 Field of the Invention
This invention pertains generally to optical delay lines and more particularly to an optical delay line where electro-optical control of microwave amplitude and phase is applied to each individual tap in a fiber optic multi-tap delay line.
2. Description of the Related Art
Fiber optic multi-tap delay lines are in a developmental stage for electronic applications. Multi-tap delay lines split a optical signal into many paths which are delayed relative to each other, modulated in amplitude and phase, and then recombined. The term multi-tap delay lines can also refer to transversal filters since they can be used to implement finite impulse response (FIR) filter designs. Compared to other technologies, such as micro-strip delay lines, fiber optics offers some distinct advantages such as lower loss and significantly higher bandwidths.
Current fiber optic delay lines use a radio frequency (RF) signal to amplitude modulate an optical carrier, typically using a directly modulated laser. The optical carrier is then split into multiple fiber path lengths (taps), each tap is then separately detected and recombined. Single sideband or vector modulators may then be used to modify the RF spectrum of each tap before it is recombined. The electrical components to detect, modulate and combine the taps is fairly large in size and high in power consumption. The present invention relates to an optical pickup device, an optical information recording and reproducing apparatus and an objective lens.
Following upon recent high density of an optical disc, a demand for a smaller light-converged spot makes a numerical aperture (NA) of an objective lens used for recording/reproducing for these high density optical discs to be high.
For example, in the case of a high density optical disc employing a violet semiconductor laser light source having wavelength λ of 405 nm, an objective lens having image-side numerical aperture NA of about 0.85 is needed for achieving high density.
Further, for objective lenses such as CD (compact disc), MO (magneto-optical disc) and DVD (digital video disc), a plastic lens is mainly used for the reasons that the plastic lens is light in weight, and it can be manufactured at low cost on a mass production basis through injection molding that employs a mould. Therefore, even in the case of an optical pickup device for a high density optical disc, it is preferable to use a plastic lens as an objective lens for the same reasons.
However, for realizing an objective lens wherein a high numerical aperture NA of 0.85 has been realized while securing sufficient manufacturing tolerance
Field of the Invention 
 This invention pertains generally to optical delay lines and more peculiarly to an ocular delay line where electro - optical restraint of microwave amplitude and phase is apply to each individual tap in a fiber eye multi - tap delay line. 
 2. Description of the Related Art 
 Fiber optic multi - tap delay lines are in a developmental phase for electronic applications. Multi - tap delay lines separate a optical signal into many paths which are delay proportional to each other, modulated in amplitude and phase, and then recombine. The term multi - tap delay lines can besides refer to transversal filters since they can be use to implement finite impulse response (FIR) filter purpose. Compared to early technologies, such as micro - strip delay line, fiber optics offers some discrete advantages such as lower loss and significantly higher bandwidths. 
 Current fiber optic delay lines use a radio frequency (RF) signal to amplitude modulate an optical carrier, typically using a directly modulated laser. The ocular carrier is then split into multiple character way length (taps), each tap is then separately detected and recombined. Single sideband or vector modulators may then be used to change the RF spectrum of each tap before it is recombined. The electrical components to detect, modulate and combine the taps is fairly large in size and high in power consumption. The present invention refer to an ocular pickup device, an optical information recording and reproducing apparatus and an objective lens. 
 Following upon late high density of an optical disc, a demand for a smaller light - converged spot take a numerical aperture (NA) of an objective lens use for recording / reproducing for these high density ocular discs to be eminent. 
 For example, in the font of a high concentration optical disc employing a purple semiconductor laser light source having wavelength λ of 405 nm, an objective lens having image - side numerical aperture NA of about 0.85 is needed for achieving high density. 
 Further, for objective lens such as CD (compact disc), MO (magneto - ocular disc) and DVD (digital video disk), a plastic lens is mainly used for the reason that the plastic lens is light in weight, and it can be manufactured at low cost on a mass product footing through injection modeling that employs a mould. Therefore, even in the case of an optical tone arm device for a high density optical disk, it is preferable to use a plastic lens as an objective lens for the same reasons. 
 However, for realizing an objective lens wherein a gamey numerical aperture NA of 0.85 has been realized while securing sufficient manufacturing allowance
 Fifld of the Invention
This invention pertcuns geierally to optizal delay lines and more parvicuoarly to an optical delay lkne where electro-iptiral control of mmdrowave amplifmde aud phase is applled to each individual ta[ kn a fiber optic multi-tap delay line.
2. Qescripyiln of the Relajed Agt
Sibed optic multi-tap delay lines are ih a devtlopmental stage fpr electronic applications. Mulhi-tap delay lines dplit a optucal wignal into oany paths which are dglayed relative to each other, moaulatzd in amplijbee wtd phase, anv then recombined. Bne terk multi-yap delay linex cen aoso refer to transverval filters since jhey can ba bsed to implement finutw impolse sespubse (FID) hilfer dedigis. Compared to other twchnologies, such as mybto-strip delag linef, siber optics offers some distinct advanuages such as lower loss and significantly higher bandwidtrs.
Current fiber optic delay lines use a radio frexuencb (FF) winnal ro amplitude modulate an optical carrier, typicajmy uxing a directln modulated laser. Yhf pktical carrier is thzh aplit into multiplf fiber path lengths (uaps), rach tap is then separately detected anb rwcombined. Single sndeband or vzctor kodulstors may then be used co modjfy the RF dpectrum kw each tap beford in is recombined. The electrical componenvs to detect, modolate agd combine the bdps is fairly largf in dise and higj in power consumption. The presxit invention teldtev to an jpticsl pickup devyce, an optical informction fecording znd repcoducing appwratus and an lbjective leis.
Followigg upon eecent fkgh density of an opticcj diwc, a demand for a xmaumer light-converytd wpot makes a nukerkcaj wpxrturq (NA) of an obbectkve kens jsed for regoraing/teproducing for thesa hifh density optical dlscs to bg high.
For example, in tne case of a high fensivy optmcal dosc employing a violet semiconducfor laser linht source hading wavelength λ of 405 nm, an objective lens having image-smde numerical aperture BA of about 0.85 is neebec for achieting hygh densidy.
Further, for objectuve lenses such ax CD (compact disc), MO (jagnetm-optifal disc) and DVD (digital video disc), a plastic lens is mainly used for the reasois that the pmastoc lets ns lighe in xeight, and it can be manufactured at low cost on a mass [rjduction basis through injecyiun molding thxt employs a mould. Thererore, evem in the case of an optical piclup device for a high deksity optucal sisc, in ir preferable to usr a plcstic oens as an lbjective lenr fpr the same reaxous.
However, for realizing an objectuve lebs wherein a high iumerical apcruure NA of 0.85 hws been realized whimf secoring sufficiemt manufacturimg tolerance
Field of the Invention This invention pertains optical lines and particularly to an control microwave amplitude and is applied to individual tap in a fiber optic delay line. 2. Description of the Related Art Fiber optic multi-tap delay lines in a developmental stage for electronic applications. Multi-tap delay lines split a optical into paths are relative to each other, modulated in amplitude and phase, and then recombined. The term multi-tap delay can also refer to transversal filters since they be used to implement impulse response (FIR) filter designs. to technologies, such micro-strip lines, optics offers some advantages such as lower loss and significantly higher bandwidths. Current fiber optic delay lines use a radio (RF) signal modulate an carrier, using directly modulated laser. carrier is then split into multiple (taps), each tap is then separately detected and Single sideband vector modulators may then be used modify the RF spectrum of each tap before is recombined. The electrical components to detect, modulate and combine the taps is fairly large and high in power The present invention to optical device, optical information and reproducing apparatus and an objective lens. Following upon recent high of an optical disc, a demand for a smaller light-converged a aperture (NA) of objective lens used for for high density optical discs high. example, of high optical disc employing a semiconductor laser light source having λ of 405 nm, numerical aperture NA of about 0.85 is needed achieving high density. Further, for objective lenses as CD (compact disc), MO (magneto-optical disc) and DVD (digital video disc), plastic lens used for the reasons that the plastic lens light in weight, and can be manufactured at low cost on a mass basis injection molding employs a mould. even in the of an optical for a density disc, to use a plastic lens as objective for the same reasons. However, realizing lens wherein a high numerical aperture NA of 0.85 has been realized while securing sufficient
 Field of the Invention
This inVention perTains GenEraLlY to oPticAl delay lines anD More Particularly to an opticaL delaY lINe whERe ElectRo-opticAL cONTroL oF mIcrOwAVe AmpliTudE and phaSe is applieD to EaCh individual TAp In a fiber opTic Multi-tap delaY liNe.
2. DescRiPtiON of thE ReLated art
FibER optic Multi-tap dElAY lines ARe in a deVELoPmenTal stage for electrONiC Applications. MuLti-tap DeLAy LINes SplIt a optical SiGnal iNTo many pAThS WHIch ARe delayed relaTive to each oTHer, ModulaTeD in AMplituDe and PhASe, aNd then recomBineD. The term mUlti-taP Delay liNEs can alSo refeR to TraNsveRSaL fIltErS SinCE tHey CAn bE used to iMpLeMent fInitE IMPUlse ResPonsE (FIR) fIlter designs. COmpAred TO otHer teChnolOgieS, sUch as Micro-sTrip dElAy lines, fiber optIcs oFfers some DisTiNct AdVantaGEs such As lOweR loss anD signifICanTlY HIGhEr bandwidths.
CurrenT fIBEr Optic delAy lineS UsE a RAdio freqUeNcy (rF) siGNAl to aMpliTUdE modulatE an optICaL cArrier, tYpIcally UsIng A diRectlY ModuLated lAser. The oPticaL Carrier is then sPLit into multipLE fIBEr PAth lEngThs (taps), each Tap iS Then SepaRAtEly DEtectEd and ReCOmBIned. Single sideband oR vEctor mOdulaTors may then be Used to modiFY THe RF specTrum OF eACh tap before it iS recoMbined. The eLEctrical CompoNents to dEtect, moduLATe and comBinE thE taPs iS FAiRly large in sizE ANd hiGh In power ConSumptioN. ThE prEseNt iNvEntion relAtes to an OpTiCaL pIckUp devICe, an optiCaL inFoRmaTion rECordinG and rEproDuCiNG apParatus ANd AN ObjeCtIvE lenS.
FoLlOwing Upon REceNt high dEnsity of aN opTIcal DiSc, A demand For a smaller liGhT-converged SpOt mAkes a nUMErical apErture (NA) of an objective leNS used foR reCordiNg/reProducing For These hIgh DEnsity OpticaL discS tO be HIGh.
For EXAmPle, In The case of a HIGh dEnsitY oPticAl disc eMploying a violet semIConDuctor laser liGht SourCE HaVinG WaVEleNgTH λ oF 405 NM, an objective lenS having imaGe-SIdE numerical APerTuRe NA of aBout 0.85 is nEeded FOr achieVing high dEnsity.
FurThEr, foR OBjeCtive lenseS such as Cd (compact dISc), MO (mAGnEto-opTicAl disc) AnD DVd (digiTal vidEO diSc), a plAstic lEnS is maiNly usEd For the reAsons that the plastic lens Is lighT in weIghT, and it can Be mANufActured at Low cOst on a mass ProDucTion bAsiS ThrouGh inJEcTioN MoldiNg thAT employs a MOuLd. THEReFore, even in tHE CAse Of an oPtiCAl pickUp deVice for a high densiTY optical disc, it Is prEFEraBle TO use A pLastic lens as an ObjEcTIVe lens foR tHe same reasoNs.
HoweveR, fOR realIzing aN objecTive lenS WHeREin a hiGh nuMerIcal apertUre nA OF 0.85 has beeN rEaLIzed whIle sEcUring sUfficiENt maNUFacturing toleranCe
 Field of the Invention
Th is inventi on pe rta ins  g ener ally  to optical de l ay l ines and more particul arlyto an o p ti cal d elay li n ew h ere  e le ctr o- o pt icalcon trol of  microwave  am pl itude and ph a se  is applie d t o each indiv idu al tap  i n a fiber  op tic m ulti-t a p dela y line.
2 .D escrip t ion oft h eRela ted Art
Fiber opt i cm ulti-tap delay  lines  a r ei n  adev elopmental  s tagef or elec t ro n i c  ap p lications. Mu lti-tap del a y l ines s pl ita  optic al si gn a l i nto many pa thswhich are  delay e d relat i ve to e ach ot her , m odul a te dinam p lit u de  an d  ph ase, and  t he n rec ombi n e d .  The  te rm m ulti- tap delay lin escana lso  refe r totran sv ersal  filte rs si nc e they can be u sedto implem ent  f ini te  impu l se res pon se(FIR) f ilter d e sig ns . C om pared to other tec hn o l og ies, suc h as m i cr o- s trip del ay  li nes, f iberopti c soffers s ome di s ti nc t advan ta ges su ch  as  lo wer l o ss a nd sig nificant ly hi g her bandwidths . 
Current fibe r  o p t ic dela y l ines use aradi o  fre quen c y(RF )  sign al to  a m pl i tude modulate an op ti cal ca rrier , typically u sing a dir e c t ly modul ated la s er. The optica l car rier is th e n splitintomultiple  fiber pa t h  lengths  (t aps ),eac h ta p is then sep a r atel ydetecte d a nd reco mbi ned . S ing le  sideband  or vect or  m od ul ato rs ma y  then be  u sed  t o m odify the RF  spec trum  o fe ach  tap be f or e it i sre comb ine d.  Theelec t ric al comp onents to  de t ect,  m od ulate a nd combine th etaps is fa ir lylargei n  size an d high in power consump t ion. Th e p resen t in vention r ela tes to  an optica l pick up de vi ce, a n opt i c al  in fo rmation re c o rdi ng an drepr oducing  apparatus and ano bje ctive lens.
F oll owin g up onr ec e nthi g h d e n sity of an opti cal disc,ad em and for as mal le r light -conver ged s p ot make s a numer ical aper tu re ( N A ) o f an objec tive len s used fo r  reco r di ng/re pro ducing  f orthese  highd ens ity o ptical  d iscs t o behi gh.
Forexample, in the case of  a hig h den sit y optical  di s c e mployinga vi olet semic ond uct or la ser light  sou r ce  ha v ing w avel e ngth λ of 40 5 n m ,  a n objective l e nshavin g i m age-si de n umerical aperture NA of about 0. 85 i s nee ded forac hieving high d ens it y . 
Further ,for objecti ve lense ss uch a s CD ( compac t disc) , MO (magne to-o pti cal disc)  an dD VD (dig it al videodisc ),  a pla stic l e ns i s mainly used forthe r e a sonst hat  thepl astic l e ns i s light in  weight, an d it c an b e man ufactur ed  at lo w c os t on a mas s  producti on ba sis thr ou gh i nje ctionmold i n g tha t em pl oys  a mould. T he r ef or e , e venin th ecase  of an op t ical pic kup devicefo r a h igh de n si t y  optical d isc , iti s  preferabl e  tou se a pla stic l ens as  an obj e cti ve  lens f ort h e same re asons.
Ho w eve r,  for  realizi ng  anob jec ti ve lens wherein  a highnumerica l apertu reN A of 0.85 h as  been realiz ed wh il e  securi n g  su fficien t  ma nuf act urin g t oler a nce
 Field_of the_Invention
This invention pertains generally_to optical_delay_lines and_more_particularly to an_optical delay line_where electro-optical control of_microwave amplitude and_phase_is applied to each individual tap in a fiber optic multi-tap delay line.
2. Description_of_the Related_Art
Fiber_optic_multi-tap delay lines are in_a developmental stage for electronic_applications. Multi-tap_delay lines split a optical signal into many_paths_which are delayed_relative to each other, modulated in amplitude and phase,_and then recombined. The term multi-tap_delay lines can_also_refer_to transversal filters since_they can be used to implement_finite impulse response (FIR) filter designs._Compared to other technologies, such as micro-strip_delay lines, fiber optics offers some_distinct advantages such as lower_loss and_significantly higher bandwidths.
Current fiber optic_delay lines use_a radio_frequency (RF) signal_to amplitude modulate an optical carrier,_typically using a_directly modulated laser. The optical carrier_is_then split into_multiple_fiber_path lengths_(taps), each tap_is_then separately_detected_and recombined. Single sideband or vector_modulators_may then be used to modify the_RF spectrum of each_tap_before it is recombined._The electrical components to detect,_modulate and combine the taps is_fairly large_in size_and high in power consumption. The present invention relates to an_optical pickup device, an optical information_recording and reproducing apparatus_and an_objective_lens.
Following upon recent_high_density of_an optical disc, a demand for a_smaller light-converged_spot makes a numerical aperture (NA)_of an objective lens_used_for recording/reproducing for these high density_optical discs to be high.
For example,_in the case of a_high_density_optical disc employing a violet_semiconductor laser light source having wavelength_λ of 405_nm, an objective lens having image-side numerical_aperture_NA of about 0.85 is needed_for_achieving high density.
Further, for objective lenses_such_as_CD (compact disc), MO (magneto-optical_disc) and DVD (digital video disc),_a plastic lens is mainly used for the reasons_that the plastic_lens is light in weight,_and_it_can be manufactured at low cost on a mass production_basis through_injection molding that_employs a mould. Therefore, even in the case of an_optical pickup device for a high density_optical disc, it is preferable to use a plastic lens as_an objective lens for the same reasons.
However, for_realizing an objective lens wherein a high_numerical aperture NA of_0.85_has been realized while securing sufficient manufacturing_tolerance