11.45 CFI4

An lntegrated Optic Appl"oach to lOllm LlDAR

R M Jenk.lllS. R W J De\ereux and A F Blol,kle\ Laser� and Photoltlcs Department. Defence E\ aluaHall and Research .I\genc)

Room PAW!!. St Andrews Road. Mahan. Worceslershlre En!;land. U.K V\lRH :';PS PhOlle 44 1684 89508+/�95{)oR'. Fa.\ 4� J6l\4 8!J4-166

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The paper describes a novel integrated optics approach to coherent IO.6p.m LTDAR sysLeJIl!S The COIlrepI IS based on usmg hoUow wavc:guides to gUide light bcrnCl:n romponell.� l(X;ated in a conmlOli dl.\::lcctnc substra1e The concept referred to as EQllow �3veguidc Integrated Qptm (HOW-IO), lias am'aJltagcs in relation to achieving and maintaining good coherent mi...ang efficieJldes and has lhe potenl1al to: redUtt size. increase ruggedness and ]ov.-cr manufactunng costs The figure shmvs a plan V!e\\.' photograph of a HOW-TO interferometer subs,'Slcm �hich \'\f ha\'f realtsed m practice. The mtegratcd oomponents and interconnecting waveguides are c1earl)' visible TIlt' subsystem was formed i n 11 lROxJ90xZ(Jmm polycl'vstalJine al umIna SubSlralC usillg a computer confrolled lmU;lIg machine Polycrystalhnt: alumina was chus�:ll as the substrate and lid material because its o p tical pT!1penies. In c�nJunC:l1!1n with \\'hegl.lldcs of approprIate cross sectIon allD\\ Ille realisatIOn of 101\

anenuationcoefficientsat IO(,jJ.m

In pra ctice tht subs;.stc:rn ,-,as based on 20 tuIll WIde w31cgllldes The ass(lciared alignmem slots took components which were 20 0 mIll square and" 0 mm thick Although the 1<IT�e W3yeguide crm,s seclwll IS Ide<ll fOT carr)ing the hiE1l power transmitter heams (.."Omrnonl) reqmrcd In laser radar �stems. 11 also leads to the waveguIdes bemg Inhc:renl1� multImmk. As a consequence misalignment al the poims where olle wa,eguid<: CDupk.s to anolhe:r via an integrated transmissl\'e or rene�l1ve componellt call cause hJghcr order mode excilail()n at the e�pense of fundamental mode coupllng. ThiS process scriousl) impairs �S1em perfonnance In this context. where A. IS the wa\'elellglh of Ihe propagating radiatIOn and a IS the guide half W!dth. field overlap integral calculauons mdicated that angular and laLeral aligruncnt tolcranc<:s of ± Ai} Oa and ± a lO, respectivel)', sll(luld prOVide fundamental mode power coupling effiCIenCies of - 95'% These results wefe u.<;ed as the basis for the machimng tolerances utihzed in tbe manufaclme of the subsystem.

The pafCr pfOVldes detail5 of' (i) the wulerlYlllg theoretical work. (it) fhe manufacture of the sub�stem and. (UI) Its optical assessment The latter mcluded measurement" oftransmiued po�er le\'els and beam profiles. The mset to the figllre illustrates proftJes ar apertures "B" ;md "'C"' [(JUOIlUlg UljeCtiOll al apcnurc 'X' The) indicate that good fundamental mode fidelity is achi:!Ved ill pmru(C Further to this. accurate a..'<sessments of the coherent mixing efficiency generated a ValUE III c.,\.cess of 80% of the meorettcal maXlmlIDl Tn oonjuncuon \l1lh a laser source. some trarumiVroceive optics and a detector, the ,ubs;.ste11l was demonstrated til opcratloll as " SImple \ibrometer The ultiJna.t(: goal of the work IS to re:llll..c full.' mtegrated HOW�IO S}stelllS in .. \inch all required acth-e and pasSI"C oomponcru..s areintegmled UlIO tile same die lectric Stbstrate The onl� extemal oomponell! would be the large aperture se.::on� optic of the transtnltJreeel\e te!eSMpe If successful tilC approacll should lead to a ne». generation of 10.6 iJlIl la'ieT radar systellls The underlying conceptlihould also be applIcable at other wavelengths and to other fonns of (lptlCalsystcm

12.00 CFI5

Studies on laser rangf-gated imaging.

ave Steinvall. Goran Bolander Depl.ufL3scrSy<;lems DI",s.lnn of"en.�urTe.::hn{llogy

Defence Re�t'ardl Es(abJi�ltrnenl (fOAl P.O. Box 1165, S-5fll II LII1l..6pinf' SWEDE!\" Tel +46 D 31::)26,1: Fa:>. +46 n lHHJ66 E'Mail Qveste@'imfoa.se.gorooi@'lin foa .. e

��t:-:::'i�g refer� 10 lhE principle of l ime l::lmtrollmg II camera with respect til a �ubcd illuminating SOUTce Thi .. tcchl1lque was sludied for night photography in reconnai�'ian�e applicatlOn, before the­thermal IR tcchmques \\ere wiael) adopted. In the early days pulsed xenon lamps '''cre used and Ihey wert' Ihen repla�d by lasers. Tociay there st:!em to be a �ome""ha( renewed mrert�51 [or gmOO Ht""-Wg holh lor under\\ aler and atmoopheTic applications. Thl ... i" due to the de\.'�lllplllcnt on Doth lht:! laser and the �amera side. Poy.erful diode plIlllred la�ef"S and calilera tube� with higher spat1nl i:lTId time resolution \\')11 make thl� tedlJliquc and intere�tmg complement to pIDoSIVC EO-imaging AnlOng tile pote nllo! .ml·'H1!<lgC� for laser galed viewm;§' we ran not.:: . Br:!ter angular re�oluuon for tile same dperlurc Sl2e when Ltlmparcd \I·jth tlle;'Tlallnfrared. TIm glvcs

an interesting c('Implemen( for cla",ification (lftargeb u�te.;trd Dr the IR·�ystcm or a raddr Opllcal hack ground suppressIOn due to a short range gale Suppre��l\}n 01 l lllcrfermg l<i .. �r reflections from 1he lEn-am Range tll targC'l <cnn he ohLdlnt'lllogcthcr v,'Ilh imaging infonnation. ImpTO"\ed largel ueteehOIl b) silhollett�det,;:ctjoll. . CaJl3hliity \0 �tt through limoko: aDd other obscurant� and Improved "".",ather penelratmn eompared to short ",avdt:'n�lh pa;"IYC l:.O,s)'slem� OT VISual ,ystem�

ntUer JetC"etlol1 capahilit)' wh�n looklllg inl{) vegetatlUn, building-> Wid cars for a.tmp!c than \':o[]"\cntlonal TV orvl�I,li\1 "\)SCrvatlon

E<;:lIer<-apablllty \0 locate pmnt renCClOfS sucll as land marks In tne form of eorner reflector -or reflex tapes etc

e.

BI Cemredon net+ frOn! of the car ba;:kground, target in em behind nell silhQuen.e

FI;;�re 1. Prmcipie and o.amp/f' oj8(.11ed 1'1�""in8 re.� .. !lr� (FOA Dept. ofl�.l . .rer SPIt'ms).

BeSoldc mlhl<J.ry i1pph�a\J01l5' cj"jlmn appiJeations of galt!d viewing for sean:h alld rescueio and vehicle

enhanc:ed Ylsion" and other arpllcatlOn aTe III progress. This talk investigates the performance for gated VltWlIlg: systern� during dllTcrent alml}�ph�l'ic conditions induding ObSClITa

.nb ..

Example� of gated Images wi!! Ix: g:1"'cn as well a, a di,C"l!ssion 011 galed sy"kms in dJfferertt appllcalmns.

, See for e;;<lmple pro)�ct ERASER and JOA.N"NAH III Joint Warflghting Skn�t' and Technology Plan, US Dept. of Dcfcn�e Plan. Ma} 1996 'D,;-nJs Bonnier ."Rangc-gated active-Imaging s)'siern for �earch·and·rc�cue and sur'l.cillanct: DperaLion�··. pp I :q·j45,SPIE .01 2744, Orlando Apnl 1996 '" P. P("n(lko.",.�kl. "A low COS! vehicle·muunted enhanced "islon �)stem comp�ise? of a laser

illummater and a ran!"'c-gatedcamcra", pp. 222·227. SPIE vol. 27:·6, Orlando Apnl19Y6 Friday / 389