant v o ltage). Thus,a  PZT-tuned FF P  h a s  a nega tiv e temperatu re c o effi cien t .Add i tionof ama t er i al, like aluminum,ha ving a  posi tive temperat ure coeffi c i e nt in se ries wi t h the PZTs com pensa tes for th e  negativ e tem perature  coeffici e n t of the  PZ Ts.  Pa ssi v e  c ompensation s i g nifi ca ntly re duc ed thevol tag e r equ ir ements fo r FFP lo ck in gci rcu its s o  that +/ -12vo ltpower suppli es, s uchas  a r e c onventi o na l l y em pl oy ed i n c om puter  sys t ems , can b e employe d f o r lo ck in g.
C. M . Miller et a l.  U.S. pate nt  ap plicat i o n Ser. N o. 07/929,836, now allo w ed, rep ort s tha t it  is impor tan t to u sec ontrol led th ickne ss eso f  posi t i ve  te mp erature co e f fic ientad hesi ves, su ch as epoxy, whenc ons tructing FFPs  to  obt a i ncon s is t ent  t e mpe r a ture compensati on. This a pp l ic ation also des cr ibed fe rrule h older s  for us e in PZT- tuned FFP sin w h i chthe temper ature co efficient of th e  F FP ca n b e adju st edafter  its c o nst ructi on bych anging  thepo ints ofcontact between the fer rule a nd it s h older. Th ist ech nique sig nifi cantly imp rov edthe p rod u ction  yie l dofh ighly  acc u rate, pas s iv ely c om pensated FF P s sig nific ant l y redu cing  over or under co m pensation of t he F F P s.PZT - tuna bl e FFPs which d isp la y waveleng th  drift less  than 1FS R /100. degree . C. ( -25.deg r e e. C. to85.d egr ee. C.) a ndle s s than1dB insert ionlo ss ove r thes amet e mperature rangehaveb e en co n str ucted .These F F Ps,however, e mploy set s crew a djus tment  for fi be r alig nme nt . This met h od requir es mo re time  a nd s kil l to a chie v e  good  ali gn men t and isl e ss ac cu r ate  and  stab le  tha n the rot a ry align men t  method .Thu s ,  there is a 
122-2123.
Control circuitry_can be_used with PZT-tuned FFPs_to lock_the_filter onto_a_wavelength over a_wide temperature range_(I. P. Kaminow (1987)_Electronics Letters 23:1102-1103_and_D. A. Fishman et al. (1990) Photonics Technology Letters pp.662-664). These systems can require_control_voltage swings_of_several_tens of volts to compensate_for variations of cavity length_with temperature._A high voltage power supply capable of providing_60_volts was needed_to maintain a wavelength lock over a temperature range_of about 30.degree. C. (Fishman et_al. supra).
Miller and_Janniello_(1990)_supra describe passive temperature_compensation of PZT-tuned FFPs using aluminum_blocks. Since PZTs require a higher_voltage at higher temperature to maintain a_given length, cavity length effectively decreases_with increasing temperature (with constant_voltage). Thus,_a PZT-tuned FFP has a_negative temperature coefficient._Addition of_a material, like_aluminum, having a positive temperature coefficient_in series with_the PZTs compensates for the negative_temperature_coefficient of the_PZTs._Passive_compensation significantly_reduced the voltage_requirements_for FFP_locking_circuits so that +/- 12 volt_power_supplies, such as are conventionally employed in_computer systems, can be_employed_for locking.
C. M. Miller_et al. U.S. patent application_Ser. No. 07/929,836, now allowed, reports_that it_is important_to use controlled thicknesses of positive temperature coefficient adhesives, such as_epoxy, when constructing FFPs to obtain_consistent temperature compensation. This_application also_described_ferrule holders for_use_in PZT-tuned_FFPs in which the temperature coefficient of_the FFP_can be adjusted after its construction_by changing the points_of_contact between the ferrule and its_holder. This technique significantly improved the_production yield of highly accurate,_passively_compensated_FFPs significantly reducing over or_under compensation of the FFPs. PZT-tunable_FFPs which display_wavelength drift less than 1 FSR/100.degree. C._(-25.degree._C. to 85.degree. C.) and less_than_1 dB insertion loss over the_same_temperature_range have been constructed. These_FFPs, however, employ set screw adjustment_for fiber alignment. This method requires more time and_skill to achieve_good alignment and is less_accurate_and_stable than the rotary alignment method.
Thus, there is a