WO2007141598A2 - Système optique avec rétroaction cohérente - Google Patents

Système optique avec rétroaction cohérente Download PDF

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Publication number
WO2007141598A2
WO2007141598A2 PCT/IB2006/004287 IB2006004287W WO2007141598A2 WO 2007141598 A2 WO2007141598 A2 WO 2007141598A2 IB 2006004287 W IB2006004287 W IB 2006004287W WO 2007141598 A2 WO2007141598 A2 WO 2007141598A2
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Prior art keywords
light
feedback
optical
signal
detector
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PCT/IB2006/004287
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English (en)
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WO2007141598A3 (fr
Inventor
Aviram Sariel
Eyal Moses
Eyal Conforti
Shimon Levit
Javier Garcia
Yaron Hefetz
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Lenslet Ltd.
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Priority to EP06851253A priority Critical patent/EP1987410A2/fr
Publication of WO2007141598A2 publication Critical patent/WO2007141598A2/fr
Publication of WO2007141598A3 publication Critical patent/WO2007141598A3/fr

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06E—OPTICAL COMPUTING DEVICES; COMPUTING DEVICES USING OTHER RADIATIONS WITH SIMILAR PROPERTIES
    • G06E3/00—Devices not provided for in group G06E1/00, e.g. for processing analogue or hybrid data
    • G06E3/001—Analogue devices in which mathematical operations are carried out with the aid of optical or electro-optical elements
    • G06E3/005—Analogue devices in which mathematical operations are carried out with the aid of optical or electro-optical elements using electro-optical or opto-electronic means

Definitions

  • the present invention is related generally io the fieM of ⁇ puoai processing, for yxasuple, io optical proo ⁇ o ⁇ * such as vect ⁇ r-veetor-muitiplkfs or v-eclor-matrix-muItipHsjs employing eoiierem feedback for reducing readout shot ncsi ⁇ e,
  • a fan in optics collects the attem p ted Hght indicative of atuit ⁇ ikaltoa of the corresponding clemeiits of the finjt 3_xi vectors and likcctjj it to a f Smto deiecto?.
  • Althoiigli Oic light source used may be a coherent SOU ⁇ UO such ass s kse?, ihe light collection process is incchexent r ⁇ _» ⁇ Uliag in total light i ⁇ vcssity cqvu ⁇ l ⁇ o the susn of mtonsitics of sil cdlected beams.
  • Shot aoisc W proportional to the square-root of the ⁇ ismbor of detected ph ⁇ toa ⁇ .
  • any increase in accuracy by one bk means; slowing *knva the calculation by
  • I factor v ⁇ f 4 hereasing the light power by a ikcior of 4, or a conibi ⁇ atfos of both jc ⁇ ultsag in four fold increase is the mimbct of photons used for representing a re-suiting value- This s ⁇ w a limii on the accuracy and ⁇ peed of optical computers.
  • Sisru&r shot noise pjoMems are eueoimtored when desngnmg accurate t ⁇ ucai me&sirotne ⁇ t system*. Specifically, it is cHfiteult to measure a small change in s iaige opdcal signal. Shot noise tha& hinders increase of dynamic iaage of optical computers sad
  • tMs is ii ⁇ ed tn t educe ⁇ Isomoise.
  • a value of the measured attenuation is extracted from state of the feedback loop when light on said critics! detector is at or near minimal intensity.
  • the optical attenuator to be measured represents a result of optica! coosputatjon such as: positive or bipolar multiplication of scaiars or vector-vector aniifipiieaiioa
  • One potential advantage of the above exemplary embodiment of the invention is its i ⁇ uuiity to variation in the intensity of the. coherent light Since balance of the attenuation is the two amis of the interferometer resuUs m n ⁇ ftim&l or no light ⁇ H ihe ai least one critical output, large variations of the light source krtens ⁇ y have negligible effect o.a the state of the feedback loop mainurirarrg balance. Thus, small vanauon of attenuation values may accurately nsessisred in spite of large variation of the light source.
  • This fact enables cost reduction as susple laser such as diode laser may be useci withmn ⁇ be need to passively or actively stabilising the laser output.
  • the coherence length and/or intensity stability length arc selected u> snatch the optical paths.
  • ihe optical pa&s are rnodified so that fey are seat equal in length.
  • a IighL detector having essentially rum-linear respcmse i ' o light miensiiy may be used, as long as ⁇ ia signal, an said mon-iinear detector dimmishes as Iigrii intensity diminishes.
  • an avalanche photodiodc having internal gain, which makes is a fast and sensitive photo detector . may be ⁇ sed.
  • the- ircmt-end amplifier for the photo detector may fee mm linear or with limited dynamic range or even binary in nature.
  • the system and method according io exemplary embodimcnis of the current invention uses "null detection” in which, at the point of calculation result, the deisetor is illussinated by a "dark fringe" of interferometer, lhas the light level delected by the detector is minimal, zx ⁇ the shot noise is eliminated or at least minimized to a value set by dark current at ⁇ l parasitic light ⁇ xa to Unite contrast of the interferometer.
  • coherent light from a singis laser is divided mtotxvo branches: a computation (or branch: m ⁇ feedback branch.
  • Ltghi m tho computation branch undergoes optics! processing similar to processing used an optscra! processor* known in the ait. However, in contrast to incoherent optical f r ⁇ ccssors, phase of the light Is maintained.
  • IB a Vector Vector Multiplier (YYMX coherent light enters the eotapuiatkm kaueh where it is: a> Divided ⁇ aso ⁇ g a pturalstj of channels typically corresponding to the number of vector elements h) T ⁇ r each channel %ht is modulated such tliat the light field amplitude rcpro ⁇ eal-s tho cone ⁇ fxmdi ⁇ g vaf ⁇ e of ilr ⁇ t vector element. c) For «aeh chsmie! amplitude of the hglit ⁇ further jJttenuatcd by factor represontmg tts ⁇ corxespondi ⁇ g value of second vector dement.
  • the light ar ⁇ plstade represents the
  • ⁇ Vector Matrix Mult ⁇ bcr may be represented as parallel VVM of ⁇ iirst vector wiut plurality oi ' secoud vector; sm ⁇ seatxangmg the planets Iwm the VVM operation as athir ⁇ ⁇ cetotv Tn a ⁇ "MM. enhej ⁇ ii light enters the coiaputation braticl ⁇ where it is: ai Divided amtntg the K niput channels, corresponding to the immhct of finst vectoi elemems.
  • each output channel light is i krth«r attenuated by a factor representing values of the Ourrcipondmg ⁇ k, m] matrix olcmcni ⁇
  • rcpi «sseuts the multiplication of values of fi? ⁇ t and a Taairi ⁇ element e)
  • Light tioin all ehan ⁇ eis corresponding to tfeu same row in a matnx is oohcrenily sddsd iogcthci to foun an output optical signal vviih Held amplitude representing a third ⁇ ect ⁇ u ekmcta of the ⁇ ectQr-jsatrix multiplication, which is the result of VMM mathematical operation.
  • Ati irKsofaereal VYM or VMK! processor wherein output UgM k detected and digitized, hi a? aieihod according to an cxemplasy embodiment of the present mve ⁇ iioa.
  • a feedback mechanism su the feedback branch acts on the feedback light to creates mm ⁇ xml li ⁇ i iv ⁇ mu ⁇ ty - ⁇ t nn output of ihe mter&xvsmcter, by providing feedback light with field smp ⁇ tude but opposiu; pb ⁇ stc of the compsMiem bnuich light signal.
  • a feedback loop attenuator is ⁇ pi ⁇ ona ⁇ iv used for providm ⁇ feedback light with th ⁇ dcsked absolute value amplitude.
  • Correct phase of the feedback loop light is optiwially maii ⁇ lam ⁇ d by the nature of the optical mtcrCsromsteric syste ⁇ i s ⁇ id'Oi usisg a plia&e shitliug etsme&t ⁇ optionally controllable).
  • OpticmaUy a f ha ⁇ c jjblft ⁇ r m the feedback loop h used to ensure I&e correct ph%;c of the feedback light.
  • the Hghi is not coherent when processed, but made cohcnsm after prooe ⁇ slrig. tor example, usiiig ⁇ coheresu light source whose amplitude is dcte ⁇ rii ⁇ ed bv i ⁇ ispinging of mcohetx. ⁇ t light in the form of a power and/or a control signal
  • the feedback loop aad reedbaek signal are aaaiog. and result is oht ⁇ iued by digitizing said feedback signsl.
  • the feedback loop is a digital loop, ⁇ s ⁇ ag digital steps to update the feedback CO ⁇ HM J signal and the computation results are obtaiscd t ⁇ oai diguu ⁇ status of the teedbacl. looo. fc some of these embodiment, ihe digital feedback loop uses a "successive approxiiaalioa algorithm " whescin the sue of stops used S ⁇ cbangmg ⁇ i ⁇ ? feedback control by factor of two ; ⁇ each successive step,
  • ihe number of bits depends on the t Anlagen ⁇ d accuracy of ⁇ he computation snJ ssuy ckmgs depending on the context of the compulation. For example, ormcai computations may he f erformed ai higher accuracy than Jion critical computations ui ways similar Jo ⁇ e aso of "double precision" used ia ebctroaic computer, however any auKiher ofbit ⁇ sx&y be selected,
  • coherent Lglit processing b advantageously « ⁇ ed by using both amplitude and phase of ihe light field as way of cepa'smU ⁇ g a vahe.
  • k coha ⁇ ent hght sisnmatioa ⁇ he light's electromagnetic fields sre added as 2-D vectors.
  • field smphv ⁇ da is tdciuified by a cM ⁇ pkx number in a Cartesia ⁇ -s cocuxlinatss.
  • ai «pH ⁇ udcs of cump ⁇ «alio ⁇ result field aad feedback field mus. be an exact negative of sach other. That is exactly the same intensity, bat v ⁇ ilh ⁇ hcir phases opposite to each other.
  • vaincss Usod in the computation* arc uacorrdsied ⁇ t p ⁇ eudo-raudom.
  • A.ddiiionaliy s in many f ⁇ plica ⁇ o ⁇ values may be rearranged (or otherwise modified, for cx ⁇ mpk by adding a random value) ⁇ o en ⁇ re tmc ⁇ rrekte ⁇ or pscudo- random aal&rc of the values.
  • n may improve fee accuracy by allowing only Jhc Seid from the beams' osatcr Iu mter&ic O ⁇ the detector.
  • the sire of the aperture is s «s t ⁇ > matcfe fac error iolcmuce iCt ⁇ aired ⁇ nd'or p ⁇ or knowladge otstatktical prttpertics of the input v&ucs.
  • fiber optics tn ⁇ y be usea to te-$lupc a bca ⁇ ti * for example a s-mgk ⁇ ⁇ sr ⁇ 1e fiber may be use-tl Ca a » shapc the fevam ⁇ vi s aesr dif ⁇ rsctsoa bmit ⁇ auis ⁇ an siiapc,
  • beam shape mampul ⁇ ticn may he dose o& oao oj ' tfee buutches or v-w both sep&ately.
  • a Mach-Zehader int ⁇ rferomet ⁇ may be used uS ⁇ jt dec ⁇ ro -optical smwmre in its arm to modulate the light tick!
  • a poic ⁇ d ⁇ i advantage of using sniuterfefomeier as s moJuiat>n" is that unlike && absorptive r ⁇ odoktor, it may abo ⁇ issd to r ⁇ veae the phase of tbe beam to ⁇ opr ⁇ «iC ⁇ $ n-egative values.
  • the exee ⁇ light oxi ⁇ s the iBterfemmcter &n ⁇ do ⁇ s ⁇ oi produce heat that has to be removed from the sys»lem>
  • a pliase shifting dc% tee may be used for ai ⁇ ectmg the phase of the heats to represent negative or complex vslaes.
  • Imerteronicteis may be mna ⁇ factated using freely pwpsgatkg beam ⁇ vismg mirrors, lenses, lensk't*, beam-splitters nnd'or other optical elemctus.
  • O «xHttj ⁇ 2asifmal optical systems may be constructed, losing single-mode optical fibers.
  • polarizaho ⁇ maiau ⁇ tiing Obers are used. Beam shape of light propagating m such iihcjs is maintained and dcpc ⁇ ds.
  • Combination oi i- ⁇ , 2- ⁇ and 5-D system maybe «sed to construe t th «j desired optical system.
  • ooa ⁇ potie ⁇ is used m the system according to the irrvctttioa w> mipedeci.
  • ct «mp osents itsed as! modulators may have imperfect response,
  • a Maeh- ⁇ &hsxkr iuterferometer used as modulator has a response.
  • pre-pnscsssbg of computation values is used for compensation.
  • pu£t-proeesMS3g of eonspoiation results may be used for eoinpOKsation
  • ei ⁇ jboiimwtsJ of lhs as ⁇ alucs of input vector ekmeMs are pre-processed before they are uss.
  • ' ⁇ is a modulator ⁇ O aflbci ihs light field.
  • input v&kias such as values of ⁇ r ⁇ t ⁇ x elcmeais are pre-processe before they are used in a modulator io ⁇ f&ei the light SeM.
  • Analog or digital or combination of aaalog and digital may be «sed lor the preprocessing, post- processing orisctb.
  • i&m ⁇ varying are ⁇ optionally &$t.
  • detectors, drivers md mmluiatois B.sed m the feedback loop optionally react ⁇
  • binary electronics is faster and consumes i «ss power than Linear eleetromcs with comparable speed
  • binary circuits are used for driving elements such as a feedback loop modulator of a coherent feedback optica! computing system according to some cmbodane ⁇ is of fee present invention.
  • the feedback SeM optionally changes in predetermined steps of diminishing size.
  • algorithms similar to the- "slgma delta" algorithm may be used.
  • APD Avalanche Photo-Diodes
  • the signal io be detected is less than 30%. less ihan 20°/ «, less than 10%, less than 5% (or intermedials values) in ampiiiude of the signal w be measured before intcrfercsace.
  • the range of the signal to be detected is less ⁇ nm 30%, less Shan 20%, less than 10%, less than 5%.
  • ⁇ ntpliiudc of the sigi ⁇ til io be measured before mterf ⁇ re-nc ⁇ .
  • ihe shoi «oisc* goes down by a factor of at le&jt ! .2, 2, 3, 4, 5, 10 or intemicdiak: values.
  • U jshosld ho ⁇ oted that a singh systens may include two or snore diiTwnt measurement ciremis. for esample ⁇ one using an mtcrfsarometric tcdjaiqiie $s described herein (c.g« for large valaes) and fee other usiag a standard or other type detector (e.g., for low values or if Um mterfcrom «tdc technique fails, fov example, due io over-coi ⁇ e!atiou of isiputs.
  • & mcasuf tfment $y$tom having coherent feedback is provided.
  • the sy& ⁇ m according to an effibodi ⁇ vont of the iavctuion uses ⁇ coherent feedback loop to increase speed ui ⁇ ht accamcy of the measurement in optical measareended systems used ia die art, a transducer Is used to generate or Bjodabttf a Light signal indicative of the measured value. This signal is then detected with a detector that converts the light to electric signal, which is usually digitized.
  • s beam splitter spUrtmg Ught from jjaki coh ⁇ e ⁇ t HgM :>o ⁇ rc ⁇ to a measurement branch and s feedback hru ⁇ cts; at least oac trafi-iduecr modulating li.uht in the raeaj»memeju branch to indicate ⁇ se ⁇ urcd value; at least OBO uiihi mcdulaior modulating light m the feedback branch: at least one tatcr ⁇ ror ⁇ ele* tor interfering light fe> ⁇ the measurement branch with light from the feedback branch, ⁇ t least one light dciceior dciec ⁇ ng light from dark fhngc of *a ⁇ i ititerioromotet . and a feedback loop, contruHmg h ⁇ t modulator at the feedback branch m rc-spon ⁇ o to signals from said ⁇ t icast one light d
  • the tratisdiicor modulates tiic intensity of light ia the me ⁇ 5suremom brauch atifl meastired value is fefesred from sntessity s ⁇ ts feaib ⁇ ok Ixgh? wh ⁇ n ileM fiinpljr ⁇ d ⁇ * in meaxajemc ⁇ t branch and moasaned aad feedback branch arc e ⁇ iiiai,
  • a feedback loop is used to track ⁇ ie changes m the external system to be measures mid a sample and hold is used to sample the state of the feedback signal.
  • high-frequeticy modulation is imposed osi die feedback S ⁇ gna! and irf used for the tracking.
  • Figure 1 depicts a .simple optical xmili ⁇ pHer as knovt'n sn the art
  • Figure 2 sofaumatioaily depicts a 2x2 optical V ⁇ cior-Vcctor MulupUtir (VMM) as known in the an
  • VMM V ⁇ cior-Vcctor MulupUtir
  • F i gure ⁇ Schematically depicts a coherent feedback optical tmihinlier according to an. embodiment of the current invention.
  • Fig ⁇ r « 4a Jcpic ⁇ >. as optical multiplier using a binary feedback loop according to an.
  • Figure 4b depicts an optical multiplier using a digital feedback loop according to aa erakxlimem of the eu ⁇ ent invention
  • F ⁇ gtue 4c deraetsi su ⁇ tteal inuitiplier adapted for handling, bipolar ⁇ aiues according to au exemplary embodiment of the invention
  • Figtuv 5a epicts an optical computalioa sy&iem witij & coherent signed feedback loop aecordtng to naoiher aspect of the current invention
  • Figure 5b depicts -iu optical coiapulation..system with a coherent ⁇ nsdbitiary feedback loop according ir- an embodiment of ibc current invention
  • Fipfc 5c depicts m optical computattoa system with a coherent signed feedback k ⁇ Kce ⁇ rding TO yet another sspect of the current ia ⁇ cation;
  • Figure 0 depicts a sehcmatio block diagram ola eoiaputational branch of ait optical
  • Fsguvc ? sohematiesllv depicts a block diagram of a computaftoas! branch of ao optical VVM using beam !>
  • Figure £ depicts a sekoma ⁇ c bioek diagram of computational braiioli of as optical VVM using len$es for sp lilting m ⁇ eombinkg beams scc ⁇ rdmg to sn embodiment of the current kivont ⁇ O ⁇ ;
  • Figure ⁇ schematically depicts aa optical VMM hoving a coherent feedback loop according to ,J ⁇ exetr ⁇ imy eajbodinjem of the current invention:
  • Figure 10 depict? a schematic block diagram of a measurement system a ⁇ -tsg c ⁇ hercat feedback accotding Io an exemplary embodiment of the current invention. asx!
  • £igu*e 11 depicts a schematic block diagram of a measurement syUerr* us ⁇ sg coherent feedback csp&hle of measuring both attenuation and phase shift according io m exemplary f ⁇ shHlatir ⁇ t olthe current invention.
  • Jt i? io be lisjderstocd Lku ihc invention is not limited iaits application io tbs details of oonstKfet ⁇ on and tfe aiTunger ⁇ nt x>t the ootspontsnls set forth in the follow mg deseriptimi or ⁇ lustmed in the d ⁇ nvmgi ⁇ .
  • the invctstio ⁇ is? capsbb of other embodiments or of being practiced or earned oat in various ways ⁇ Lo. it u to be understood that the phraseology axi ⁇ tera ⁇ m»iogy employed hereui is &n ilic purpose of description and should not be regarded as limiting.
  • Hie ⁇ -a ⁇ i ⁇ gs axe gene-tally aot Iu scale. for clsriiy. Bon-eksentiai elements were omiti ⁇ d from souio o ⁇ ths drawmgs. Ai « us «d heteia, &n e!ome» ⁇ or ⁇ tep recited its the siogubf a»d proceeded with the wot J s V or vv 3 ⁇ r should bo understood as aot excluding pluial elements or steps, UGicss ⁇ uch exclusion is
  • Figute I depicts a simple optical oiuinplkr UK> as known us fee art.
  • Input light 102 emitted froai light source 104 caters the optical multiplier which comprises of tv* ⁇ light ifficusrty attenuators 10(ja and 10(A situated along the op ⁇ eai path of ixrput light 102, in the sapletaematioss used in the art, light, source 104 may emit either coherent or meohcrs ⁇ ? r&diaiion.
  • intensity attemialo ⁇ s 106a and 106b are efc ⁇ roakaJIy controlled by electronic derives ⁇ i)U& m ⁇ 108b respectively sack fuse that the.
  • ⁇ & ⁇ &n ⁇ Tr ⁇ asxmssk>n are the i ⁇ msmiita ⁇ ce ofaUenuaiors 106a and 106b respectively;
  • Arbitrary is an arbitrary coefficient, which depends on system consu ⁇ ction;
  • Exit light 110 impinges ors a light detector 112 and is converted to an electrical signal pmporiional io the i «tensity of the exit light.
  • an Analog Io Digital Convener ihDC) 114 OGx$v «ris the dectdcal signal frotn Hghl detector 112 to digital form.
  • FIG. 2 scheasaticaUy depicts an optical 2x2 Vector-Vector Multiplier (VVM) 200 ; ⁇ s an.
  • VVM Vector-Vector Multiplier
  • Inp ⁇ i lighi 202 emitted from a light source 204 is split to two branches of equal intensity 202-1 avid 202-2 by beam splitter 205,
  • Light of sack branch passes through an optical l ⁇ ultiplier which comprises two Sight intensity Multiplier I comprises attenuators 206a 1 and 206b 1 , wfeiie multiplier 2 comprises atle ⁇ uators 206&2 and 2G ⁇ b2.
  • Sight intensity Multiplier I comprises attenuators 206a 1 and 206b 1
  • wfeiie multiplier 2 comprises atle ⁇ uators 206&2 and 2G ⁇ b2.
  • two tttul ⁇ plkrs are shows, however fte number of xmd ⁇ iir ⁇ may be larger.
  • light source 204 may ejri ⁇ t either coherent or incoherent radiation.
  • intensity aitcimaiors 206 am aketromcally controlled by decitonsc delivers 208 such that ihsi the transparency of each attemiator is proportional to Xhz co ⁇ resptmdi ⁇ g numerical values 209a! , a2, bl
  • the system may bo extended to larger dimension vectors by creating as many channels as the dimensionality otihc vectors. Extension of ihiss type of system to a Vector-Matrix Multiplier (VMM) b known in the art " .
  • VMM Vector-Matrix Multiplier
  • VMM vecmr raauix multiplication
  • analog eJccU'Ome vector matrix multiphea ⁇ oamul is described, for example, in "Programmable ⁇ aaJog Vcctor-Mairix Multipliers", by F. Kub, K. Moon, L Mack, F. i..o ⁇ g, in 5 BEE Journal of Solid-State Circuits, vol. 25 C ⁇ ) pp. 207-214. 1990, which is incorporated herein by roiVrence.
  • the optics! systems aad methods according to some embodiments of the current mvetuion operate wkik the optical iatessity on the critical detector (or criCical detectors) is rornsmai or > ⁇ ttu!Iy trull ⁇ p ⁇ testkl advantage of ⁇ x ⁇ » is* that the above himutUtm may be overcome.
  • ⁇ system sccotdujg to as exemplary embodiment of the mvcnuos uses a coherent & ⁇ &Ua ⁇ »U%$ * ' interference between light beams: the first be ⁇ na vcpresenCmg the value to be measured, for example the computation result: and the second beasj ⁇ s generated ana comtolled by s Feedback loop.
  • the first and the second beara ihe hght intensity at the outpm is ⁇ st n rm ⁇ ima and Uw noise associated WHk its detection is small
  • the nKmurod value is safened ixom the ieecback loop CHci ⁇ tjy.
  • Cohcrsmi mrui ligbj.302 oriHied fro ⁇ i a oohsirent light source 304 is spht ;o m r o pa ⁇ ?; a eompumtioa chanaci input beam 3UX and a feedback chaimei mptH beam 302V by be?«n ssphttcr 305
  • AsipMade sttenuaiois 305 ate cbcironically coMrolkd by elscirOBio dcs.t ⁇ c ⁇ 3 ⁇ 'H s?uch ti ⁇ at that the ampiiuiJc tjansparctjcy of each attenuator K pioponi ⁇ ai w a uunseiicai vsi ⁇ cf. " «" m ⁇ b' 1 to be muiuplwd i ⁇ t ⁇ * ⁇ m ⁇ ,1 30% respcctivsly),
  • a coherent detection umi 325 controls feedback smpli ⁇ ide attemsator 306f so that ⁇ l ⁇ output 315 is obtained when amplitude of computational channel exit HgM 3 IOC is equal to amplitude of feedback channel exn HgIn 310F.
  • amplitude transmission * T * ⁇ f smpli ⁇ ude attenuation ol attenuator 306f is equal io the combined amplitude transmission of attenuators 306a and 3 ⁇ b, thus f TM a*b
  • colr ⁇ r ⁇ n detection unit 325 compares at teasl oae beam &pUticr, When two baams enters, a beam splitter, an iuter&aenee ooctns between the tvtc* beams $uch feat at o ⁇ o exit of tho beam epluter ihc Iigbi OeId amplitude is the sum of the amplitudes of ihc two inccmmg b ⁇ as ⁇ s, whiles ir? the other exit light field amplitude is the difference of the amplitudes of tbi two mcomi ⁇ g beams.
  • coherent detection unit 325 comprises a beam splitter 311 receiving computaticmaiL channel exit light 310C and feedback channel exit iigin 310F.
  • a bright fhngc is marked by fall heavy arrow, while dark frmgo is xnar ⁇ «£ by a dashed heavy gm>w St ⁇ tmg fb- i example with iaput light 302 v, ith intensity of 2,0 (arbitrary ui ⁇ u) or field of 2i) ⁇ usmg a 50:50 h ⁇ &m sphuss Si)S tlicre is m cq ⁇ al field amplitude of LO ⁇ arbitrary ⁇ mts) at Uw input of each of channels 3OX' ⁇ ad 3O2F. After passing through the attenuators in each cluoBOl.
  • Feedback io ⁇ ic 32O r «ceis'es*igmU irot ⁇ detector 312 and controls alternator " ⁇ ) ⁇ f ihtovish driver 308 in order to achieve ihe baiasc ⁇ coaditioa whiSi output 315 is chiasms!
  • uie emb ⁇ dli ⁇ usm feedback logic 320 sweeps or ⁇ mips (hrougb possible s alues of C & ⁇ ⁇ cGgtn/u ⁇ s tl ⁇ o Blest hk ⁇ ly ⁇ aius of f thai creates null signal ai detector 312
  • ADC 314 fusy be a ⁇ gger at the uixie during the sweep %l ⁇ &n Mgaal of detector 312 is below s sm&H preset tlueshoid Is another es ⁇ bodjr ⁇ ent feed bad logic 320 searches through possible values of f for a value that tn ⁇ mm/es the sigm ⁇ of detector 312 For example.
  • tnmsmiyaUon raeU ⁇ cts described in "'Hixmrnm ⁇ Rec-jpcV (William H, Pi ess eiai, Cambridge University pi ess, Ctepte ⁇ i ⁇ page ⁇ 274-27?) may be used, ⁇ i sbouM be noted that sigm ⁇ l on the detector is a concave hmcU ⁇ a of ihe ina* value for f, zix ⁇ ⁇ sisgk ⁇ nhnum cxi5>U> and w eassily found ⁇ n fact, in sume ci&ev this f ⁇ euoa it» appjoximatelv pa ⁇ olic. allowing methods opamizcd lor such a shape to be used
  • numm ⁇ ii dark lrsngs may be ⁇ ch ⁇ e ⁇ «d uh*s ⁇ f C* a*h ⁇ herc C is some numerical c ⁇ n ⁇ t
  • Figure 4a depicts an emhodii-o ⁇ ni oi a binaty feedback loop variation of the optic ⁇ truitipher of figure 3 in whwh s ⁇ alog coherent detection unit 325 « replaced v- ith a bi ⁇ arv- eoherest dciection ua ⁇ t 425
  • ⁇ pulse geaeiat ⁇ r 430 produces pultses at high rate.
  • hi operations aa analog aci-'uinulator 420 aceimiui ⁇ tos tho charge m the pulses ii ⁇ m pulse ⁇ eaef &tot ⁇ 3 ⁇ , civais ⁇ g a ratup analog voltsge whien is received by analog dm er 30Sf
  • a digsia! ⁇ ccam «ktur 418 accumulates (counts) she pulses gcnei ⁇ t Rg d jgjial sufsbci ⁇ j.>i$s5 ⁇ tal: ⁇ *; of f.
  • Tiiis vsah ⁇ dhmeut is l ⁇ scd ibt 4e«i ⁇ iistratiag S ⁇ impl ⁇ ffientat ⁇ >a of bki&ry feedback loops? aocofdasg to some embodiments of the current fcivea «o» ft should be noted ikn the ⁇ urabsr of cycles may needed to r ⁇ seh the final v&luc may be large. Additionally, there is a danger that BOXSC on che dctecior or comparator may cause the loop not to close as fee threshold may not " be crossed if the ftoise is aecideutaliy above the preset threshold. Additionally, She ncemacy ts limited by the comparator pje ⁇ ci thieshold valine.
  • Fsgisre 4b depicts an embodiment of a digital feedback loop variation of the optical multiplier of % «re 4a in which the binary coherent detection unit 425 is replaced with a digital coherent deieoUoa imit 455,
  • a digital ramp generator 460 produces digital ramp value which is received by a digual d ⁇ «r 40Sf. near s ⁇ etx ⁇ threshold value.
  • Figuiv 4c depicts an optical multiplier 400 adapted for kuidli% bipolar values gceordmg to as. exeisplary embodiment of ⁇ ic invcation, Ui ih& embodiment, a t>base shifter 306' JS added m line whh each aiteauat ⁇ r 30o. fin a commutation b ⁇ tnch 4S()C ⁇ phase ihiftets. 306'a and 3(HVb were added in Hue with mtessttRtois 30 ⁇ a u «d 306b respeeuveiy. ⁇ t should he no ⁇ d that the order of attenuators and phase SfKiHe...
  • Phase shifters 3(V receive from 308 signals Isdicativc of the sig? ⁇ ofthe (positive i»r ⁇ ?gMivc) end afibci a phast; shift of IHO degrees accordingly.
  • AitomativaK. only o ⁇ c phase shifter per jm ⁇ tiplleatson channel m&y be installed ir>. (h ⁇ computation branch, asd h$ status determined by ihe combined signs of the two values to be mu ⁇ &plkd.
  • the siga of smgle multiplier result may be determioed electronically by the cotabmad signs of the two values to be multiplied and presented together ⁇ * Uh the of the result Howev ⁇ i, as ⁇ hatl be ⁇ !e. ⁇ ioastra.ied Mtw, wJisai the c-osipuiation brcmch cot ⁇ spiises r ⁇ UJplc cha ⁇ sels ⁇ bi perforrnmg more complex operations ⁇ uch as ⁇ X ⁇ , the us? of at least one phas£ shilki per ckmncl to reprssscnt bipolar valoes curs ha udvantag ⁇ us.
  • Figure 5a depbu. ss optics! oamputauos system with coherent i ⁇ ig ⁇ ed feedback loop 5 € ⁇ ) secordisig to another aspect of the currant invention.
  • ⁇ dia ⁇ back of minima searching algorithm is that error signal pcod ⁇ cMby the detection swtem and usicd by the feedback loop do not eoatain iafbittiaiiou an ihs dtreciioa in which to change the trial va ⁇ us. DirecUouai information ts gathered by successive "trial and error' " stc
  • Systera 500 comprises thteo sub units: s computation branch 40BC: an * >f t ⁇ cal i ⁇ >tct fem:Betcr 502; aad * ⁇ ssgaed feedback loop 501,
  • Optical bnedemmeter 502 receives, input light from cohersM light ⁇ aurce 304 and produces at kasit v&o opdcal oulp «ij ⁇ 523PD mi ⁇ 532ND to be used by signed feedhaek loop 501 to puxluc ⁇ a signed sigr.a! for closing the loop.
  • Optical ⁇ iierfc ⁇ moier 502 b constructed such ⁇ ni st least both optical outputs are at or nc&r ?cro optical stgnal when ike ir ⁇ erlerotietcr ts balanced.
  • optical interferometer 502 comprise? a pickoif beam splitter 520 spUtlmg a small amount of light m the form of a weak bias beam 5026 from input beam 302. The majority of the light exits pickoi ⁇ b ⁇ am splitter 520 as main. ⁇ tipxit beam 5 ⁇ 2.
  • Baom ijpliu «r 505 splits rnaia input beam 502 to computation input beam S02C and feedback in ⁇ i beans S02P,
  • Computation channel exit light 510C is SfI it w two equal beam* 5 JOT * b ⁇ a beam sphtter 522- ⁇ i ihtt feedback chsuaeL feedback liranch 4S0F aCfccis tlw beam producing fce ⁇ back channel CX ⁇ light 5 Wi ⁇ &r ⁇ t$ beam 5O2d i ⁇ ititorfercd wUh feedback channel CM* light 3 ⁇ OF si Desm sjplitrer52] pixxkicmg nvo slightly unequal beams: Pssithe Feedback beam 51 OFF and Negative Feedback SIt ) FN depending on the sign of the field jnterfereace atbcsn? spliitcr 521.
  • Bear ⁇ 5 IOC is equally split to two identical b ⁇ sms 510C each having a ⁇ ppmask ⁇ f
  • beam 523PD has the amplitude of
  • beam splitter 523R beam 523PN has the amplitude of:
  • S 14 may be triggered vain® the feedback loop has iseftk ⁇ , for example by observing a stnali signal at Uic output of ⁇ tTerenisal amplifier 520, or it t&sy be U ⁇ ggefoJ St preset USBC or presei number ⁇ f cycks? depending on ths? desired accuracy after aew values of a and b were mput at the eompxitatso ⁇ branch 4OJ5C
  • 5b depicts an optical compa ⁇ atiun ssvsicm 570 w ⁇ h. » eol ⁇ erent signed binary feedhaek i,r ⁇ according to aaoihcr embodiment of flic cutTent inv ⁇ ittoit.
  • Binary comparator 530 compares ifec signals of dct ⁇ -ctojs 5!2P and 5I2K producing a single ⁇ ni equal to either > 1 or -1 depesxlmg on which signal is larger.
  • feedback loop is reset to a preset value after ihe cempletjojn of s computation pnx'ess
  • the pi ⁇ set initial value k at mid-range.
  • the ssz « uf ibe step depends o « the tuagmtudo of the dit ⁇ rcaee &g3Ul ⁇ % ⁇ £ two d ⁇ t ⁇ clors. as ⁇ kte ⁇ ti$ned by the difference of the S ⁇ g ⁇ sls of the ⁇ * O comparator ⁇
  • Opueal mterfoi ⁇ metei 602 compnses of splitter 505 splitting the light of input beam 302 tp die eoa ⁇ putatioeal br«ftcli408C a «d feedback branch 40SF.
  • feedback hzmxch 480F (computing an atten ⁇ ato? and opttonaliy a phase sMtor) affects the beam producing feedback channel etit light 510?.
  • tlio dUTereacs 1 bel ⁇ oea the ⁇ sgnsis produced by ⁇ eieousrs, we v&rt witli po% er al ooh «sont sourct; ⁇ f2.0 m &ontc arbttrarj' mtcus ⁇ t>" ⁇ niH.
  • Besan 61 OFF has ing amphtode oBr*P ⁇ B-#, and Bea ⁇ n (>1 OFF h& ⁇ i ⁇ g ; ⁇ « ⁇ U ⁇ «do of Yi *"f*(1 -d ⁇ -
  • beam 623?D has ⁇ ic amplitude of: v> ! l *a*!>S s *f*(l fd>; while iU ike dark fringe output of brain splitter n23K 5 beam 623 PN has the ⁇ mplittsde of; J //'*a*b-lj *f*(l-d).
  • the power on U ⁇ tector 512P is gtven by v,'- ⁇ *h-// ⁇ f ⁇ ! 1 Cl)F •- ⁇ ilanviy ⁇ d'f « i » ⁇ D-PM 2 s whew D - ⁇ a*b-i denotes the difTer «uo « beuvefen Xhc computsttoa value a*b and the feedback value C
  • the power o « detector 512?, given by VHPd)" is small when f - a v b.
  • the power on defector S12N is given by: >V»a v b- 1 ': N f*(1 - ⁇ f « * ⁇ ta*£K ⁇ U*df - 'VH_Hf*df Thcpov ⁇ on defector 5CN, given b> 5 Z ⁇ (PtIr is small when f ⁇ a*b.
  • a pickup beam splitter (liot ⁇ hown) picking sosic of the light from computation ehanxieS cx ⁇ Ught i ⁇ IOC ⁇ v&i directs t ⁇ to a dueet iseaswome «t photo detector (noi *ho ⁇ vn) ituiy Iv «$e ⁇ Op ⁇ nssliy, if ssjgntsl ⁇ n direct m ⁇ a ⁇ iiresient photo detector is beiuw a pteset value, ⁇ U> signal is « ⁇ >ed for ⁇ etemHU ⁇ ng IMc result while if us signal j « * above A preset valtis.
  • sigaai from the feedback loop ⁇ «J «SC»3.
  • IB digital feedback loop 601 epioteu JK the embodiment of %ure 5c.
  • a ⁇ soNt d ⁇ gm?cr 624 digitizes the analog ⁇ lgn ⁇ l ⁇ un differential amph ⁇ er 520.
  • Figure 5 ie-pkisS a schematic block diagram of a compatatiosal branch 4SO of mi optte&i VVM u ⁇ i ⁇ g coherent feedback according to an embodiment of the current t ⁇ vent ⁇ otiu box simpivzity, input xectois aye shows as hax ⁇ ng two dements.
  • IK the example of Sgur ⁇ 6.
  • ihe tipper channel is affected by hvo attenuators; 60 ⁇ al aad 606b 1; while the lower channel is af&cied by uvo attenuators; 6Q6:t2 m ⁇ 606b2,
  • Coherer * ! beam coaabmor 611 coherently combine the two ohaa ⁇ els to produce « computational output beam MdC with amplitude proportroual to al*bl-&2 ⁇ b2.
  • Ths optical system is ⁇ xtcsided to higher dimension vector by adding more ehan&ds ⁇ o the csalci ⁇ latioa branch. Exemplar)' embodiments tor such cxteas ⁇ oa are depicted in ⁇ he felloe ⁇ ng figure.
  • Figure 7 sdiemaiic-aliy ⁇ L*piet_> a block diagraro of a cor ⁇ puvatio ⁇ ai bniach 480 of an op ⁇ cal VVM using beam j»pUuers aceordi ⁇ ig to an embodiment of the cunvsnt
  • Oo ⁇ putauoa canael input beam 302C is successiv ⁇ ly split to two equal beams by a plurality ni " spliters 71 1 , ibmusg N * cha ⁇ nds wlicre IN (S ⁇ 2 ia tbis exa ⁇ sipie) is the & «mber of k*vcls ⁇ ofspiUtis%.
  • Each beam is aikcujd by tw ⁇ ⁇ n ⁇ d ⁇ latQis.
  • Ia the ⁇ gure " ?, light in first cbiai ⁇ d is atYected by modulators &l and b! , second ehaxujel by modulators a2 and b2, ate.
  • Coherent eombiuiisc of ibe beams from ail channels is ⁇ Q» « with successive addiiioas nf ihe biiimi amp liiudcs using beasi splitters 7 LI .
  • a bright fringe is selected trcr ⁇ ibe miederei-ce on beam j»phttsrs 713 to produce a computatioaaS outpui beam 310C wl& a ⁇ iiUKic proportional ⁇ > al*bl • »a2 t l ⁇ +a3*b3' ⁇ -a4*b4- i. srg%;r number of channels the number of levels of spiiaing. it should he noted thai uaswidsbiy some of ihc light intensity IM lost through the dark fringe oiuput of the combining beam splitters 713,
  • ⁇ compact system maybe consuucled by tJsmg a mmiaturo free space ptop&gstmg beam. ⁇ he» ⁇ « ⁇ th'ely ⁇ fiber optica taay be tisod for coustructiag the optical comporsaus. ⁇ itc ⁇ v ⁇ tively, optical curaponentii may be Hthographleally produced cnt tliia transparent turn,
  • Confutation esu&oi input beam 3O2C is split to N equal channels by fas out optics Sl 1 -
  • i&n out optics Sl 1 comprise? tv-o lenses, t* beam diverging km! &1S and a eoFhmatmg fens 81&.
  • a ien&let array is used to assist the coHi ⁇ naiios of the light M ⁇ ⁇ hc computational channels.
  • light is each v-ompytaUoa channel is atfected by modulators 812.
  • s pmhols aperture 825 is inserted at tlw tl ⁇ a! ⁇ ou*t of converging k ⁇ ?s S25.
  • Th ⁇ s ma> be useful for rejecting scattered light end/Or hici casing the spatial oohejvnco of oc ⁇ apuuit ⁇ nial output bean? 31 OC.
  • the fan in/ fan out system d»jpwted in figure 8 leads itself to the use of «> ⁇ u> atsd two dimensional light modul ⁇ tkm mmys as attenuators 812.
  • Tra sJjuJti ⁇ ag or rcUcctmg att ⁇ j ⁇ maU ⁇ rs may be a>icd xvithin the general scope of ⁇ e current invention.
  • Ii should be- aoted that jntorfcromslers a ⁇ d feedback loops of any of (he types awclosed in the preceding Ogursi. may be used for the optical VVM.
  • Ftgur ⁇ ⁇ J sehcmatscaliy depicts m npticai VMM haviag a coherent feedback loop ⁇ ?0U according to m exempkry emlwdiii-ient of the current invention.
  • Optical VMM 4 X)O compr ⁇ ucx a vjohenjnt light source 304 Light from coherent hgk 5OtJJVCS 304 is piojactcd by a hort ⁇ onlal fan out optics (not shown for clarity) onto a ⁇ ector KttoHuatioii array c ) 10 havmg k individually controllable attenuators 9lO( 1 ⁇ to 910(k) , snd to ft feedback vyrdeal fan out Of ties % X 4.
  • F ⁇ ⁇ b aitemjaior 910 ⁇ o) mo ⁇ luiat «s the light passing through it to rcpre ⁇ mt a xaku v(c) of s vector ⁇ kmeat “c” of vector "v” having dimensioualtty k, to be multiplied wttb a matnx m.
  • r,c) in the 2-L> army 920 modulate the light pawing through it ⁇ Q represent a value m(r.c) of a matrix element to multiplied with the vector. Consequently, tho amplitude oHight at ⁇ in output of attenuator 920(r,o ⁇ is proportional to ⁇ (c)*-m(>v).
  • Each attenuator 9_.0foe is associated with hnriyonial fan in optics (not shows for clarity ⁇ which Jiroct hght from all afees-oators i» row V to the coherent detection dement ⁇ ) ⁇ l ⁇ ) m arr&x C >1 ! otn eieme «ts.
  • the aa ⁇ iitude of light at the input to coherest dtfteciion t ⁇ kaicnt ⁇ 1 l(r) is equal to Sie vector element V ⁇ r) wherein V is a ⁇ ccajr ox ' dm ⁇ onsionahiy ⁇ . ⁇ ?ieate4 b> t ⁇ ui ⁇ ply ⁇ g x ector x- "with matrix m,
  • Light ltom feedback vertical fan out optics 91)4 is pn>jeetcd ot&a & veitkal feedback sfecnuatjos army ⁇ O having B individually controllable feedback attenuatoa 950(1) to °50(u).
  • light f ⁇ >m feedback artcnusCor **50(ri is directed to cofeensxt detection eleme t 91 i ⁇ r) where it isterfcres with light arfivmg &on plurality of atteauator Q 20(r,c) in rov. V.
  • fcaiL'h cohcf est dofectiOR elemcat 911 (r) is associated -VvItIi ⁇ edbaok loop 930 ⁇ t ⁇ f only two f Q 30(l> and Q 30 ⁇ 2) arc shows f ⁇ x clarity), whioh controls the e ⁇ i ⁇ es ⁇ o? ⁇ kng ibodhsok aU ⁇ auator 95« %x) em ⁇ produces the de ⁇ red digital ouljmt ⁇ jsult * ⁇ >! 5 ⁇ r>.
  • Ix should be noted IbM inkjferoiRcter topologies and feedback nj ⁇ thods depicted xn the pjec ⁇ dmg figures may be «&cd for coherent detection element 91 i and fesdbsdc loop O 30.
  • each feedback atictiuator 95 ⁇ f r) may be associated with a weak sii-aiteuuausd beam to enable eobereni det ⁇ tinn topology of fiprtj 5a.
  • ts>mmetrie beam spii ⁇ er ⁇ vithin each dotecuos olemmt V'l l(r) enables fee use of coherent detection topology ol figure 5c.
  • ⁇ coherent source 750 provide* -coheroat light ⁇ o an intf rferometor 7o Q .
  • fcsomctcr ?o9 ⁇ hght froai coherent SOII ⁇ CC 750 is divided between aft upper sieasoreme ⁇ t eh ⁇ and raid a IOWU ⁇ ilvtftack ehaxtnei by a beam splitter 757.
  • transducer 752 may be Cached to the external syster ⁇ or may musg ⁇ d pail of the* externa! system * oj optica! properties of external system tasy be used.
  • transducer 752 may be Cached to the external syster ⁇ or may musg ⁇ d pail of the* externa! system * oj optica! properties of external system tasy be used.
  • Fox example temperature dependence the absorption of an optical ⁇ bei may be used ks modulate the light by changing the iraB&parcney of said fiber.
  • changes m iisikdion, abssorpUo ⁇ pola ⁇ uatioti etc. maybe used.
  • both phase and arsipiimde ⁇ f the light m the mea&ujfemeni chan&d. may be. ai ⁇ eet ⁇ d by the state of the externa! sysiem, however, m ftguies IO nnfy amplitude changes sue con ⁇ ktered, while m figure 11. both phase and amplitade are ticked sn ⁇ opiion ⁇ h' measured Dy the feedback bop.
  • any method of coherent lee ⁇ baek loop (sig ⁇ eJ or imsigaedj ⁇ m ⁇ specifically those depicted in tho ⁇ teccdmg ilguscs may be used.
  • ⁇ sidg, bita ⁇ iy audftr digital feedback ⁇ oops may be used.
  • a signal yen somehown- 761 generates signal st n frequency considerably htgher tha ⁇ the desired sampling ''Me nf system 7 60
  • Signal frosn a NSgBuI geraaator 7 ⁇ j 1 is added to the feedback ioop at a s ⁇ mrmng jimcuoa "71 oM the resulting ⁇ igaal is fed io an ktUnmator 753 through a driver 754.
  • ConscqueaiK. light mtesmtv in the feedback loop performs high, frequency dither around its mean value.
  • a tmad amplifier such si a lock «s amplifier ?5& optionally syschrom/cd to signal generator " ⁇ 1, receives detected Sigcals i ⁇ or ⁇ a detector 755 and extents a sigaed error signal proporaoa&i to tlic HBbalatice ot un ⁇ sfenm ⁇ etoy 769.
  • Op ⁇ otsally a filer, for exaiiipk a low-pass-filte? or a notch filter or both are ⁇ ed for c.t ⁇ 3i ⁇ atioxi ol fee high frequency nxxiuiauoB , before feedback sipui sampling cr a* digital post pri>ces5>ing after it.
  • Figure ⁇ ⁇ dupiet* a sehcm&uc block diagram ofn mcassure ⁇ ieii system $60 u ⁇ ng C ⁇ N hercnt feedback ⁇ ad. capable of measurisig botb ⁇ tt «a «ation and phase shift aeeordmg to an exemplary ombcdtr ⁇ ei ⁇ t of the cmxent invention.
  • UnitUentiotsal relative phase changes T «ay also be eased by changes in the meaiuremcat or the feedback cham ⁇ ei for example due io iueehatucai stress or thssui ⁇ l e ⁇ aasion.
  • phase mc ⁇ iulstor 953 is ⁇ jscrtcc1 mi ⁇ the feedback e-Kur ⁇ ei, In ⁇ x ⁇ exemplary «mb ⁇ di ⁇ i ⁇ t of llg ⁇ re 1 Iu h & ⁇ .
  • IB eostraki to o&er coh « ⁇ jut detection methods used iw the an such aj» the amplitude hcs ⁇ sitsve heterodyne detcetio ' n, commonly used to measure small sigxmK the method according to sotno eaibodsments of the c « ⁇ r?m iBveatios JS sensitive to both pktse and amplitude.
  • Dixeci mcasurcxjjciu of tins light may Iv use « pn ⁇ set ⁇ slue. Co be used as ⁇ al result, Opiio ⁇ aily. with one branch closed and Uis other braach open to a linowti vsiuo, the output light ⁇ n the interfcromctsjr output is proportional to the output of the coherent %lu source.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Nonlinear Science (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
  • Instruments For Measurement Of Length By Optical Means (AREA)

Abstract

La présente invention concerne un système de mesure optique sensible à l'amplitude du champ lumineux. Le système utilise un interféromètre tandis qu'une boucle de rétroaction maintient, à un bas niveau, l'intensité lumineuse sortant d'au moins une sortie optique de l'interféromètre. Le bruit de grenaille d'un détecteur placé à la sortie de l'interféromètre est ainsi réduit, permettant une mesure à grande vitesse et de précision élevée sans nécessiter de source lumineuse plus forte. Le système de mesure peut être utilisé dans le calcul optique.
PCT/IB2006/004287 2005-12-08 2006-12-08 Système optique avec rétroaction cohérente WO2007141598A2 (fr)

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WO2011010314A2 (fr) 2009-07-24 2011-01-27 Technion- Research And Development Foundation Ltd. Convertisseur analogique-numérique (can) photonique ultra-rapide reposant sur l'interférométrie multiphase

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KR101876944B1 (ko) * 2010-12-22 2018-08-09 시리얼 테크놀로지즈 에스.에이. 관찰자 트래킹을 위한 조합된 광변조 장치
AU2017296073B2 (en) * 2016-07-15 2019-02-14 Light Field Lab, Inc. Energy propagation and transverse Anderson localization with two-dimensional, light field and holographic relays

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US5970201A (en) * 1997-09-18 1999-10-19 Lucent Technologies Inc. Power regulation in optical networks
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US5970201A (en) * 1997-09-18 1999-10-19 Lucent Technologies Inc. Power regulation in optical networks
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WO2011010314A2 (fr) 2009-07-24 2011-01-27 Technion- Research And Development Foundation Ltd. Convertisseur analogique-numérique (can) photonique ultra-rapide reposant sur l'interférométrie multiphase

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