CA2116668A1 - Apparatus for positioning the center of an optical fiber along a predetermined reference axis - Google Patents

Abstract

A positioning apparatus (201, 202, 203) for positioning a point on a cylindrical member having a small diameter such as an optical fiber (F) along a predetermined reference axis (R) regardless of the outer diameter of the fiber.

Description

0~02/~4 lS:33 1er70330532;~0 ~ls~ru~ r Ul'~ Wlr~ lUll ~l~R~; U rl~t~ rlU U J ~r PCTJUS 92/0~88 .

TITL~3:

10 ~
,..~

Thi8 applic~tion i~ a con~nuation~ part of appl~cation Ss~ xr 07/631,26a, filcd I)ecember ~0, 1990 (ED-377-B), ~h~ch i~ itself a file wrapper continuation o~ applica~on Se~ial Number 071388,546, ~iled August ~!~ 1989 (ED-3T7) (nolw ~.
aband~ned~. /

Subjcct matter di~closcd herein i~ clo~ed a~d c~aimed in copending appL;cation Serial Number 07/838,638, filed August 30, 1991, tL'dcd "An Optical P`ibcr Con~ector Havi~g An Apparabls For Po8itio~g The Center Of An Op~ical Fiber Along A P~determincd Refa~nce Axis" q3D-377-D), th~t ~pplica~on 2~ bemg a ¢onffnuation~ part of ~oper~ pplication Serial Number 07t~i2~,001, filcd December 17,l9gO (II;D-377~A), whic~ is itself a ~ion of applica~ion 8eri~ Numbe~ 07/388,546, fi~ed Au~st 2, 1989 (ED-377) (now aba~don~).

au~ect m~ter disclo3ed he~em i~ also di~ ed and ~laimed i~ cope~ding applica'don &~i~l Number 07175~,283, filod contes~n~oraneou~ly hetewi~ titlcd "Opto-Electronic Component Ha~ing Positioned Op~ical ~iber A~sociated Th~:rewi~" (I~:D-378-A), that application bein~ a contis~ation-in-3~ part of copend~ appic~ n Serial Number 07/38~,548~ filed August 2, 1 g8~ (ED-~7a).

- SUBST~TUl E SHEET
IPEA~

wo 93/05415 , Pcr/uss2/073ss ;

BACKGROUND OFT~ I~VI~ION

Ficld Of The Invcntion The present invention relatcs to 5 a posidoning apparatus for positioning the ccntcr~of an`optical fiber or other small dimensioned cylindrical member, such as capillary tubing, along a- prcdetcrmincd rcfcrcncc axis independently of variadons in thc outside diameter of the membcr.
i cs~ri~tion Of The P~ior Art Devices arc Icnown for posidoning an opdcal fibcr so that the axis of thc fiber is positioncd with rcspect to a rcfcrcncc axis. A typical cxpedicnt uscd in such deviccs is a gencrally V-shapcd groovc that is 15 fonned in a substrate material and which scrves as a cradlc to accept thc ~lber being posidoned. Representativc of such dovices is that shown in United States Patent 4.756,591 (F~scher ct al.), whcrcin a V-groovc is f~med in a silicon substrato and an clastomcric mcmber is biasod against the 20 fiber to boW it in thc groovc. Thc groovc may be stcpped to providc a dceper groovc scgmcnt to hold thc jaclcet of thc fiber within thc dcvicc.

Unitcd States Patcnt 4,756,591 (Shccm) discloscs a 25 groo~ed silicon substratc having a pair of intcrsecting V-groovcs thercin. A fibcr to be positioned is disposcd in one of the groovcs while a shim is disposed in the othcr of the groovcs. Tbe shim may take~ thc f~rm of a tapered or an Icccentric fibcr, which wben respcctivcly slid or rotatcd undcr 30 thc first fibcr serves to lift the same to bring thc a~cis thercof into alignmcnt with a refercnce axis. A cover may be positioncd abovc thc substratc to assist in clamping the first fiber into positio-.

wo 93/0s4ts Pcr/uss2/0738s United States Patent 4,~02,727 (Stanley) also discloses a posidoning arrangement for optical components and waveguides wbich utilizes a V-grooved structure. United States Patent 4,826,272 (PimpineUa et al.) and United States 5 Patent 4,830,450 (Connell et al.) discloses arrangem-ents for positioning an optical fiber that utilize members baving frustoconical apertures therethrough.

It is belieYed that single crystalline silicon is the material 10 of ehoice of the devices above mendoned because of tbe proclivity of crystalline silicon to be etched along precise crgstallographic planes, thus forming precise grooves or structural features by photolithographic microfab~ication teehniques. Etehants exist tbat act upon a selected 15 erystdlograpbic plane to a differendal degree than upon an adjaeent plane, pennitdng tbe needed preeise eontrol. V-grooves, in partieular, ean be etehed to a eontrolled width and truneated deptb. Under some eonditions V-grooves may be etebed in a self-limidng operation. The photolithograpbic 20 microfabricadon proeess is generally deseribed by 8rodie and Muray, "Tbe Physies of Microfabrieadonn, Plenum Publishing, New York (1982).

Optieal fibers inelude an inner eore having a 25 predetermincd index of refraedon surrounded by a cladding layer of a lower index. The inner eore is tbe medium in which the optieal energy is guided, while tbe eladding layer defines tbe index bounda~y with tbe core. Tbe outer diameter of tbe fiber may vary in dimension about a predetermined nominal 30 dimension. It has been seen, for example, tbat two nomina!ly identieal fibers from tbe same manufacturer may ~rary in outside diametriea1 dimension by as much as plus or minus four (4) n~icrometers. Tbis fiber to fiber ~rariadon in outer diameter makes diffieult tbe accurate positioning of the axis of 35 the eore of a fiber with respect to a predetermined reference wo 93/05415 Pcr/uss2/0738s 2116~68 axis using a positioning apparatus having a V-grooved structure.

In view of the foregoing it is believed advantageous to 5 mal~e usc of tbe ability of microfabdcadon tech~i~es to form accurate structurcs, channcls and/or surfaccs in a crystalline matcrial to construct a posidoning apparatus that will accurately position thc ccntcr of the ffber, or of any other clongatcd generally cylindrical membcr having small IO dimcnsions (such as capillary tubing), with respect to a predetcrmined refcrcncc axis. Moreover, it is bclieved advantageous to provide a positioning apparatus that consistcntly aligns the predctermined point on the ffber or other cylindrical mcmber with the refcrcncc axis without 15 requiring great technical sldll, cxpcnsive apparatus, and cxtcnsivc alignment procedures.

, "

.

wo 93/05415 Pcrluss2/07388 ~UMMARY OF THE lNVENTlON

The prcscnt invention rclatcs to a positioning apparatus for positioning a pr~dctcrmined point, such as the geometric 5 ccntcr, on thc end facc of a cylindrical member,,such as`an optical fiber, along a predetermined reference axis. In a preferred casc the posidoning apparatus includes a first and a sccond arm, cach of which has at least a first and a sccond sidcwall that coopcrate to dcfine a groove thercin. The groove 10 in cach arm is prefcrably a convcrging groovc so that when the arms arc arranged in supcrimposed tclationship the converging groovcs cooperate to define a funnel-like channel over at Icast a predctermincd portion of its Icngth. The channel has an inlet cnd and an outlet end and a rcferencc axis extcnding 15 thercthrough. A fibcr inlroduced into the inlet end of the channel with its axis spaced from the reference axis is displaceable by contact with at least onc of thc sidcwalls on one of tbe a~ns to place a predetermined point on an end face - of the member into alignment with thc rcferencc axis where it is therc bcld by contact with tbe first and second arms. To guide the fiber toward the inlet end of the channel each of the first and the second arms includes a trough therein, each trough bcing disposed on an arm a predetermined distance bchind the groove in that arm, so that in the closed position the troughs cooperate to define a guideway.

The arms having the converging grooves therein may, as is prefetred, be movable from a first, closed, position to a second, centering, position. The superimposed arms are, in this 30 instance, mounted cantilevered fashion, to a foundation. Means is provided for biasing each of the arms with a substantially equal and oppositely directed biasing force toward the first position. ln the preferred implementation the biasing means comprises a rcduccd thickness portion in each of the first and the second arms, the teduced thickness ponion defining a Wo 93/0~41s Pcr/us92/o73ls 2ll666~
- flexure in each arm which, when each arm is deaected by contact with the cylindrical membcr, gcncrates a force on each arm to bias each arm toward the closcd position.

It should be understood that so long as the,~ins are-`
movable and biased toward the closcd posidon, it is not required that tbe grooves formed thcrcin are con~rerging grooves. Accordingly, other positioning apparatus in which the arms are movable but in which the grooves in each of the arms have a form other than a converging groove are to be construed as Iying within the contemplation of the invention.
Succinctly statcd, the prescnt invcntion cncompasses any positioning apparatus having arms that are movable whether the groove in cach arm take the form of a converging groove or a groove of an alternate form. Alternately, the present invention also encompasscs any positioning apparatus in which the groovc in each arm is converging in form, whethcr the arms are movable or fixed with respect to each other.

In another aspect, the prcsent invention relates to a fiber-to-fiber connector formed from con&onting pairs of positioning apparatus. Such a connector is, in the preferred instance, disposed in a housing.

2~ In whatevcr embodiment realizcd, it is preferred that the positioning apparatus be fabricated from a crystalline material, such as single crystal silicon, using microfabrication techniques.
Each structural element of th~e positioning apparatus (viz., each of the arms and each foundation) is fabricated in mass on a wafer of silicon. The finished wafers are aligned, wo 93/OS415 Pcr/usg2/073s8 superimposed, and bonded, and each of the rcsulting positioning apparatus se~ercd from tbe finished asscmbly of bonded wafcrs. Alignment betwcen superimposed wafers is assurcd using sclected ones of a plurality of alignment grooves 5 on each of the wafers and associatcd prccise di~mcter fibers.

,~

wo 93/05415 rcr/uss2~073ss 2~ C18i In a most prcferred embod~ment each of the two arms are divided into two arm scgments, or fingers, to compensate for slight misalignments of the grooves.
.

! .

~: ' ',''~ , -WO g3/0541~ PCr~USg2/07388 9 21I6ii68 BRI~ DESCRIPTION OF T~ DRAW~GS

Tbe invention will be more fully understo~ from~ the following detailed descripdon thercof, talccn in conncction with the accompanying drawings, which form a part of this application, and in which:

Figure 1 is a pcrspecdve, cxplodcd ~riew of a positioning apparatus in accordance with one embodiment of the present invention for positioning the center point on the end face of an optical fiber with rcspect to a predetermined refcrence axis;

lS Figure lA is a definitional drawing illustrating the characteristics of a convcrging groove as that tenn is used in this application; -Figure 2 is a perspective vicw of thc positioning 20 apparatus of Figurc I in thc fully assembled condition;

Figure 3 is a front elcvation Yiew of the assembled positioning apparatus of ~igures 1 and 2, talcen along view lines ~ 3-3 in Figure 2;
2~
Figure 4 is a sccdonal view, in elevation, of the assembled positioning apparatus of Figure 2, taken along section lincs 4-4 in that Figure illus~adng the truncated V-groove therein;

Figure 4A is a view generally similar to Figure 4 in which a full V-groove is formed in the positioning apparatus while Figure 4B is a view generally similar to Pigure 4 in which both a full V-groove and a truncated V-groove are formed;
,.~; - , .

WO g3/05415 PCI/US92/07388 .6~6~ 1 o - Pigure S is a plan vicw one of the arms of the positioning apparatus of Figurc 1 illustrating thc rclationships of the axes of thc groovc and thc guidcway thercin;

Figurcs 6A an~d 6B, 7A and 7B, and 8A and 8B are diagra~ tic c!cvàtional and cnd ~ricws of thc acdon of thc clips disposcd on the arms of thc posidoning apparatus shown in Figurcs 1 and 2 in rcsponsc to the introducdon of a ffbcr thercinto;
Pigurcs 9 and 10 are cxplodcd and asscmblod perspective views, gcncrally similar to Figurcs 1 and 2, of another altcrnate cmbodiment of a posidoning device in accordance with the present invendon in which the arms have nonconvcrging groovcs therein and in wbich thc arms are articulably movable with rcspcct to each other along onc axis only;

Figures 11 are 12 are secdonal views taken along section lines 11-11 and 12-12 in Figure 10;
Figures 13 and 14 are exploded and asscmbled pcrspccdve vicws, generally similar to Figures 1 and 2, of anothcr altcrnate cmbodimcnt of a positioning dcvice in accordance with the prcsent invcntion in which only one of tbe 25 - anns has a nonconvcrging groove thercin and in which both of thc arms are articulably movable with respect to cach other;

Figures 15 are 16 are sectional views takcn along section lines 15-15 and 16-16 in Figure 14;
Figures 17 and 18 are exploded and assemblcd perspecdve views, generally similar to Pigures 1 and 2, of an alternate embodiment of a positioning device in accordance with the present invendon in which the arms have converging WO 93/05415 PCI~/US92/07388 11 21166~8 grooves therdn and in which tbe arms are f,ixed in position with respect to each other;

Figure 19 is an end view taken along view lines 19-19 in 5 Figure 18;
.. ..
Figure 20 is a side sectional view, talcen along view lines 20-20 in Figure 18, illustradng the position of the fiber within the channel of the a positioning apparatus in accordance with ', lO the alternate embodiment of the invention shown therein;

Figure 21 is an exploded isometric view of a pair of positioning apparatus as shown in Figure 1 used to form a fiber-to-fiber connector in accordance with the present 15 invention wbile Figure 22 is an isometric view of the fully assembled conneetor of Figure 21;

Pigures 23 and 24 are, respectively, a top view in section and a side elevation section view of a pair of posidoning 20 appa~us in accordance the embodiment of the invendon as shovm in Pigure 17 used to fonn a fiber-to-fiber connector in accordance with tbe present invention;

Figures 25 and 26 are isometric views of a housing used 2~ for,the fiber-to-fiber connector shown in Pigures 21 and 22 in the opetl and in the partially.closed posidons, respectively, while Figure 27 is a section view of the. bousing of Pigure 25 in the fully closed position taken along section.lines 27-27 of Figure. 26;
., 30 Figure 28 is a secdon view generally similar to Figure 27 of a housing used for the fiber-to-fiber connector shown in ,:~Pigure 24;

wo 93/05415 rcr/uss2/073ss ~ 2~666~ 12 ` ' Figurc 29 is a isomctric vicw of an alternate housing for a fiber-to-fiber connector formed of a pair of posidoning apparatus;

Figurcs 30 and 31 are isomctric cxploded and assemblcd views, respecdvely, illustrating tbe usc of a pos~doning apparatus in accordance with the prcscnt invcntion to position an opdcal ~Iber with rcspect to the axis of an edge cmitdng active dcvice, in which thc dcvice is surface mountcd;
Figure 31A is a side dcvational vicw generally similar to Figure 31 showing a positioning apparatus in accordance with the prescnt invention positioning a lens with respect to an opto-clcctronic component;
Figurcs 32 and 33 are isometric cxplodcd and assembled vicws, rcspcctivcly, gcncrally similar to Figurcs 30 and 31, illustrating thc usc of a positioning apparatus in in accordance with thc prcscnt in-rcn~ion to posidon an optical fibcr with rcspect to thc axis of a device having active surface dcvice, in which the dcvicc is mounted to the cnd of a positioning apparatus;

Figurcs 34A througb 34F are cnd vicws showing altcrnatc a¢rangcmcnts of movable arms cach holding a cylindrical mcmber along at Icast three contact points in accordance with the prescnt invcntion;

Figure 35 is a perspective view of a positioning apparatus ; 30 havirtg a set of four articulably movable arms in accordance with an alternate cmbodiment of the present invcntion for posidoning thc ccnter point on the cnd face of an optical fiber with respect to a predetermined reference axis, the mounting foundation being ommitted;

wo 93/05415 PCr/USg2/07388 13 2116G~8 Figures 36A and 36B are an isolated perspecti-ve views of two of the fingers of the positioning apparatus of Figure 3S;

Figure 37 is a side ele~radon ~iew of the assembled posidoning apparatus of Figure 35;

Figures 38 and 39 are seedonal views of tbe assembled posidoning apparatus of Fi~ure 37, respeedvely talcen along seetion lines 38-38 and 39-39 in Figure 37;
Figure 40 is a top view of the positioning apparatus of Figure 37 taken along view lines 40-40 therein;

Figure 41 is a side elevadonal view and Figure 42 is a front elevadonal ~tiew of the assembled posidoning apparatus with the fingers holting a fiber in tbe centering position, the : moundng foundation of the posidoning apparatus being ommitted;

Figure 43 is a: front elevadonal ~iew, similar to Figure 42 illustradng the situadon extant when the finger pairs are - misaligned, while Pigure 44 is a view illustrating the misaligned finger pairs bolding a finger in the centering position; and Pigure 45 is a perspective ~riew of an enhaneed positioning apparatus that ineludes the posidoning apparatus of Figure 35 and further ineludes a elamp rearwardly disposed therefrom, the moundng foundation of the posidoning apparatus being ommitted;

Pigure 46 is a perspective view of a wafer used used to fabrieate a plurality of anns or foundadons used in a posidoning apparatus in accordance with the present invention;

WO 93/OS415 Pcr/uss2/o7388 Figure 47 is a perspective view of a mask used in the photolitbographic proccss fo~ning a plurality of arms or foundations for a positioning apparatus in accordance with the present invention~
. ~
Figure 48 is an cnlarged view of a portion of the mask used for creadng a plurality of arms on the wafer 34;

Figures 49A through 49E are schematic representations of the process stcps effected during fabrication of the wafer;

Pigure 50 is is an cnlarged view of a portion of the mask used for creating solder masks on the wafer;

Figure 51 is an enlargcd vicw of a portion of the mask used for creating foundations on the wafcr;

Figures 52A through 52D are schematic representations of the steps used to form a plurality of fiber-to-ffber conncctors from supcrimposed wafers having the arms and foundations thercon.

WO 93/05415 PCI`/US92/07388 21i6668 Throughout the following detailcd dcscription similar 5 refcrcncc numcrals rcfcr to similar clcmcnts in all~igures--of tbe drawings.

For purposes of a gcncral ovcrvicw Figurcs I and 2 show a posidoning apparatus gcncrally by rcfcrcncc character 20 in 10 accordancc with onc cmbodimcnt of thc prcscnt invcntion in an cxplodcd and in a fully assemblcd condition. Pigures 9 -through 12 illustrate a positioning apparatus generally indicatcd by refcrcnce character 201 in accordance with anothcr cmbodiment, wbilc Figurcs 13 through 16 and Pigurcs 17 through 20 illustrate still altcrnatc cmbodimcnts 202, 203, respcctivcly, of tbc posidoning apparatus in accordance with the invcntion. Figure 34A through 34C illustrate yct anotber al~crnatc cmbodimcnt of a positioning apparatus 204 (having thrcc ~ns). Figurcs 34D through 45 illUSmltC yet another altcrnate cmbodimcnt of a positioning apparatus 205 in accordancc ~vith tbe in~rcntion in wbich thc uppcr and lowcr arms ha~e bccn subdivided into upper and lower pairs of arm segmcDts, or fingcrs.
.
Although throughout this application the positioning apparatus is cast in tcrms of positioning an optical fibcr, it is to be understood that the prcscnt invcntion may be cffectivcly utilized with any othcr membcr having the fonn of a small diameter cylintrical object. By`way of example and not limitation, the positioning apparatus in acco~dance ~ith the prescnt invcndon may be used to position a point disposed~ for example, on the cnd face of a length of microtubing or capillary tubing. By small diameter it is generally meant less than 0.04 inch (onc (1) miUimeter)?~but usually less than 0.020 inch.
Morcovcr, it should be funbor understood tha~ the term WO 93/05415 PCI`/US92/07388 666a cylindrical is not to be strictly limitcd to an object having a completely circular outcr configuradon, but would apply to any object wbose outcr contour is symmetrical to its ccntral axis.
Tbus, again by~a~y of further examplc and not limitadon, the positioning apparatus of the present invcntion may_~e uscd to position a point disposcd, for example, on tbe end facc of a polygonal sbapcd member or an elliptical membcr.

As will bc devclopcd herein, in thc preferred instance 10 each positioning apparatus in accordancc with tbis invention is microfabricatcd from single crystal silicon or another diffcrcntially ctcbablc single crystalline material. Crystalline materials are prcfcrred bccause tbcy pcrmit the accura~e formation of tbc structural featurcs of the positioning 15 apparatus in accordancc with the prcscnt invention using the process of differcndal ctcbing.

Any of the positioning apparatus hercin discloscd is uscful in accurately placing or accurately positioning a center 20 point on a-fiber, typically a ccntral a~ial point on the cnd face of the fiber, into alignment with a prcdetermined refercnce axis and for maintaining the center point in alignmcnt with the refcrcnce axis. As will be developed this refcrcnce axis itself may be collinearly aligncd with respect to another axis.
By accurately placing or accuratcly posidoning a ccnter point into alignment with a predetermincd rcfcrence axis it is meant that a point, such as a point on the cnd face, of the fibcr is brought to within a predetermined distance of thc rcfcrcnce 30 axis. This distance is, in general, on the order of a fcw micrometers (i. e., less than about five micrometcrs) for multi-mode fibers. ln the case of a single mode optical fiber, a positioning apparatus in accordance with the prcsent invention is cspecially adapted for positioning a point of the fiber, such as 35 a point on its cnd face, to within the prccise distance required .

to couple effectively ligbt from the single mode fiber into another fîber or into an opto-eleetronic device or to eouple effectively light from a source, as a solid state laser, into the fiber. This precise distance is even Iess than for multi-mode 5 fibers for eomparable coupling loss. f~

The positioning apparatus in aecordanee with the invendon is also adapted for positioning a point on the end face of a multi-mode fiber with respeet to a referenee a~cis.
It should understood tbat the fiber need not be held by the positioning apparatus at the end face of the fiber in order to obtain the accurate posidoning of the point on the end face into alignment with the referenee a~cis. ln pracdee, the l 5 positioning apparatus contaets tbe fiber a predetermined elose distanee (on the order of two hundred mierometers) from the end faee. Contacdng the fiber at a Iocadon rearwardly &om its end faee impans the eapability to sbut the end face of a fiber with the end faee of a eonfronting fiber (ss in a eonneetor), or 20 to abut the end faee of a fiber with a eon&ondng surfaee of a deviee (as in sn eleetro-opdeal eomponent).

In some instances an enhsnced positioning apparatus may be prwided in order to permit more aeeurate plaeing or 2S more accurate posidoning of the point on the end faee of the fiber into alignment with respeet to the predetermined a~cis. To this end, a second posidoning apparatus, spaeed rearwardly from the first positioning app~aratus, may be used to funedon as an alignment clamp for the f ber. This arrangement is sccn in 30 Figure 45. Using an enhanced posidoning apparatus, the center point on the end face of the fiber may be accurately positioned into alignment with a predetermined reference axis such that the center point lies within a distance of less than one micrometer of the reference axis.

wo 93/05415 Pcr/usg2/073s~s 2~666~ - 1 8 If not apparen~ from the foregoing, it should also be understood that a posidoning apparatus in aeeordanee with the present invention may be used to aceurately plaee or aeeurately position: any other point on the eenter a~is of the 5 fiber into alignment with the predetermined ax~

-o-O-o-As noted, the eylindrieal member preferably takes the 10 form of an optieal fiber. The posidoning apparatus of the present invendon is pardeularly adapted to plaee a predetermined point P on the end faee E of an optîcal fiber F
along a predetermined reference axis R. ln pracdce the point P
is the geometric eenter and lies on the axis A of the core C (e. g., 15 Figures 6A and 68 and Pigures 41 and 42) of the fiber F. The eore C is itself smrounded by an outer eladding layer L. A
jaelcet J is pro~vided about the eladding layer L but is stripped from the fiber F prior to the insertion of the fiber into the posilioning apparatus 20. The jaelcet may eomprise more than 20 one layer. As discussed pre~iously, the dimension of the outer diameter D of the eladding layer L of the fiber F may ~rary from fiber to fiber. Typieally this diametrical ~anation~ from ~Iber to fiber is on the or~er of tluee (3) micrometers. This situation ma~es diffieult-the posidoning of the point P along the 25- referenee a~cis ;R using the positioning de~riees of the prior art.

-o-O-o-With reference to Figures 1 and 2 it is seen that tbe 30 embodiment of the positioning apparatus 20 there shown includes a first and a second arm 22A, 22B, respectively.
Preferably, each of the arms 22A, 22B is identically fo~ned in a manner to be discussed, so the structural details of only one of *e anns,- e. g., the ann 22A, will be diseussed. It should be 35 appa~ent, however, that each structural detail of the arm 22A

19 2I1666~ -finds a counterpart in the otber arm 22B. Accordingly, corresponding refercnce numerals with tbe appropriate alphabet suffix will denote corresponding structural details on the arm 22B. If the arms are not substantially idendcal (as, for 5 examplc, in the embodimcnts of Figurcs 13 thro,~ 16 and Figure 42) adjustments must be made to providc the requisite biasing forces to maintain the point P on the refcrence axis R

Thc ann 22A includes a basc portion 24A having a first 10 major surface 26A and a second, opposed, major surface 28A.
The base portion 24A cxtends along the full Icngth of the arm 22A and the dimcnsion of the central rcgion 25A of the base portion 24A dcfincs the basic dimension of the arm 22A. A
clip gencrally indicatcd by the refcrence charactcr 30A is 15 defined at a first end of thc ann 22A. Thc clip 30A is formed in a relatively thiclc~r abutment portion 32A that lies on the first surfacc 26A of thc arm 22A. Tbe abutment 32A has a planar surface 34A thereon Iha~ prcferab!y lics parallel to the first major surface 26A. To provide some feeling for the 20 physical dimensions involved, the arm 22A has an overall length dimension on thc order of twcnty eight hundred (2800) micrometers and a width on the order of three hundred ~lfty (350) micrometcrs. In thc central rcgion 25A the ann 22A has a tbiclcncss dimcnsion on the ordcr of fifty (50) micrometers, 25 while tbe remaining portion of the arm 22A bas a thickness dimcnsion on the ordcr of one hundred twenty fi~re (125) micrometers.

As may be better seen with reference to Figures 3 and 4 30 a generally converging V-shaped groove 36A is defined in the abutmcnt 32A of the clip 30A by generally planar first and second sidewalls 38A, 40A, respectively, and the forward end region of the first surface 26A of the base 24A. The sidewall 38A has an upper edge 39A (Figure 1) thereon while the 35 sidewall 40A has an upper edge 41A thereon. It should be wo 93/05415 Pcr/uss2/073ss 666Y~ 20 understood that the tcrm "planar" is mcant to encompass a surfacc formcd in a singlc crystal matcrial by etching in which microscopic steps are of necessity produced owing to the lattice structure of the crystal.
Witb reference now to thc definitional drawing of Figure IA, the meaning of the term "convcrging" wben applied to a groove in any embodiment of thc invention herein disclosed (using the rcfcrence charactcrs of Figures 1 and 2) may bc 10 made more clear. As uscd herein, a "converging" groove is a groovc 36 dcfincd from at least two planar sidewalls 38, 40 and has an enlarged inlet cnd 42 and a narrower outlet end 43.
The respective upper edges 39, 41 of the sidewalls 38, 40 of the groove 36 lie in a reference plane RP having a reference 15 axis R Iying therein. Tbe planar surfaces 34 also lie in the refcrcnce plane RP. The reference axis R extcnds in the refercnce plane RP from the inlet end 42 to the the outlct end 43 of ~c groove 36. Each point on the refercnce axis R is spaced in the reference plane RP an equal perpendicular 20 distance from the respecdve upper cdges 39, 41 of the sidewalls 38, 40. The distance between the upper edges of the sidewalls and the axis R decreases from the inlet end 42 to the outlcl end 43 of the groove 36.

The surfaces of the sidewalls 38, 40 are equally and oppositcly inclincd with respect to the reference plane at an angle A grcatcr than zero and Icss than ninety degrees. The angle of inclinadon A is determined by the latdce structure of the crystal, and in the case of (100) silicon, is 54.74 degrecs.
The projections of the sidcwalls 38, 40 intersect in a line L that itself intersects the reference axis R forwardly past the outlet end 43 of the groove 36. Tlhe line L is inclincd with respect to t}~.e reference plane RP at an angle B that is greater than zero degrees but less than ninety degrees. In the reference plane 35 RP thc upper cdgcs 39, 41 of the sidcwalls 38, 40 cach wo 93/05415 Pcr/uss2/073ss eonverge toward the referenee axis R at an angle C that is on the order of two and one-half to five degrees (2.5 to 5) degrees, and most preferably at about three (3) degrees. The angle B is dependent upon the values of the angles A and C and typically 5 the angle B lies in the range from about fo0 (4),~ve ~5)`
degrees. As used berein a "fully funnel-lilce" ehannel is a ehannel that is defined by the cooperative assoeiation of at least two eonverging grooves. A "partially funnel-lilce" channel is a ehannel that is defined by one eonverging groove and a 1 0 surface.

From the foregoing it may be readily understood that a "uniform width" groove is one in which each point on the referenee axis R is spaced in the reference plane RP a uniform 15 distanee from the edges 39, 41 of the sidewalls 38, 40 as one progresses from the inlet end 42 to the outlet end 43 of the groove 36. The sidewalls of a uniform width groove may be inelined with respeet to referenee plane RP, or they may e~ctend perpendieularly to it, as desired. A channel fonncd from one 20 or two uniform width groove(s) is termed a "uniform width"
ehannel. Sueh a ebannel may have a rectangular eross seetion in a plane perpendieular both to the referenee plane and to the referenee axis, assuming no inelination of the sidewalls of the groove.
- A tapering groove is one in whieh the planar sidewalls are perpendieular to the referenee plane but the distance in the referenee plane between the referenee axis and the edges of the sidewalls deereases as one progresses from the inlet to the 30 outlet of the groove sueh that the extensions of the planar sidewalls intersect in a line that itself interseets perpendicu1arly with the reference axis.

ln the embodiment seen in Figures 3 and 4 the groove 36 35 is a eonverging groove, and more preferably, is a V-groove WO g3/OS415 PCl~/US92/07388 6 Iruncated by the presence of third sidewall defined by a portion of the major surface 26 of the arm 22 in which it is disposcd. The truncated V-groove bas the same depth throughout its lengtb, when measured along a dimension line 5 erected pcrpcndicular to tbc surface 34A of the, ~utment 32A
in a direction extending toward tbe ma~or surfacc 26A~

It should be understood that tbe V-shape of the groove 36A may take alternatc forms and rcmain within the 10 contempladon of the invendon. For example, as seen in Figure 4A, the groove 36A may be defincd by only tbe first and second sidewalls 38A, 40A, respectivcly, in which cvent the groove 36A appears as a full V-shape throughout its length.
Thc apcx 42A of thc groovc 36A thus appcars throughout the 15 full length of the groovc 36A.

Figure 4B shows another alternative arrangement in which a truncatcd V-groovc (dcfincd by thc first and second sidcwalls 38A, 40A, respectivdy, and the portion of ~he major 20 surface 26A) extends for some prcdetermincd axial distance while a &ll V-groove (defined by the first and second sidewalls 38A, 40A, rcspectivcly) extcnds for some sccond predetermined distance. Thus, as scen in Figurc 4B, when measured along a dimension line erccted perpendicular to the 25 surfacc 34A of the abutment 32A in a direction extending toward tbe major surface 26A the dcpth that the groove 36A
extends into the abutmcnt 32A is greater at its inlet end 42 (as indicated by the dimension arrow 44A) than it is at its outiet cnd 43 (as indicated by the dimension arrow 46A).
The fully truncated V-groove shown in Figure 4 is preferred for the embodiment of Figures 1 and 2. For purposes of ease of manufacturability, as will be made clear herein, it is also preferred for the embodiment of Figures l and 2 that the 35 groove 36A does not converge throughout the full axial wo 93/05415 Pcr/usg2/073a8 distance through the abutment 32A. Owing to the provision of tabs 48A, 48B (Pigurcs 1 and S) formed near the ends of the abutments 32A, 32B, the sidewalls 38A, 40A dcfining the groove 36A do not converge throughout the full Icngth of the 5 groove, but dcfine a short uniform width portion ~st past the convcrging portion of thc groove 36A. Tbe ovcrall axial Icngth of thc groove 36 (including both tbc converging and thc uniform width portions) is on the ordcr of three tenths (0.3) of a millimeter, while the uniform width portion of the groove lO occupies an axial length of one tenth (0.1) of a millimctcr. As is believcd bcst seen in Figure S the converging and nonconverging portions of thc groove 36A have a common axis 50A associated ~hcrewith.

Again with reference to Figure 2, an extended enlargement region 54A having a planar surface 56A lics on the basc portion 24A of the arm 22A spaced a predetermined axial distance 58A behind the abutmcnt 32A. Thc distance 58A is on thc order of one (I) millimeter. The surface S6A is 20 coplanar with the surfacc 34A. The enlargement 54A is provided with a nonconvcrging, uniform width, truncated V-shaped trough 60A dcfined by inclincd planar sidewalls 62A, 64A, respecti~dy, and by a portion of the major surface 26A of the base portion 24A ncar the second end thereof. In the 25 cmbodimcnt shown in Figures I and 2 the trough 60A is uniform in depth along its axial length, as measured with respcct to a dimcnsion line erected perpendicular to the surface 56A toward the major surface 26A. The trough 60A
communicates with a convcrging lead-in 68A. If desired, the 30 walls 62A, 64A may be inclined with respect to each otbcr so that tbe trough 60A may be a full V-shape or a partial V-sbape, similar to the situation illustrated in connection with Figures 4A and 4B for the groove 36A. Alternatively, the walls 62A, 64A defining the troughs 60A, 60B may be parallel or 35 otherwise conveniently oriented with respect to each other. As WO 93/0541s Pcr/us92/07388 666Q~ - 24 is bclievcd best seen in Figure S the trough 60A and the lead-in 68A havc a common a~us 70A. Thc length of thc trough 60A
and associated lead-in 68A is on tbc ordcr of l.S9 millimetcr.
.
Figurc S is a plan view of onc of thc arms 22A; In thc prcfcrrcd implemcntadon of thc cmbodimcnt of ~Figurcs 1 and 2 thc axcs SOA, 70A (rcspectivcly through the groovc 36A and tbc trough/lead-in 60A/68A) are offset a predetermined distancc 72 in the refcrence plane RP (the plane of Figure S).
Prefcrably, thc offsct 72 is at Icast one-half the diffcrcnce bctwccn the diamctcrs of the andcipated largest and smallest fibcrs to be posidoned. As will become clea~er herein offsctdng the axes SOA, 70A of the structures 36A, 60A/68A
facilitates thc ccntering acdon of the positioning apparatus 20 by insuring that a fiber, as it is introduced into thc apparatus 20, is biased to stril~c one of ~he sidcwalls 38A, 40A forn~ing the groo~re 36A (and analogously, tbe sidewalls 38B, 40B
f~nming tbe groove 36B). Tbis insures wall contact with tbc fiber at at Icast two spaced locadons. Howe~rcr, the prcsence of the offsct 72 ncccssitatcs addidonal manufacturing consideradons, as will bc discussed. It should bc notcd tbat tbe forcc rcsulting from Uasing tbe fibcr in the manner just discussed (or the forcc on ~hc fibcr due to gravity) is much smallcr in magnitude than the biasing force of tbe arms wbich servcs to ccntcr the fibcr on the rcferencc-axis. ~

ln tbc asscmblcd condition the arrns 22A, 22B are disposed in supcrimposcd relationship one above the othcr, with the groovc 36A, the troùgh 60A and the lead-in 68A on the one arm 22A rcgistering with the corresponding groo~e 36B, trough 60B and lead-in 68B on the other arm 22B. The rcgistcrcd con~rerging groo~res 36A, 36B in the abu~ments 32A, 32B cooperate to define a generally fully funnel-shaped channel 92 having an input end 94 (Figure 4) and an output 35 cnd 96 (Figures 4 and S). (Note that if the tabs 48 are wo 93/05415 Pcr/uss2/073ss providcd, the channcl 92 so defined has a uniform width portion just preccding the outlet end 96 thereof.) The rcfcrcncc axis R extcnds ccntrally and axially through the channcl 92. The rcfcrence alcis R lies on thc interscction of the 5 rcfcrcnce planc RP (which contains the conjoined su.rfaccs 34A, 34B) with the phne cont2ining the axes SOA, 50B of the convcrging groovcs 36A, 36B.

The registered troughs 60 and lead-ins 68 cooperate to 10 define a guideway 98 (Figure 2). Similarly, the axis R' through ~he guidcway 98 lies on the intersection of the plane containing the conjoined surfaccs 56A, 56B of the cnlargements 54A, 54B
(which is the refcrcnce plane in the preferred case) with the planc containing the axcs 70A, 70B (Figure 5) of the 15 troughllcad-in 60A/68A, 60B/68B. Thc axcs R and R' both lie in the rcfcrence planc RP (the plane of the surfaces 34A, 34B, 56A, 56B) although thc axcs R and R' are laterally offsct with rcspect to cach other in this rcfercnce plane by a prcdctermined offsct distance 100 (Figure 1). For a fibcr the 20 offsct distance 100 is typically on the order of five (5) micromctcrs.

Tbe inlct cnd 94 of the fully funnel-like channel 92 (bcst secn in Figurcs 4 and 5) is sizcd to circumscribe and thereby to 25 accommodate a fibcr F whose cladding laycr L (or outsidc surfacc) has the largest cxpected outer diameter dimension.
The outlct cnd 96 of thc channel 92 (best secn in Figure 3) is sized to circumscribc and thcrcby to accommoda~e a fiber F
whosc cladding laycr L (or outside surfacc) has a dimension 3~ somcwhat smaller than the minimum cxpcctcd outer diameter dimcnsion of the fibcr F. ln practice, to position an optical fibcr having a nominal outer diameter dimension of one hundrcd twcnty fivc (125) micromcters, the largest cxpected outer diamctcr dimcnsion is on the order of one hundred 35 twenty ninc (129) micrometcrs while the smallcst cxpcctcd .. . . .. . . ...

Wo 93/OS4lS Pcr/u~s92/073~8 ~666~
outer diameter dimension is on the order of one hundred twenty one (121) micrometers.

The dimension~ of each of the troughs 60A, 60B is such S that the guideway 98 so formed by the registered troughs 60A, 60B is sized to accommodate a fiber F whose eladding layer L
has the largest expected outer diameter dimonsion. Despite its dimension with respect to the fiber, the guideway 98 assists in the insertion of a ffber into the positioning apparatus 20 and is 10 advantageous in this regard.

ln the embodiment shown in Figures 1 through 5 the surfaces 34A, 34B on the respective arms 22A, 22B, respeedvely, are, when in a first, closed, position, either in 15 eontaet with each other or, if desired, within a predeterrnined elose distance to each other. Por optical fibers the prede~rmined close distanee is typically on the order of five (5) to twenty-five (25) micrometers. In this embodiment the planar surfaces 34A, 34B on the abutments 32A, 32B of the 20 elips 30A, 30B are not secured to each other and may move to a seeond, ce~tering, posidon, as will be described. The planar surfaees 56A, 56B on the respecdve arms 22A, 22B are secured to each other by any convenient means of attachment, as by fusing or soldering. It should be understood that any other 25 meehanieal securing expedient may be used to attach or olerwise hold together the surfaees 56A, 56B to each other.

Tbe positioning apparatus 20 further ineludes a mounting foundation 74 (Pigures I and 2). The moundng foundation 74 30 is provided with a planar attaehment surfaee 76 thereon. A
step 78 in the mounting foundadon 74 serves to space the attachment surfaee 76 a predetermined clearanee distanee 80 from a second surfaee 82. The opposite major surface, e.g., the surface 28A, of the arm 22A is seeured, as by fusing or 35 soldering, to the planar attachment surface 76 on the :

4~5 PCI`/US92/07388 foundation 74. Of eourse, it should be again understood that any alternative meebanical attaebment expedient may be used to attaeh or otherwise hold together the seeond major surfaee of the arm to the foundation 74.
' .
Altbough the seeond surfaee 82 of the foundation is shown in the Figures as being generally planar in the preferred ease, it should be understood that this surface 82 may take any desired eonfiguration. As will be more fully appreeiated 10 herein, so long as the opposite surfaee 28A of the arm 22A
affixed to the foundadon 74 is, at least in the region of the elips 30A, spaced at Ieast a predetermined clearance distance 80 from the second surface 82 (assuming the surface 82 is parallel to the surfaee 76), the movement of the clip on the arm 22A
15 attaebed to the foundadon (in the drawings, the elip 30A) to be deseribed will not be impeded.

When assembled, the elips 30A, 30B disposed at the ends of the arms 22A, 22B, respeedvely, are supported in a 20 eantile~rered fashion from the eonjoined enlargements 54A, 54B
at the opposite ends of tbe arms. The arms 22A, 22B are ~igid in x-z plane, as de~med by the eoo~dinate axes shown in Figure 1. Moreover, the relatively ~hin dimension of the eentral region 25A, 25B of tbe base portion 24A, 24B of the arms 22A, 25 22B axially intermediate the respeetive abutments 32A, 32B
and the enlargements 54A, 54B aets as a flexure and permits each anrl 22 to flex, springboard fashion, in the direetions of the arrows 88 in the y-z plane. As used herein it should thus be appreeiated that a flexure is a spring member that is rigid in ! ' 30 one plane and is eonstrained to flex in the orthogonal plane.

lt should further be appreeiated that when a clip 30A, 30B is defleeted in its corresponding respeetive direction 88A, 88B, the resilieney of the thinner central region 25A, 25B of the 35 base 24A, 24B, aeting as a flexure, defines means for biasing 5 PCI`/US92/07388 ~666~ 28 `

the clips 30A, 30B toward tbe first, closed, position. The biasing force acts on the clip 30A, 30B in a direction shown by the arrows 90A, 90B, countcr to the direction of motion 88A, 88B of the arms. The biasing forccs must be substantially 5 equal and in opposite directions. In general, whatever the number of arms used in the positioning apparatu~, the force on each arm passes through the refcrcncc a~cis and the sum of forces wben in the centering position substantially equals zero.
Biasing means cmploying the thinncr central region of the base 10 24 as a flexure (as shown in the Figures I to 4) is preferred for all discloscd embodimcnts, bccause when implemented in a single crystal material using a microfabrication technique precise control of the biasing forces is able to be attained.
Typically the bias force on each arm is on the order of five (5) 1 5 grams.

It should be understood that any other convenient mecbanism may bc used to define the means for biasing the arms and the clips 30 thereon toward the closcd posidon so 20 long as tbe fo~ce on cach arm passes through the reference axis and the sum of forces on the arms when they are in the centcring position is substantially equal to zero. Whatever form of biasing means is selected the bias force must increase with deflection of the arm.

-o-O-o-Having dcfined the structure of the positioning apparatus 20 of the embodiment of Pigures I and 2, the operation thereof 30 in positioning a point P on the center axis and on the end face E
of an optical fiber F along a predetermined reference axis R
may be readily understood in connection with Figures through 7.

wo 93/05415 PCr/USg2/07388 29 21166~8 ln operation thc fiber F is inserted into tbe positioning apparatus 20 in the dircction of thc arrow 102 (Figure 6A).
Tbe Icad-in portions 68A, 68B (Figure 1) cooperate to guide the fibcr F into thc guidcway 98 (Figurc 2) defined by thc 5 rcgistcrcd troughs 60A, 60B in tbc cnlargcmcnts,.~A, 54B
(Figurc 1). Becausc the axis R' of the guidcway 98 is offsct from tbe axis R of thc fully funnel shaped cbannel 92 thc guidcway 98 scrvcs to guide thc facc E of the fibcr F toward tbc inlct cnd 94 of tbc channel 92 at a predetermincd azimuth 10 with rcspcct to tbc a~is R.

As a rcsult the cnd face E of the fiber F enters the channcl 92 and is inidally displaccd, or movcd, through contact with at Icast one of tbe sidcwalls 38A or 38B, 40A or 40B (or 15 portions of thc major surfacc 26A, 26B, if these are uscd to dcfinc thc groo~cs 36A, 36B, as in Figure 4) on one of the clips 30A, 30B, respccd~cly, to thc cxtcnt nccessary to move a prcdctcrmincd point P on an end facc E of tbe fibcr F toward alignmcnt with thc rcfcrcncc axis R.
At somc point on thc path of axial insertion of thc fibcr F
into thc channcl 92, as the cnd E of thc fibcr F movcs toward - thc oudct cnd 96, thc outcr diamctcr of thc cladding layèr L of thc. ~Iber P cxceeds tbe dimcnsion of thc channcl 92. Thc arms 25 22A,~-~2B rcspond to a forcc in the dircctions 88A, 88B imposcd -thcrcon by the fiber F by mo~ring against thc biasing forcc from the first, closcd, position, shown in Figures 7A, 7B, toward a second, ccntering, posidon sho~wing in Figures 8A, 8B. In the ccntcring position thc clips 30A, 30B open against thc bias 30 forcc acting in thc dircctions 90A, 90B generated by the flcxing of tbc arms 22A, 22B, to separate the surfaces 34A, 34B
thcrcon. Howcvcr, this movement of the arms 22A, 22B from tbc first toward the sccond position positions the point P on the cnd face E of the fibcr F on the reference axis R. The cnd face E
35 of the fiber F thus cxits through the outlet end 96 of the fully WO 93/OS415 PCI`/US92/07388 666Q~ 30 funnel shaped channel 92 with tbe point P preeisely aligned witb (i.e., witbin one mierometer of) tbe reference a~cis R, as is shown in Figures 8A, 8B. Tbe fiber F is beld in tbis position by eontaet with tbe sidewalls 38A, 38B, 40A, and 40B.
If the tabs 48A, 48B are formed on the abutments 32A, 32B these tabs eooperate to define a passage of unifonn width along its axial lengtb tbat eommunieates with the outlet of the funnel-lilce ehannel. The fiber F passes tbrough and emerges 10 &om sueh a eonduit with the point P on tbe end face of the fiber sdll along the referenee axis R.

lt should be noted that the movement of the arms could be other than the flexing thereof as deseribed heretofore. It 15 therefo~e lies witbin the eontempladon of this invention to have the arms mo~e in any other manner, as, for example, by any fonn of pinned or jointed (ardeulated) modon.

- o -O-o -With referenee now to Figures 9 through 12 an alternate embodiment of the posidoning apparatus 201 in aeeordanee with the present invendon is shown. In this embodiment the arms 221 are, similar to the embodiment earlier diseussed, 25 artieulably~mo~rable~in eantilevered fashion with respect to eaeh other against the bias of the flexure defined by the eentral portion 25l thereof. However, ~e grooves 36t formed in the arms 22l are not eonverging grooves, but are uniform width groo~es. Aeeordingly the chànnel 921 formed by the 30 eooperadve associadon of the arms 22l when superimposed one on the other is a uniform width channel. The maximum dimension of sueh a channel 92l in the plane perpendicular to the reference R is less than the outside diameter of the smallest antieipated fi~ber F.

Wo 93/05415 Pcr/usg2/o7388 31 2I166~8 A further modification to the positioning apparatus 201 may bc sccn from Figure 12. It is first notcd that the planar walls 621, 641 of the troughs 601 are parallel, rather than inclined with rcspcct to cach othcr. Morcover, the offsct 100 bctwccn the axcs R and R' lics in thc vcrtical plane,:that~is, in thc planc containing the axcs 701 of thc troughs 601, as opposcd to bcing offsct latcrally (i.c., in thc plane containing the surfaces 561). The lead-in portions 681A, 681B are ommittcd here but may bc providcd.
In operation, a fiber F is inscrtcd into the positioning apparatus 201 and guidcd by the passage 981 defined by the registcred troughs 601A, 601B. Bccause the axis R' cf the passage 981 is vcrtically offsct from the axis R of the channel lS 921 thc surface 261B of thc arm 221B bounding the passage 981 scrvcs to guide thc fibcr F toward thc inl~t cnd 941 of the channcl 921. Thc fibcr P enters thc channcl 921 and contacts witb the cdgcs of the sidcwalls 381A, 381B, 401A and 401B.
Duc to dle sizing of the groo~rcs 36tA, 36)B the fiber F docs not touch thc major surface 261A, 261B of the arms 221A, 221B, rcspectivcly. The fiber may be chamfcrcd or tapcred or a mecbanical device may be uscd to facilitate insertion of the ber into the channel 921.

.
Since thc fiber F cxcecds the dimension of the channcl 921 thc clips 301A, 301B arc displaccd from the first, closed, posidon toward a second, ccntcring, position. This movcment of the clips 301A, 301B maintains the point P on the end face E
of thc fiber F on the rcference a~is R. The end face E of the fiber F thus cxits through the outlet end 961 of the channel 921 with the point P precisely aligned on the reference axis R. The fiber F is held in this position by contact with the edges of the sidewalls 381A, 381B, 401A, and 401B, as indicated by the character LC.

wo 93/05415 Pcr/uss2/073ss ?,~666~ 32 -o-O-o-The cmbodimcnt of the positioning apparatus 201 shown in Figurcs 9 to 12 can be furthcr modified, as seen by the 5 positioning apparatus 202 shown in Figures 13 to,~l6; In this modification, thc arm 222B differs from those shown carlier in that no groove is provided thcrein (Figure 15). In this cmbodiment, if the groove is a converging groove, a partially funnd^lil~e channd is dcfincd. The fiber F is guided ~y contact 10 against the major surfacc 262B and held in posidon on thc rcference a~cis R by contact with the major surface 262B and the edges of the sidcwalls 382A, 382B. again as indicated by the charactcr LC.

1 5 -o-O-o-Figures 17 and 18 are cxploded and assembled pc~spectivc views, gcncr:ally similar to Figures I and 2, of anothcr altcrnatc embodimcnt of a positioning apparatus 203 in 20 accordance with thc prosent invcntion while Figurc 19 shows thc end view~ thaeo In this embodimcnt, instead of the arms bcing articulably movablc as dcscribcd carlicr. the arms ~re ~lxcd rclativc to cach other. Each of the arms 223A and 223B
has a con~rerging groovc thercin and the channel 923 formed 25 by thc coopative association of the arms 223 when supcn nposed one on the othcr is fully funnel-like in form.
Thc channcl 923 dcfincs a minimum dimension in the plane perpendicular to the reference~ R that is. near its outlet cnd, lcss than thc outside tiameter of the smallcst anticipated fibcr F.

In operation, a ~Ibcr F is inserted into the positioning apparatus 203 and guided through the passage 983 toward the inlct end 943 of thc channcl 923. l"he fiber P entcrs the funnel-liko channel 923 and is guidcd by contact with one or more of 35 ~he sidcwalls 383A, 383B, 403A and 403B and/or major '-`'-';

wo 93/054lS rCr/USs2~073s~

surfsces 263A, 263B to place tbe point P of the fibcr F on the a~cis R. Howevcr, sincc the arms 223 are fixed with rcspect to cach otbcr, tbc fibcr F can only advance within the channel 923 to tbc xial location wbcre tbe outcr diametcr of the fiber F
5 equals tbe local d mcnsion of thc cbannel 923. ~this a~cial locat on within the cbanncl tbc fiber is held in posidon by a minimum of four point contacts (indi~atcd by the characters PC) bctween thc fibcr F and cacb of thc sidewalls 383A, 383B, 403A, and 403B. ~hc dimcnsion of the channel is such that the 10 fibcr is not ablc to contact the major surfaces of the arms 223 when it is held along thc rcfercnce axis R. Figure 20 illustrates the ffber as thc same is hcld within the channe' 923 Thc axial spacing 104 bctween the cnd facc E of the fiber F and the outlct end 963 of the channcl 923 varies, dependent upon the 15 nuter diameter dimcnsion of thc fibcr P.

-o-O-o-The positioning ~pp~ratus 20, 201. 20~ and 203 in 20 accorda~ee with any of thc above-dcscribcd embodimcnts of thc invcntion may be uscd in a varicty of applications which requirc the precise posidoning of a point P on the cnd face E of a fibcr F along a refercnce axis R.

ln Figurcs 21 and 22, a pair of positioning app~atus 20-1, 20-2 (corresponding to the embodimcnt shown in Figurcs l and 2) are arran8ed to define a fiber^to-fiber conncctor generally indicatcd by the reference character 120. In this a,rrangcm~nt the apparatus 20-1, 20-2 are confrontationally disposcd with rcspcct to the other so that the outlet ends ~6 of the rcspective channcls 92 therein are spaced a predetermined distance 122 with the respective reference axes R therethrough being collinear. To effect such an arrangement the foundation 74 is cxtcnded in an axial direction and each axial cnd thereof is provided with a planar attachmcnt surface 76. Each WO g3/05415 1'Cl/US92/07388 34 `
~666~
positioning apparatus 20-1, 20-2 is mounted to its respeetive at~aehment surfaee 76.
. .
Tbe fibers F-l and F-2 to be conneeted are inserted into 5 the Iead-ins 68 of tbe respeetive positioning app~us 20-i, ~0-2. Eaeb positioning apparatus 20-1, 20-2, aeting in the manner deseribed above, serves to plaee the point P on tbe end faee E, of the respeetive fiber F-l or F-2 along tbe eollinearly disposed a~ces R. The fibers F-l, F-2 are inserted in to the 10 respeetive apparatus 20-1, 20-2 until tbe end faees E on eaeh fiber abu~. The ends E of tbe fibers F-l, F-2 are seeured due to the abo~re-deseribed holding aetion of the positioning appar2t~s. If desired an suitable index matching adhesive, sueh as an ultraviolet euring adhesive sueh that manufactured 15 and ~old by Eleetro-Lite CoFporation, Danbury, Conneetieut as number 820t)1ELC4480, may be used.

It shoold be understood that the fiber-to-~lber eonneetor may be implemented using any of the other of the above-20 diseussed alter~adve embodiments 201, 202, and 203 of thepositioning apparatus. In the event a pair posidoning apparatus 203 as shown in Pigure 17 is used ~see Figures 23 and 24), the eonfronting ends of the positioning apparatus 203-1, 203-2 are preferably abutted and secured, or the pair of 25 positioning apparatus formed integrally with each other. The spaeing 122 between~the end faces E of the ffbers F-l, F-2 is, in this embodiment, defined by the sum of the distances 104-1, 104-2. The spaeing 122 is filled with an index matehing n~aterial, sueh as the adhesive defined abo~e. To this end, an 30 aceess port 124 is provided to permit the introducdon of the index matehing material into the region between the confrondng end face of the fibers F-l, F-2.

Prior to inserdon into the posidoning apparatus (of 35 whateYer form) it sbould be understood that the jacket J

" ,~ -Wo 93/05415 Pcr/uss2/07388 (Figure 29) of the fiber F is stripped in its cntirety a predctcrmined distance ~rom the frce cnd thereof. The exposed portion of the fiber is clcaned with alcohol. The fiber is clcavcd to form tbe end face E. If desired the cnd face E may S be ground into a convcx shape to yicld a point o~be Iensed.

-o-O-o If desired the fiber-to-fibcr connector 120 may be 10 disposcd in a suitable housing 130 (Figure 25). The preferred form of the housing 130 is generally similar to that disclosed in United States Patent 4,784,456 (Smi~h), assigned to the assignee of the prcscnt invcntion. This patcnt is hcrcby incorporatcd by rcfercnce hcrcin. The housing 130 includes a 15 basc 13~ and a cover 134. The basc 132 is, in all cases, providcd with a recess 136 that is sized to closely receive the connector 120. If thc connector 120 is realized using any form of th~ positioning apparatus that articulatcs, the cover 134 must bc providcd with a corresponding recess 138 locatcd so 20 as to pcnnit the aniculadng motion of thc arms of posidoning apparatus used to form thc connector. If the conncctor 120 is rcalizcd using thc form of the positioning apparatus shown in Figurcs 23 and 24, the secess 138 need not be pro~ridcd. Such a housing 130 is sho~vn in Figure 28.
Tbe cover 134 is segmented into three sections, 140A, 140B, 140C, cach which is hingcd to the base 132. The base 132 has, adjacent to cach cnd of the rcccss 136, V-shaped groovcd ~egions 142A, 142B. The top end sections 140A, 140B
30 each contain respective gcncrally tapered lands 143A, 143B.
Each of the lands has serrations 145A, 145B respcctively thcreon.

ln usc a conncctor is inscncd in thc recess 136 of the 35 housing 130. It is thcre hcld in place by friction but may be WO 93/05415 PCI`/US92/0738~8 ~666 36 otherwise secured if desired. The central section 140C of the cover may then be closed, if desired. An optical ~Iber having a predetermined length of its jaclcet J stripped and cleaned, is inserted tbrough~ oDe of the V-shapcd grooved regions 142A, 5 142B to dispose thc stripped cnd of the fiber int,o~he connector 120. Tbc groovcd rcgion serves to propcrly oricnt and posidon the ~Iber with respect to the conncctor t20 in the rccess 136.
The associated top cnd section 140A, 140B, as the case may be, is thcn closed and latched to the corresponding portion of the 10 base 132 (Figure 25, with the fiber ommittcd for clarity).
When the top is secured to the base the serrations 145 act against the jacket of the fiber to urge, or to bias, the fiber toward the connector. A second fiber is correspoDdingly introduced into the housing and connector in an analogous 15 manncr. If not alreadv done so, the central section 140C of the covcr is then closcd. The housing 130 is preferably formed by injection molding.

As sccn in Figure 29, in another form the housing 130 20 may bc implementcd using a mass 160 of index matching material, such as that idendfied above. The mass 160 extends ovcr both the conncctor i20 ~to embed the same thcrein) and some prcdetermine.d portion of the jackets J of the fibers F-l, F-2.

- o-O -o -The reference axis R on~which the point P of the fiber F is positioned may itself extend collinearly with the axis X of any ! ~ 30 of a ~raricty of dcvices. Accordingly, a positioning apparatus 20 may be used to accurately position the point P on the end face E of the fiber F with respect to the axis ~C of a particular device 170. Figures 30, 31 and Figures 32, 33 illustrate several cxamples of the use of a positioning apparatus 20 to locate a 35 fiber F along an axis X of a device 170. The device 170 may, ~W0 93/0~415 rCI'/US92/07388 for example, be realized by any aedve optieal eomponent, such as a solid state laser, a photodiode, a light emitting diode, whether these deviees are edge aeti~re deviees or surfaee active deviees. Although in the diseussion that follows the reference 5 ebaraeter 20 is used to indieate the positioning ~ppi~ratus, it should be understood that any one of the embodiments of the positioning apparatus 201, 202 or 203 heretofore deseribed may also used.

When used in eonneetion with an edge aetive deviee 170 the a~rangement in Figures 30 and 31 is preferFed. In this arrangement the foundation 74 is axially extended to define a pedestal 174 at the axial end thereof. Tbe upper surface 176 of the pedestal 174 defines a planar attaehment surfaee. Tbe lS surfaee 176 is spaeed a predetermined distanee above the attaehment ~urfaee 76 or otherwise loeated sueh that when the ed~e opdeal eomponent 170 is mounted the surfaee 176 tbe axis X of the de~iee 170 and the referenee axis R are eollinear.
With the a~ces R and X eollinear, the posidoning of tbe point P
20 on tbc fiber F along the axis R will automatieally posidon that point P in the same relationship with the a~is X. The deviee 170 must be aeeurately mounted on the surfaee 176 so that its axis X is eollincatly aligned with the axis R.

To mount the deviee 170 the surfaee 176 may be pro~rided with a layer of solder layer, sueb as a gold/tin solder.
The de~iee 170 may have a eorresponding layer of tbe same material. The de~iee 170 is positioned on the surfaee 176 using a suitable mieroposidoning a~pparatus, sueh as a ~raeuum probe. The de iee is aligncd to the edge, heated above the melting point of the solder and cooled, so that the solder forms a bond.

When used with a surface active deYice, as seen in 35 Figurcs 32 and 33, ~e aetive surface of the device 170 is WO93/OS415 PCT~US92/07~
666~ 38 sccured to the front surface 178 of the pedcstal 174. Attaching the dc~icc to the front surface 178 iS bclicvcd to pro~ride suffieient bonding area to securc thc dcvicc 170 to the positioning apparatus 20. The surface 176 Of thc pcdcstal 174 5 is rclie~ed to avoid obstruction betwecn the actiyc.region Of the device 170 and the cnd face E of thc fibcr P~

It should also bc appreciated, as is illustrated in Pigure 31A, that thc positioning apparatus in accordance with any one 10 of thc embodimcDts herctoforc dcscribcd may bc configurcd to accuratcly position a Icns, such as a ball or a rod lens L, with rcspect to thc axis X of thc dcvicc 170 (whcther tbe samc is an cdgc acdvc or a surfacc aetivc dcvicc). The posidoning apparatus would bc modified to providc a seat 31S in tbc clips 15 30 thcreof sizcd to acccpt tbc Icns L.

-o-O-o-ID addidon to thc ~arious cmbodimcDts of thc two-anned 20 eoDfiguradoDs for the posidoning apparatus 2Q 201, 202 and 203 of thc prcscnt inwntion prcvioudy discloscd, it lics within tbc coDtcmplation of this in~rcndon for a positio~ng apparatus in aceordancc with this in~cndon to cxhibit morc than two arms 22.
ID this regard Pigurcs 34A to 34C gcnerally illustratc a posidoDiDg apparatus 204 ha~ing tbrcc arms 22A, 22B and 22C.

Figures 34D through 34F gcncrally illustratc a 30 positioning i apparatus 205 having four anns 22A, 22B, 22C and 22D. A detailcd description of an embodiment of a four armcd posidoniDg apparatus 205 is sct forth hcreinafter.

The cxtension to c~cn grcatcr numbcr of arms would bc 35 readily apparcnt to thosc s~illed in thc art.

WO 93/05415 PCI~/US~2/07388 ~9 211666~

Generally speaking, in Figure 34A each the arms a~e configurcd similar to the form of the arms discussed above.
The arms may, if desired carry a groove, although it should be 5 understood that sueh is not required. In Figures,34B and 34E
the arms are configured from rods. Although the rod~ shown as round in cross section it sbould be understood that they ean have any desired alternate cross section. In Pigutes 34C and 34F the arms are con~lgured in a generally planar bar form. As 10 will be fully set forth herein, in Figure 34D tbe four arms may be formed by sawing the upper and lower arms (indicatcd by the char;aeters 22A, 22B in Figures I to 4) along a eut line extending perpcndicular to the major surfaces 26 and 28 of eaeh of tbe arms, thereby to define upper and lower pairs of 15 arm segrnents, or "fingersn. As used in this application, the term "fmgers" is to be und¢rstood to be tbe structures defimed wben an "armn, as that term has been used herein, is subdivided into two a~cially dongated segments.

However eonfigured the arms are shown in Figures 34A
througb 34Fas angularly juxtaposed in a surrounding reladonship to the cbannel 92 defined their cooperative assoeiadon. Similar to the situation deseribed heDtofore the resilieney of tbe arms defînes the Wasing means wbich urge the ~ns toward the elosed position. However, it should be understood that the biasing means may be othenvise defined, so lo~g as the force on each arm passes througb the reference axis and tbe sum of forces on the arms when tbey are in the eentering position is substantially equal to zero. Whatever fonn of biasing means is seleeted the bias force must incresse with defleetion of the ann. The arms act against the fiber F
insened into the ehannel along the various lines of contact LC
illustrated in Figure 34 to maintain the predetennined point on the fiber on the reference axis R.
3~

WO 93/05415 PCI'/USg2/07388 666Qo 40 '"' - O- O- O -In practice, during fabdcation of tbe posidoning device misalignmcnt may sometimes occur bctwccn the first and S sccond arm in the arm pair (Figurc 1). As a rcsul~, in use, thc fibcr may bc supportcd by only two diameffically opposcd sidcwalls on the fi~t and sccond arms (scc Figure 43). Thus, thc fibcr may not be positioncd to lie along the rcfcrcncc axis.

A positioning apparatus 205 in accordancc with the embodimcnt of the invention shown in Figures 35 through 40 is bclicvcd able to avoid this result. With refercnce to these Figurcs it is secn tbat cach arm (225A, 225B. Figure 35) is itself loDgitudinally slit along slit lincs 215 thcrcby to define a set of 15 four fngcrs, 22S-l. 22S-2, 225-3, 22S-4, arrangcd into a first, upper, pair of fingcrs (225-l, 22S-2) and second, lowcr, pair of fingcr pairs (22S-3, 225-4).

As shown in Figure 36A, in a manner gencrally similar to 20 tbc ear}icr discusscd embodiments, each finger in thc sct includcs a basc portion 24S baving a f rst major surface 265 and a second, opposcd, major surface 28S. The basc portion 245 cxtends along thc full length of cach fingcr and thc dimcnsion of thc contral region 25S of thc base portion 245 2S dcf~cs thc basic dimcnsion of cach fingcr.

A clip gcncrally indicated by the rcfercnce charactcr 305 is dcfined at a first end of cach finger 22S. The clip 305 is formcd in a relatively thiclccr abutment portion 325 that lics on 30 thc first surfacc 265 of cach finger 22S. The abutment 325 has a planar surface 345 thereon that preferably lies parallel to the first maJor surface 265. Again, to provide some fceling for the physical dimensions involvcd, the fingcr 22S has an overall lcngth dimension on thc order of twenty four hundred (2400) 35 micromctcrs and a width on the ordcr of cight hundred (800) . . .~

WO 93/054lS P~/USg2/07388 - 2ll6668 micrometcrs. ln the ccntral region 255 cach finger 225 has a tbiclcncss dimcnsion on the order of one bundred (100) micrometers.

S Each abutmcnt 325 includcs a planar sidcw~ll 335 that cxtcnds in an inclined manncr (at an sngle of 5~.74) from the pcrpendicular to the major surface 265 of each fingcr. The sidcwalls 33S in the fingcrs of the first pair 225-1 and 225-2 cooperatc to dcfinc a uniform width groovc 365 while the sidewalls 33S in the fingcrs in tbc otbcr, mating, finger pair 225-3 and 225 4 also coopcrate to define a similar unifo~m width groove 36S.

Each fingcr has, at tbe cnd opposite tbe abutmcnt 325, an cnlargement gcnerally indicated by tbc rcfcrencc charactcr 54S. Thc enlargcmcnt has abutmcnts 55SA and 55SB thercon.
Eacb abutmcnt S5SA is pro~idcd with a wall 625 that coopcratcs with thc corrcsponding wall 62S on the othcr finger in tbc pair and with a portion of thc major surfacc 265 of thc basc portion 245 ncar the second end thcreof to fonn a noncon~erging, uniform width, truncatcd V-shapcd trough 605.
In thc cmbodiment shown in Figurcs 35 and 36 thc trough 605 is uniform in depth along its axial lcngth, as mcasurcd with respcct to a dimcnsion linc crccted pc~pcndicular to the surfacc 565A cxtcnding toward thc major surfacc 265. The trough bas an a~is 705 extending ccntrally and axially therctbrough. The trough 605 is widcr than the width dimcnsion of the groovc 36S. ln a morc prcferred arrangcment the trough 605 communicatcs` with a converging lcad-in 68S
dcfincd by~the cooperadve association of surfaces 695 provided on cach abutment SSSA on the fimgers in the pair.

A most prefcrrcd arrangcmcnt has two anglcd surfaces at cach Icad-in corncr of cach abutmcnt, as shown in Figure 36B.
35 Abutmcnts 325 lookcd similar to thc abutmcnts 55SA beforc a WO 93/054lS PCI~/US92/07388 cut is made lo fcrm tbe linear fronl edges of the abutmenls 325, as shown in Pigurc 36B. As will become clcarcr hcrein, the surfaces 56SA on the abutments S55A of opposcd fingcr pairs arc joincd, by any convcnient mcans of attachment, as by S fusing or soldedng. In Figure 36B thc latetal surjfaccs of tbc abutmcnts 325 and tbc abutmcnts SSSA are ranfpcd or inclincd with rcspcct to thc major surfaces 265.

Tbe surface 56SB on the thc abutmcnt 555B depcnding 10 from thc surfacc 285 is spaced a prcdctcrmined distancc 805 from tbe surfacc 285 of thc fingcr 225. As will also become clcarcr hercin, the abutmcnt 55SB thcrcby functions as a standoff to spacc thc fingcr away from a foundation or slab on which it is mountcd.
ln thc asscmbled condition, bcst shown in Figurcs 35 and Figurcs 37 tbrough 40, corrcsponding fingcrs in each pair arc disposcd in supcrimposcd rclationship onc abovc thc otbcr, witb ~c groo~c 36S and tbe trough 605 cooperativcly dcfincd 20 by tbc fingcrs in one pair rcgistering with tbc corrcsponding groo~e and trough formcd by thc cooperadvc acdon of the fingcrs in the othcr pair.

Tbc groovcs 365 formcd by the coopcrative ~ction of thc 25 fingcrs in cach pair are thcmselves registercd and tbus coopctate to define a channel 925 (Figures 35 and 39). The channcl 925 bas an input cnd 94S and an output cnd 96S. The rcfcrcncc axis R cxtcnds ccntrally and axially through thc channcl 925. Prcferably, thc`refcrcnce axis R lics in a rcfcrence 30 plane RPl containing the surfaces 565A on each finger 225 ~see Figure 38). Most prefcrably, the reference axis R also lies in a second reference plane RP2 (Figure 39) containing the slit lines 215 dcfining cach pair of fingers in the finger set. It should be understood that manufacturing tolerances can result in slight 35 misalignmcDt of axis R with respect to the reference plane RP2.

wo 93/05415 Pcr/us92/o7388 The consequences of such a misalignment will be discussed more fully hereafter.

The registered troughs 605 (and lead-ins 685, if present) 5 eooperate to define a guideway 985 (Figures 36B and 38~. The axis R' through tbe guideway 985 lies in the plane eontaining the eonjoined surfaees 565A of the abutments 55SA (see Figure 38). The plane RP2 (Figure 38) eontains the axes of the troughs.
The altes R and R' both lie in the referenee plane RPI (the plane 10 of tbe surfaees 565A) ar~d should preferably both lie in the referenee plane RP2-ln the embodiment shown in Figures 35 through 40 thesurfaees 345 on opposed eotresponding fingers in eaeh pair are, 15 when in a first, elosed, position, eitber in eontaet with eaeh otlier or may, as preferred, be within a predetermined elose distanee to eaeh otber to insute tbey will not be affeeted in joining operadons. For optieal fibers the predetermined elose dista~lee is typieally on the order of one (1) to two (2) 20 mierometers. The planar sutfaees 34 are not seeured to eaeh other and thus may move to a seeond, eentering, position, as will be deseribed.

As seen in Figure 35 the positioning appatatus 205 25 funher ineludes, in the preferred instance, a mounting slab 745 baving a planar attaehment surfaee 765 thereon. Tbe surface S6SB of the abutment 55SB on each ftnger 225-3, 225~ is secured, as by fusi~g or soldering, to the planar attaehment surface 765 on tbe slab 745. Owing to the presenee of the 30 abutment 55SB, the surfaees 285 on the fingers 22S-3, 225~ of ~he lower pair are spaeed the distance 805 from the attachment surface 765. lt should be understood that the abutment 555B
may be omitted, and the lower fingers 225-3, 225-4 may be mounted to a foundation 74having a step 82thereon similar to 35 that shown in Figure 1, in order to provide the clearance , , ,, ., ., . , ., ... . . , . , . ,, . , .. , . . ~ .. . ., . . . ~ . .. .

wo 93/054lS Pcr/us92/o7388 ~,~666Q~ 44 di~tarlee 805 neeessary to permit -lhe movement of the lower fingers in eaeh pair. The fingers 225-1, 225-2 in the upper pair of fingers may also be seeured. as by fusing or soldering, to the planar attaehment surfaee 765 on a seeond slab 745. The 5 seeond slab 74S is shown in outline in Figure 3S; _ When assembled, as shown in Pigure 35, the clips 305 disposed at the ends of the fingers 225 are supportcd in a eandlevered fashion from the eonjoined enlargements 54S at 10 ahe opposite ends of the fingers. Eaeh of the fingers 225 is relatively tigid in x-z plane, as defined by the eoordinate axes sh~wn in Figure 35. Moreover, the relatively thin dimension of the eentral region 255 of the base portion 245 of each finger 225 axially intermediate the respeetive abutments 325 and the 15 enlargements S4S aets as a flexure and permits the elips 305 at the end of eaeh finger 225 to flex, springboar~ fashion, in the direetions of tbe arrows 885 in the y-z plane. Again, as the term is used herein, a flexwe is a spring member that is reladvdy rigid in one plane and is constrained to flex in the 20 orthogonal plane.

lt should further be appreciated that when a clip 305 is défleeted in its eorresponding respective direetion 885 the resilieney of the thinner eentral region 255 of the base 245, 25 aeting as a flexure, defines means for biasing the fingers 225 and the elips 305 thereon toward the first, elosed, position. The biasing foree acts on eaeh elip 305 in a direetion shown by the arrows 905 eounter to the biasing direetions 885. It should be understood that any other eonvenient meehanism may be used 30 to provide the means for biasing the clips 305 toward the elosed posidon. The biasing forces must be substantially e4ual and in opposite d*eetions. Biasing means employing the thinner eentral region 255 of the base 245 as a flexure is, however, again preferred beeause when implemented in a 3~ single l:rystal material using a microfabrieadon technique WO 93/05415 PCI~/US92/07388 ., ~ 45 2116668 precise control of the biasing forccs is able to be attaincd.
Typically thc bias force on cach finger is on the order of twenty (20) grams.

-o-0-o- `

Ha~ing dcfined the structure of thc positioning apparatus 205 in acc~rdance with this cmbodimcnt of the invcntion, the opcration thercof in positioning a point P on thc center axis and 10 on Ihc end face E of an opdcal fiber F along a predctermined refercnce axis R may bc rcadily understood in connection with Figures 38 through 43. As mentioned earlier. and as is clcarly ~isiblc in Figure 41, whcn positioning thc poh2t P intG
alignmcnt with Ihc reference axis R thc positioning apparatus 15 actually contacts thc fiber at contact points Iying a closc distancc from thc end facc E.

Assuming tbat the referencc axis R (Figure 39) of the channd 92 aligns with both thc ff~rst and sccond rcfcrencc 20 plal~es RPl, RP2 (Figurc 38), the operation of thc positioning dc~nce 205is substantially idcntical with the operation of the positioning devicc shown and discusscd earlicr in connection with Figure 6 through 8. Thus, thc fiber F is inserted into the positioning apparatus 20S in the direction of thc arrow 1025 ~2S (Figwcs 37, 41). Thc fibcr F is inse~ted into the guideway 985 - dcfincd by tbe registered troughs 605. Thc fiber F cnters the channel 925 and is initially displaced, or moved, through contact with at Icast one of the sidcwalls 335 or portions of the major surfacc 265 used to define the groo~cs 365 on one of the 30 clips 305 to thc extent necessary to accurately place a p~edct~amined point P on an end facc E of thc ffber F toward a1ignmcnt with the rcfcrence axis R.

.
Since the outer diameter of the cladding layer L, shown 3S on Figures 41 and 42, of the fiber F cxcceds the dimension of .

wo 93/05415 PCI/USg2/07388 Q~ 46 ~ ~i the channel 765 formed by the sidewalls the fingcrs 225 respond to a deflecting force in the direcdons 885 imposed thereon by the fiber F by displacing from the first, closed, position (shown.~in Figure 39) toward a second, centering, 5 position shown in Figures 42 and 43. In the cen~ering position the clips 305 open against the bias force acting i'n the directions goS generated by the flexing of the fingcrs 225 to scparate the surfaccs 345 thereon. This movement of the finger 225 from the first toward the second position accurately positions the 10 point P on the end face E of the fiber F in alignment with the reference axis R. The end face E of the fiber F thus exits through the outlet end 965 of the channel 925 with the point P
accurately positioned in alignmen~ with the reference axis R, as is shown in Pigures 34 and 42. The fiber F is held in this 15 position by contact with the sidewalls 33S.

-o-O-o-As alluded to earlier, in somc instances, owing either to 20 misalignment bctwecn arms (before they are slit to form finger pairs), misalignmcnt bctwcen the slit lines 2lS in each finger pair and the dcsired location of the slit lines on cach arm, mismatcbes of finger thiclcness, and/or mismatchcs of finger widths, the asscmblcd position of the superimposcd fingcr 25 pairs will appcar as shown in Pigure 43. Diametrically opposite sidewalls 33S on diamctrically opposite abutments 325 are not equally spaced from the refcrence axis R. The misalignment of the anns (prior to slitting to form finger pairs) is indicated by the rcfercnce character Ma. `The misalignment of resulting slit 30 lines 2lS is indicated by the reference character MS.l and MS-2-The mismatches of finger thickness is indicated by the reference character M~. The mismatches of finger width is indicated by the reference character Mw.

W093/05415 rCI/US92/07388 ~ 211~668 - ;;
As seen in Pigure 43 whcn a fiber F is inserted into the cba~ncl 925 formed from arms or fingcrs with such misalignment(s), the fiber F will first strilce a first, and then the sccond, ~3f two diamctrically opposed ramping lateral surfaces S of the Icad-ins of the abutmcnts 325 (Pigure 36B~ before contaclting the sidcwalls 335. These initial contact Doints on the fingors 22S-2, 225-3 are illustratcd in Figure 44 at refcrence characters 3351. Those sidew~lls 33S first contacted by the f~ber F are forcedl apart in the dircctions 935A, 93SB. However, 10 since tbe bias forces generated by the movcmcnt of the first contactcd sidewalls are opposite, the fiber F becomes centered in an interim centered position in a plane parallel to and centrally bctwccn such two surfaces. This interim centered position lies at some point in the plane indicatcd in Figure 44 15 by thc line dcnoted at rcfcrcnce character Pl.

Continucd advancement of t~e fibcr P through the channcl 925 causcs thc outcr diamcta of the fiber F to touch onc or both of tbe rcmaining sidcwall pair. The fust touch of 20 Ibc fiber to the sidcwalls 335 jS not thc f~al position of tbe fibcr. The final position of the fibcr is achieved when the two fingers on the sidcwall pair 225-1, 225-4 (l;igure 44) have moved sufficicntly to center the fiber. These final contact points are illustrated in Figurei 44 at reference characters 335F-25 Since the bias forccs created by movement of these last twosidewalls are also equal and oppositely directcd thc fiber is finally centered on the intersection of the plane Pl and another p1ane PF. The plane PF plane is parallel to and centrally located between the two surfaces touched at the contac~ points 335F-The final position of the fiber F may bej displaced ~romthe desired reference axis due to the misalignments defined earlier and to other variations within manufacturing tolerances as described bdow. To malce a positioning apparatus, or a 35 connector or an opto-electronic component utilizing the same, WO 93/05415 P(~/US92/07388 ~2~ 48 ~;

for typical single mode optical fibers, the posidoning apparatus must bc ablc to handle fibcrs ranging in diametcr from 125 to 128 micrometcrs. This range is found to be the typicat diametcr variation in quality single mode fibcrs.
S ,~
To insure tbat a fiber is hcld propcrly by all four fingers in thc most prcfcrrcd cmbodimcnt (Figurcs 35 to 45) the alignmcnt,of wafcrs for bonding during the fabricadon process to bc discusscd must limit variadon of thc misalignmcnt in thc 10 dircction across tbc groovcs (thc dimcnsion M, of Figurc 43) to + or - 9.5 micromctcts. This dirccdon of misalignment rcduces tbc rangc of fibcr diamctcr variadon tbat arc handlcd in thc most prcfcrrcd cmbodimcnt. Tbe misalignmcnt of wafcrs in tbc othcr dirccdon, along thc Icngth of thc rcfcrcncc axis 15 sbould bc no morc tban twcnty (20) micromctcrs. This dirccdon of misalignmcnt rcsults in tbc clamping points of one pair of side-by-sidc ~mgcrs bcing axially displaccd from thosc points of thc othcr pair of sidc-by-sidc ~mgcrs, which would tend to bcnd thc fibcr sligbtly upwardly or downwardly.
Thc misalignment of thc slit or saw cut, (Ms in Figurc 43) must be no morc than ten (10) micrometers to avoid cutdng into a sidcwall of a groovc whcn thc slit width is sixty-six (66) , widc; as obtained by using a typical sixty (60) 25 micromctcr saw.

Tbc thiclcness of the flexure portion of the fingcrs should not vary by more than + or - three (3) micrometcrs so spring forccs ~,vill be balanced with the fibcr ccntcrcd.
Commonly hcld tolcrances in the microfabrication arts, such as in the microfabrication of dcYiccs as pressure rupture discs, arc wcll within the above rangcs. ln fact, assuming the usc of an cnhanced positioning apparatus having an alignmcnt ::

WO 93~05415 PCl`tUSg2/07388 2 1 1 6 1~
clamp, as shown in Pigure 45, estimates show, in practice, the above maximum variations would result in +1- 5 micrometers for sidewise misalignment, Ma, +/- 1.5 micrometers for for fle~cure thiclcness M~, +/- 10 mictometers for axial misali,gnme~ts~ of wafers.
Other variatdons such as flesure width aud friction encountered when a fiber is centered by acdons of the four fingers are small. The net result using commonly achievaUe manufacturing tolerances for microfabricated parts is well under one (1) micrometer in displacement of the center point on the end face of the fiber &om alignment with the reference axis. Even for the maximum ~ariadons discussed above, the displacement of tbe center of the fiber end face from alignment with tbe desired reference axis is well under one (1) 1 5 micrometer.

-o-O-o -Witb reference to Pigures 42 and 44 (whether the ~mgers are mismatched or not) since the fiber is supported only at points of contact between each of the fingers in each finger pair, the Iength of the fiber behind the eontacts is free to pivot.
To a~oid this eventuality it is desirable to enhance the ability of tbe positioning apparatus to precise position a ffber into alignment with a reference axis. To this end, it lies within the contemplation of tbe present invention ~o provide a clamp, generally indicated by the reference cbaracter 220, for engaging the fiber a predetermined distance 224 along tbe referenee a~is from the vicinity of the points of contact between the fiber F and the fingers 225. Such an enhanced positioning apparatus 205E is shown in Figure 45.

As is best seen in Figure 45, tbe enhanced positioning apparatus 205E comprises a f*st, forward, positioning apparatus 205 a~d a clamp 220 disposed a predetermined .... , ... . . , . , .. . .. ; ... . , ... . " .. . . .. .. ..

WO 93/05415 PCI~/US92/07388 Q~ 50 - distanee 224 behind the positioning deviee 205. The clamp 220 is preferably implemented using a seeond posidoning apparatus 205. However, any other of the positioning apparatus 20, 201, 202. 203 or 204diselosed herein may be 5 used as the elamp 220. Moreover, the elamping funetion may be performed by any a~rangement of suitable form.

It is, of course, understood tbat an enhaneed positioning apparatus similar to that sbown by referenee eharaeter 205E in 10 Pigure 45 may be obtained using a forward and rearward arrangement of positioning apparatuses. Any eombination of positioning apparatus 20, 20', 20", 203, 204, or 205 as disclosed herein may be used tO implement the forward positioning apparatus and the elamp, thereby to form an enhaneed 15 positioning apparatus 20SE.

The elamp 220 serves to position aeeurately a point on the eenter axis of the fiber into alignment with the referenee axis. Tbis seeond point on the eenter axis of the fiber is spaced 20 a _ncd distanee from the end faee of the ~Ibcr. By providing the elamp 220, any angular misalignment between the flber axis and the referenee axis is held to a minimum.

-o-O-o -It should also be apparent, similar to the situa~iondiselo$ed in Figures 30 through 33, that a positioning device 205 or an enhaneed positioning apparatus 205E in accordance with this invention ean be used with an edge aedve or a 30 surfaee aetdve opto-eleetronic device to define an opto-eleetronic eomponent.

In sueh a usage, the slab 745 would be extended, in the manner shown in Pigures 30 and 31, to provide a pedestal 35 similar to the pedestal 174, on whieh an edge active device 170 wo~3/os4ls 2116 6 6 3 Pcr/usn/073ss may be mountcd. Tbe dcvice 170 may be mountcd to thc pcdestal in the manncr earlicr discusscd. Alternadvely, the slab may be modified to providc a pedcstal similar to that shown in Figures 32 and 33, to accept a surfacc acdve dc~ice 5 170. As is the casc in thc earlicr, the device 170_may take the fotm of a solid state lascr, a photodiode, or a light emitting diode, whether thcse devices are cdge or surface acti~re. The axis X of the de~rice is collincar with the rcference a~cis of the posidoning apparatus 205 so ~at a fiber aligned by the 10 apparatus 205 with the rcfcrence axis will be in alignment with the dcvice 170. The positioning apparatus 205 may be modiftcd as suggcsted in Figure 31A, if desired, to acccpt a Icns.

1 5 -o-0-o-If it is dcsircd further, it should be appreciated that the positioning apparatus 205 or an cnhanccd positioning apparatus 205E in accotdancc with this invcndon can be used 20 to fashion a connector apparatus for holding the facial ends of two confronting fîbcrs cach in alignment along a predetcrmincd common reference axis.

To ~is cnd it is advantageous to mount onto the slab 745 25 a two confrontadona11y disposed positioning apparatuses 205 or two confrontationally disposed enhanced positioning apparatuses 205E, (or a combination of the same).

The connector arrangement of positioning apparatuses 30 205 or apparatuses 205E may be disposed in a suitably adapted housing gcne~ally similar to that shown in Figures 25 to 28, it being understood that the reference character 120 in Figures 25 to 29 indicates a connector formed of confronting apparatus 205 or apparatuses 205E. Most preferably, the housing should 35 be fabricated material with a low thermal coefficient of '':

WO 93/05415 PCI~/US92/07388 ".,`.~, ~ 666~ 52 expansion over a temperature range &om (~5 F to + 8S F).
A suitable preferred material is a liquid erystal polymer such as that sold by Hoeehst Celanese Corporation under the mark "Veetran. Codvendonal molding proeesses for that polymer can 5 be used to form tbe housing. ~_ -o-O-o-The photolithographic microfabricadon technique used to 10 manufaeture a posidoning apparatus in aeeordanee with this invention may be understood from the following diseussion taken in eonneetion with Figures 46 to 52. Although the diseussion is east in terms of the manufaeture of a fiber-to-~Iber eonneetor using the preferred embodiment of the 15 enhaneed positioning apparatus 20sE as shown in Figure 45, the ~chings are readily extendable to the manufaeture of any of the embodiments of the positioning apparatus heretofore deseribed, ineluding their use in tbe various other applications pre~iously set forth. (For elarity of deseripdve text, the basic 20 referonee eharaeters (i. e., without superseripts) of the elements of the positioning apparatus are used.) ~ A silieon wafer 200 having an appropriate predetermined erystallographic orientation is the starting point for fabrieation 25 of ~c arms 22 of a positioning apparatus 20 in aceordance with the present invention. It should be understood that other single erystalline substrate materials, sueh as germanium, may be used provided appropriate alternative etehants and materials eompatible with the seleeted alternative substrate 30 are used. The wafer 200 is polished on at Ieast one surface.
Suitabh sUieon wafers are available from SEH America, Inc., a subsidiaq of Shin-Etsu Handotai Co. Ltd., Tokyo, Japan, located at~ Sparta, New Jersey. It should be understood that the wafer 200 ean be of the "p-type", "n-type" or intrinsic silieon.

wo 93/05415 Pcr/uss2/073ss The substrate mateAal is preferably (100) surface silieon beeause this material ean be etehed by anisotropic etehants wbieh readily act upon tbe (100) erystallograpbie plane but substantially do not eteh the (111) plane. As a result the 5 preferred truneated V-sbaped grooves 36A, 36B,, the t~oughs 60A, 60B, the lead-ins 68A, 68B and tbe eentraI' region 25A, 25B of the arms 22A, 22B between the abutments 32A, 32B
and the enlargements 54A, 54B are easily formed. Tbe width and depth of sueh features are dependent upon the preseleeted lO width of the opening in the pbotolithographic mask being used and tbe time during whieh the etchants are permitted to act.
Etehants operate on 100 surface silicon in an essentially self- -limidng manner which property is useful in forming a full V-groove. One of skill in the an will reeognize that if other 15 etoss-seedon eonfigurations are required, other predetermined erystallographie orientations of the silieon may be used. For e~cample, if square eross-seetion features are desired, (110) surfaees silieon wafas ean be used. Other eross seedonal esnfiguradons for the features are, however, signifieantly more 20 e~cpensive and, as will be seen later, would require a more eomplieated eonfiguration to obtain the ~lber eentering aedon equivalent to that inherent in a V-groove.

Figure 46 Is a plan view of the wafer 200. The wafer 200 25 has pcripheral fl~ts 201 and 202, as speeified by the SEMI -Standard. Tbe flats 201, 202 p~imarily indieate orientation of tbe erystallographie strueture of the silieon and are also uscd for wafer identifileadon and mask alignment. The longer flat 201 indieates the dircction of erystallographic plane (110).
30 The shorter flat 202 is plaeed a predetermined angular amount on the periphery of the wafer with respeet to the flat 201, ~he magnitude of tbe angle depending upon the doping of the erystal.

WO 93/05415 PCI~/USg2/07388 54 ".
,666~
As will be dcveloped, the pcripheral rcgions 203 of the wafer 200, when prepared, carry alignmcnt featurcs, while the central region 204 of the wafer 200 has the structural fcatures of the ann or foundation, as the case may be, of the posidoning 5 appalatus formed thereon.

Figure 47 shows a mas~ 210 with a pattcrns 212 of alignment featurcs, such as orthogonal alignment grooves or alignment through holes 212H and corrcsponding wells 212W, 10 thercon. The holcs 212H arc etched from the oppositc surface of thc wafer as are the wells.

If grooves are used, the grooves in each pattcrn 212 are graduated in size to accommodate various sized (diameter) 15 quartz alignment fibers. The grooves 212 have a V-~haped cross section to acccpt fibcrs ranging ir~ width from about 0.004825 incbcs (0.123 mm) to 0.005000 inches (0.127 mm) in 0.039370 inch (0.1 mm) steps, ffve groo~rcs 212 having been illust~ated. Thc groove width (at thc open top of the groove) is 20 largcr than the diameter of the fibcr so that the center of the fiber is substantially coplanar with the surface of thc wafcr when thc fibcr is disposed in its associatcd groove.
Accordi~gly, for a 0.123 mm fibcr, a groove 0.1506 mm is providcd. Similarly, for a 0.124 mm fiber, the open top 25 dimension of tbe groove is 0.1518 mm. ~or a 0.125 mm ~Iber, the open top dimension of the groove is 0.1531 mm; for a 0.126 mm ~lbcr the open top dimonsion of the groove is 0.1543 mm.;
and for a 0.127 mm ~lber, the open top dimension of the groove is 0.1555 mm.
A central area 214 of the mask 210 has provided thereon a repctitive pattern 220 (one of which is shown in Figure 48) containing to a predetermined number of structural features (i.e., arms or foundations mor slabs) of the positioning 35 apparatus 20 bcing formed. Since the typical wafer 200 is about 3.9381 inches (101.028 mm) in diameter and a typical conncctor 120 measures about tbree hundred fifty (350) micrometcrs at the widest location and is about two thousand dght hundred (2800) micrometers in Icngth, the structural 5 f~a~,ures for approximately one thousand (1000,~ connectors 12~ may be forrncd from thc ccntral region 20~ of the wafer 200.

Figure 48 is an enlarged vicw of a portion 220 of the 10 pattern provided on the ccntral region 214 of the mask 210.
In Figure 48, the pattern illustrated is that used to form a plurality of conjoincd anns 22 used in a connector 120. The pattcrn 220 is formed on the surface of the central region 214 of the mask 210 using a well-lcnown step and repeat proccss to 15 covcr the entire area.

Tbc rcpctitivc pattcrn 220 shown in Figure 48 is compriscd of a plurality of columns 224 which are def~incd bctween an array of adjaccnt parallel scribe lincs 226 and a 20 ~lrst and a second scparadon linc 227A and 227B. Each column 224 contains tcn (10) discrcte zones 228A through 228E that are symmetrical within the column 224 about a cutting line 230.

Seen bctween two next adjacent scribe lines 226 is the conf1guration of two arms 22 joincd front end to front cnd.
Scen bctween thrce next adjaccnt scribe lines 226 is the configuration of two anns 22 joined lengthwise side to side.
The zonc 228A corresponds to fcatures defining the region of Ithe Icad-in 68A of an arm 22A. The zone 2:28B corresponds to featur~s defining the region of the trough 60A of the arm 22A.
Similarly, zone 228C corresponds to the central portion 25A of the arrn 22A, while the zone 228D corresponds to features dcfining the region of the converging groove 36A on the arm 35 22A. The axis 50A of the converging groove 36A is offset from wo 93/05415 rcr/us92/07388 ?~ the axis 70A of tbe trough 60A by the offset distance 100.
Pinally, if provided. the zone 228E corresponds to fcatures de~lning the region of the tabs 48A of an arm 22A. Note that in the mask illustrated in Figure 36 the position of the offset 100 5 on one side of the cutdng line 230 is reversed fro~n the position of thc offsct 100 on the opposite side of thc cutdng line, although this arrangement is not nccessariiy requircd.

Tbe repedtive pauern for a mask of the arm 22B will be 10 similar to that shown in Figure 48 except that the direction of the offset distanccs 100 for the arm 22B will be the mirror imagc of the pattern for the arm 22A. As will become clearer herein, this mirror image relationship between the offsets is neccssary so that so that features on the resulting anns 22A, 15 22B will registcr with each other when one is inverted and superimposcd on the othcr. Of course if the offset 100 is eliminatcd, masks for the arms 22A and 22B will be identical.

Tbe cross-hatched areas shown in Pigure 48 preferably 20 corrcspond to those areas of the central region of the wafer 200 that will be protected by a layer of resist material (as will be dcscnbed) while the areas shown without hatching will be Icft unprotected during subsequent etching steps. A ncgative rcsist is cmployed but it should be apparent that the lo ation of 2~ the hatched and clcar arcas of Figure 48 may be revcrscd if desircd. This would alter somewhat subsequent steps, but in a manncr known to those in the art.

Pigures 49A through 49E iilustrate the process steps 30 whcrcby a wafer 20Q of crystalline silicon may be formed into an array of arms 22A corresponding tO the array shown on the mask of Pigures 47 and 4~. As seen in Figure 49A the wafer 200 is preliminanly covered with a layer 232 of a material that acts in a manner similar to a mas~;. Silicon dioxide (sio2) is 35 prcfcrred, and is surfaced onto the polished operative surface Wo 93/05415 ~ uss2/073ss .
200S of the silicon wafer 200 by thermally growing the silicon o~cidc layer in an oxygen atmosphcrc at devated temperature (circa eleven hundrcd fifty (1150) dcgrees Celsius), as is Icnown. As indicated, silicon oxidc is used becauæ a~.railablc 5 ctchants that attack silicon will also attack Icno~n photorcsists but will at~ack thc oxidc only slightly. This sli~t attack is accounted for when dimcnsioning the photomasl~.
-The layer of silicon oxide 232 is then co~rered with a 10 photoresist 234. Preferred is a positivc resist, such as themixturc of 2-ethoxyethyl acetate, N-butyl acetate and xylene sold by Shipley Company, lncorporated of Ncwton, Massachusetts, as "Microposit Photoresist" 1400-37. The resist is spun onto the surface of the silica dioxide in accordance with 15 ins~rucdons set forth in the Shipley Microelectronic Products Brochure (1984) using standard apparatus such as that avdlable from Heàdway Rescarch Incorporated of Garland, Te~tas under modcl number ECR485.

The mask 210 is mountcd atop the wafer 200 and is aligncd with respect to the flats 201, 202 of thc wafcr 200 using alignment bars 23~. Thus, in a fimished wafer the alignment grooves 212 are preciscly positioned with respect to thc flats on the wafcr through the use of alignmcnt bars 213 on the madc. The wafer 200 is cxposed to ultra~riolet light through the mask 210 and subsequently developed.

Since a positive resist is used the unexposcd areas of the rcsist are washcd away using dc-ionized water, leaving the SO ! layercd arrangement of cxposed, hardened resist 234, silicon dioxide 232 and wafer 200, as shown in Pigure 49B.

Next the pattern of the mask 210 is etched into the silica layer 232. Buffer hydrofluoric acid (HF) is preferred. This step 35 results in the a~rangement slbown in Figure 37C. Those slcilled wo 93/05415 Pcr/uss2/o7388i 6 in the art will recognize that process variables such as, for - example, concentration, dme and temperature are all adjusted appropriately to opdmize results in all of the wet proccssing -stcps describcd.

Tbercaftcr, a second, differential, ctcbing s'tep is pcrformcd to etch the silicon to form the fcatures of the arms 22A. Tbe prcfcrrcd anisotropic etchant is tcn perccnt (10%) potassium hydrcxide (KOH). Ethylcne diamine ("ED") 10 pyrocatcchol ~nP") and watcr, in a mix of 750 ml ED, 120 gm P
and 240 ml watcr, may be uscd. This ctching produccs thc structural fcature in the surface of the silicon illustratcd schcmadcally in Figure 49D by refcrence character 236. The dcpth of the feature 236 is controlled by controlling the ctching 15 dmc, as is wcll Icnown. Of course, diffcrcndal etching is sclf-limiting for the insidc anglcs of thc structure, if left to procced.

The silicon dioxide laycr 232is thcn rcmo~cd by ctching with buffcr hydrofluoric acid (HF) and anothcr laya of silica, 20 i.c., silicon dioxidc, is grown on thc surface. Ncxt, rcsist is dcpositcd on thc surfacc of thc wafcr and is imaged through a maslc, as shown Figu;re 38. This results in a layer 238 of bardcned resist bcing formed on those prcdetennincd portions of the wafer thiat are to bc bondcd (corresponding ~to zoncs 25 228C through 228E and to troughs 60 (see Figure 36)).

The silica layer is then ctched ~rom arcas that are to be bonded (See, Figure ~9E) using hydro~luoric acid (HF). The resist layer 238 is stripped using acetone, leaving a finishcd 30 wafcr rcadyi for bonding.

This completes the fabrication of the first wafer 200 having the array of arms 22A thereon.

-o-O-o-:::

., As notcd earlier, si~ce tbe axis of the guideway 98A may be offset rom the axis of the groove 92A, the mask for the arms 22B may not be identical with the mask used to form the 5 arms 22A. Accordingly, a sccond wafer having an array of arms 22B thcreon may be preparcd in accordan'ce with the mcthod steps illustrated in Flgure 49. Tbe finishcd sccond wafer (not specifically illustrated but hereinafter referred to by character 200') is similar in all respccts cxcept in location of lO the offset 100. f thc wafcrs are the samc, the second wafcr is prcparcd cxactly as the first.

A third wafer 200" is prepared using a foundation mlask, a portion of which is shown in Figure 51. Pigllre 51 is an 15 cnlarged view of a portion of the pattcrn 220' providod on the ccntral rcgion of the foundadon maslc (analagous to the pattern of thc arm mask shown in Figute 36). The repe.titive pattern 220' is comprised of a plurality of columns 244 which are dcfincd bctwecn an array of adjaccnt parallel scribe lines 246 20 and a first and a second separation linc 248A and 248B. Each column 244 contains four (4) discrcte zoncs 250 that are symmctrical within the column 244 about a center line 252.
The zoncs 250A dcfine mounting surface 76 on a foundation 74. Thc zoncs 250B correspond to the surfaces 82 providod on 25 the foundation. The wafer 200" containing the foundations 74 is exposed in a manner analogous to that shown in Figure 37, with the cxccption that the exccption that the solder mask exposure is not carried out. Howcver, the layer of silica is removcd from the surface of the wafer 200n.
3 ~) Having prepared wafers for the arms 22A (the wafer 200), the arms 22B (the wafer 200') and the foundations 74 (the wafer 200"), the final assembly of the connector 120 may be made as is shown in Pigure 40.

WO 93/05415 PCl'~US92/07388 Q~ 60 '^`
~666 Tbe wafer 200' is placed on top of the wafer 20.
Prcferred methods of aligning wafers to be joincd involve etcbing holes that go through one wafer and wells (shallow bolcs) on the mating wafer accurately located by the precision 5 photomasks used for ctching so that wafers are aligned by matching through hole with well at at Icast two l'ocations on each wafer. One mcthod involves etcbing truncated pyramidal through-holes and wells so that when one wafer is turned over and placed against the sccond wafer, each bole and well can be 10 matched by obscrvation with a microscope as the wafers are posidoncd with precision adjustmcnt mcchanisms as are well Icnown in the micromachining art. A bctter method is to etch V-grooves forming crosses as holes and wells and matching by infrarcd source and camera scarching for the brightcst image 15 madc by a bcam passing through both wafers. Such infrarcd cquipment is commcrcially available, (as, for cxample, &om Rcsear~h Dcviccs Division of Amcrican Optical Corporation) a most prcfcrrcd method is to ctch a grid pattcrn of lincs spaci:-g from each othcr on tbe ordcr of ten (10) micromet*s 20 scparadon. ~n infrarcd bcam image can be inspectcd for the brigbtcst and most uniform lincs in the imagc wherc etched linc are aligncd Ictting the most infrarcd beam through the two silicon wafcrs. (This latter method is bclicvcd to bc accurate to 0.5 micromctcr, as comparcd to the method with 25 crosscs whicb is accurate to, typica11y, ten (10) micromcters .

As yet anothcr alternative, the registration of the fcatures on the wafcr 200' to those on the wafer 200 is cffoctcd using at least two and preferably four lengths of a 30 stripped optical fiber and the corresponding appropriate one of thc aligDmcnt groovcs in cach array 212 of grooves. The diamcter of each length of the optical fiber is measured by micromctcr, accurate to plus or minus 0.5 micrometers. Each of thc fibas is placcd in groove in the groove array 212 that most 35 closely corrcsponds to the measurcd diameter. Each alignment WO 93/05415 PCI~/US92/07388 - 21I6~68 fibcr thus sits in the selected alignmcnt groove such that the axis of the alignment fibcr lics in thc plane of the surface of tbe wafcr 200 with the remaining portion of each fibcr protrudes abovc that surfacc.
Tbe wafer 200' is invcrtcd ~nd placcd atop thc wafer 200, with the corrcsponding grooves in thc wafer 20~' rcceiving the protruding portions of the alignmcnt fibcrs thereby to precisdy align the pattern of the two wafcrs. Since 10 thc alignment grooves on cach wafcr are formcd simultancously with the formation of the fcaturcs on the wafer, and since the mask for cach wafer is formed opdcally one from the othcr, precise alignment bctween the wafers is achieved. lt is notcd in Figurcs 40A and 40B only onc of the fibers 254 and 15 groovcs 121 is shown, for clarity of illustration.

In a lcss prcfer~cd mcthod, thc asscmbly of superimposcd wafers 200, 200'~ shown in Figurc 52 is bondcd in a wct controlled atmospbcrc futnacc accotding to mcthods 20 dcscnbcd in tbe papcr by Shimbo et al., "Silicon-to-silicon ditcct bonding method" publishcd 10/86 in the Journal of Applied Physics, and in the papcr by Laslcy ct al., "Silicon on lnsulator (SOI) By Bonding and Etcbb~clcn, IEDM 85. As sccn in Figurc S2B tbc cxtcrior surfacc 256' of thc wafcr 200' is lappcd 25 to rcducc its thichlcss from it original tbickncss (typically approximatcly scventecn (17) mils) to a final tbiclcness of five (5) mils.

The more prcferrcd method of bonding uscs tbe above 30 but avoids expensivc lapping by ctching parts of thc arms and ~mgers as dcscribed bclow. and avoids forming an abutment on the slab.

Thc rcsulting bondcd structure is invcrted and the 35 cx~èrior surface 256' of thc wafcr 200' is mountcd atop tbe WO g3/0541S PCI~/US92/07388 62 ~""

wafer 200". The alignmcnt of thcse wafers is cffected using a fixture cmploying quartz bloclcs 260 abutdng against the flats 201, 202 of the wafcr 200. Thc wafer 200' is then bonded to the wafer 200n. It is to be understood that otber bonding 5 tcchniques, sucb as thosc discusscd in the papcr by Wallis and Pomcrantz "Ficld Assistcd Glass-Mctal Scaling" puUisbed 9/69 in thc Journal of Applicd Physics may be used to bond tbe wafcrs. Stdll other altcrnate bonding tcchniqucs would includc mctallic or glass soldcr bonding.
Tbe cxtcrior surface 256 of the wafcr 200 is then lapped until thc dimcnsion of tbe wafer 200 is that of the wafer 200'.
Thus, the substandal equality of the biasing forces imposed by tbc ncxure is providcd.
The rcsultant tbrec wafer bonded stack shown in Figure S2D may hcn bc cut. Only thc top two wafas 200, 200' of the bondcd stack (containing tbe arms 22-lB, 22-2B and the arms 22-lA, 22-2A, rcspecdvcly, Pigurc 22) are first cut along the 20 lincs in thc wafcrs corrcsponding to the cutting lincs 230, 230' on thc arm maslcs (Pigure 36). This cut is made using a Uade tbat is on the ordcr of 0.003 inches to crcate the distance 122 in Pigure 22. The bondcd stack is thcrcaftcr cut, using a blade tbat is 0.015 incbcs tbick, along tbc lincs in the wafcrs 25 corrc~ponding to thc scparation lines 227A, 227B on the wafer 200, tbc scparation lincs 227A', 227B' on the wafer 200', and tbe scparatio~ lines 248A, 248B on the wafer 200n, as well along tbe scribe lines 226, 226' and 246 (on the respective wafers 200, 200' and 200") ali of which are rcgiste~ed with 30 cach otber, thcreby to yield from the bondcd stack about one tbousand of the ~Iber-to-fiber connectors 120.

-o-O-o -WO !~3/0541~ PCI~/US92/073~8 6 3 2 ¦ 1 6 ~ 6 8 As noted earlier, the positioning apparatus 205 shown in Figures 35 through 44 or an cnhanced positioning apparatus 20SE shown in Figure 45 (and any connector or opto-electronic made using the same) is fabricated in a manner generally 5 similar to th~t previously discussed in the case of the positioning apparatus 20. Some specific points G~ be notcd.

A portion of the top surface of a wafer defines the surface 565B of a fingcr pair whcn fabricadon is complctcd. An 10 adjoining portion of ~be wafcr is ctched to fonn tbe surface 285 of cach finger pair.

On tbe opposite side of the wafer, a portion of that s0facc becomcs surface 56sA of cach abutmcnt 545, whilc 15 anotber portion of that wafcr surface is etched to form surface 34S of tbe abutmcnt 325 of cach clip 305. An adjoining portion of tbat surface of thc wafcr between thc surfaces 565A and 34S
is ctchcd slightly to form the major portion of the surface 265 defining the flcxurc. The abutmcnts S4S, 325 are also ctched to 20 form sidcwall surfaces 625, 335 respectively. Each sidewall surface 625, 335 dcfines an angle of 54.74 degrees from the plane of the wafer due to the silicon crystal structure.

It is notcd that the ctching process usod docs not malce 25 sharp corners ~t the ends of a groove. What would have been a corner is etchcd inward on each dde thercof. Due to ~e crystal structure of the silicon two anglcd faces are formed at a corner location as shown in Figure 36B. The right angle corners shown in the Figure are formed by s`awing or cutting. The bevclcd 30 comers formed are advantageous since they serve as guides to bdng a cylindrical object, as the fiber, into the channels 905 and 925 formed by the troughs 605 and the grooves 365, respectively.

WO 93/0541~; PCl'~USg2/07388 ,. . ~

66 Several finger pairs are ctched in a single silicon wafer.
All etching is done before the other fabrication stcps.

A wafer containing containing a prede~ermined numbcr of unscparated of fingcrs is positioned on top of another wafer containing a corrcsponding predetcrmincd numbc'r of unscparated of fingcrs. The wafers arc aligncd so that the surfaces 565A (see Figures 36A) of the unseparatcd fimgers on cacil wafer surface are touching in contact. The slight ctching of cach wafcr ~elievcs the surfaces 345 on cach unseparated finger to prevcnt their touching and being joined.

The two wafers containing the unseparated fingcrs are placed on a third wafer which contains a number of ~nscparated slabs 74S.

Tbe wafers arc joincd, only at surfaccs 565A, by hcating, to fusion temperature in an oven. Known methods of joinder such as soldcring can also be uscd.
After the joining steps are complctcd the silicon wafers are sliced or cut, (i) down the centcrs of the grooves 905, 925 (through the abutments 3~5 and optionally, but preferably through tbe abutmcnts 545) lo separate cooperating sets o~
fingers, (ii) to separate sets of four fingers which will beeome positioning appa~atus, and (iii), to cut the bottom wafer. The bottom wafer may ~e separated to define a moundng slab for a set of four ~ingers to serve as a positioning apparatus (as in Figurc 35), to contsin a both a forward and a rearward sct of 3G ~ur fingcrs to define as a positioning apparatus with a rearward clamp (as in Figure 45), or to contain two confrontationaly disposed positioning apparatus, (each of which may include a single positioning apparatus, or a positioning apparatus having the fo~vard and reanvard finger set.

WO 93/05415 ~ : PCI`/US92/0?3&8 o O-o-Those slcilled in the art, ha~ing the bencfits of tbetcacbi~gs of the prescnt in~vcntion as hcrcinsbo~c sct forth, 5 may impart numcrous modifications thcrcto. It, should be undcrstood thu such modificadons as bcrdn 'prcscntcd and any othcrs are to be construcd as Iyi~g within thc contcmpladon of tbc prescnt invcndon, as defined by the appcndcd claims.
WHAT IS CLA~D IS:

Claims

1. (Amended) A positioning apparatus for positioning a point on a cylindrical member along a predetermined reference axis, the positioning apparatus comprising:
at least a first and a second arm, each arm being movable from a closed position to a centering position, each arm having a first axial end and a second axial end thereon, in the closed position the arms cooperating to define a channel having a reference axis therethrough, the channel having an inlet end and an outlet end, means for biasing each of the arms toward the closed position such that the force on each arm passes through the reference axis and such that the sum of forces on the arms when in the centering position is substantially equal to zero, the first axial end of each of the arms being securable to remain a first predetermined radial distance from the reference axis while the arm occupies both the closed and the open positions.
the second axial end of each arm being disposed the first predetermined radial distance from the reference axis while the arm occupies the closed position, the second axial end of each arm being displaceable radially outwardly to a second, greater, radial distance from the reference axis while the arm occupies the centering position, each of the arms being arranged such that a cylindrical member introduced into the inlet end of the channel with the axis of the member spaced from the reference axis is initially displaceable by contact with at least one of the arms to place a predetermined point on the member toward alignment with the reference axis, the second axial ends of each of the arms being responsive to further axial movement of the member through the channel by moving radially outwardly with respect to the reference axis against the bias force toward the centering position thereby to maintain the point on the member on the reference axis.
2. (Amended) The positioning apparatus of claim 1, further comprising:
a third arm movable from a closed position to a centering position, the third arm having a first axial end and a second axial end thereon, in the closed position the third arm cooperating with the first and the second arms to define the channel, the biasing means also biasing the third arm toward the closed position such that the force on the third arm passes through the reference axis and such that the sum of forces on the three arms when in the centering position is substantially equal to zero, the first axial end of the third arm being securable to remain a first predetermined radial distance from the reference axis while the third arm occupies both the closed and the open positions, the second axial end of the third arm being disposed the first predetermined radial distance from the reference axis while the third arm occupies the closed position. the second axial end of the third arm being displaceable radially outwardly to a second, greater, radial distance from the reference axis while the third arm occupies the centering position, the third arm being arranged such that a cylindrical member introduced into the inlet end of the channel with the axis of the member spaced from the reference axis is initially displaceable by contact with at least one of the three arms to place the point on the member into alignment with the reference axis regardless of the diameter of the cylindrical member, the second axial end of the third arm also being responsive to further axial movement of the member through the channel by moving radially outwardly with respect to the reference axis against the bias force toward the centering position thereby to maintain the point on the member on the reference axis.
3. A positioning apparatus for positioning a cylindrical member comprising:
a first and a second arm, at least the first arm having at least a first and a second sidewall cooperating to define a groove therein, the arms being arranged in superimposed relationship, each arm being movable from a first, closed position to a second, centering, position, means for biasing each of the arms with a substantially equal and oppositely directed biasing force toward the first, closed position, in the closed position the arms cooperating to define a channel having a reference axis therethrough, the channel having an inlet end an outlet end, each of the arms being arranged such that a cylindrical member introduced into the inlet end of the channel with the axis of the member spaced from the reference axis is initially displaceable by contact with at least one of the arms to move a center point on an end face of the member toward alignment with the reference axis, the arms being responsive to further axial movement of the member through the channel by moving against the bias force toward the centering position to position the point on the end face of the member into alignment with the reference axis by contact between the member and both the first and the second arms.
4. The positioning apparatus of claim 3 wherein the first and the second sidewalls in the first arm cooperate to define a converging groove therein, the channel being partially funnel-like in shape over at least a predetermined portion of its axial length.
5. The positioning apparatus of claim 4 wherein the second arm has a planar surface thereon.
6. The positioning apparatus of claim 3 wherein the second arm has at least a first and a second sidewall disposed therein, the first and second sidewalls in the second arm cooperating to define a converging groove therein, the converging groove in the first arm and the converging groove in the second arm cooperating to define the channel, the channel being fully funnel-like in shape over at least a predetermined portion of its axial length.

7. The positioning apparatus of claim 3 wherein the first and second sidewalls in the first arm cooperate to define a groove having a uniform width dimension throughout its length, the channel being rectangular in cross sectional shape over at least a predetermined portion of its axial length.
8. The positioning apparatus of claim 7 wherein the second arm has at least a first and a second sidewall disposed therein, the first and the second sidewalls in the second arm cooperating to define therein a groove having a uniform width dimension throughout its length, the uniform groove in the first arm and the uniform groove in the second arm cooperating to define the channel, the channel being rectangular in cross sectional shape over at least a predetermined portion of its axial length.
9. The positioning apparatus of claim 8 wherein each sidewall of the groove in the first arm and each sidewall of the groove in the second arm has an edge thereon, the edges of the sidewalls contacting the member.
10. The positioning apparatus of claim 7 wherein the second arm has a planar surface thereon and wherein each sidewall of the groove in the first arm has an edge thereon, the edges of the sidewalls contacting the member.
11. The positioning apparatus of claim 3 wherein each arm has a trough disposed therein, the troughs in the arms cooperating to define a guideway for guiding the member therebetween.
12. The positioning apparatus of claim 11 wherein the guideway has an axis therein, the axis of the guideway being offset from the axis of the channel by a predetermined distance.

13. The positioning apparatus of claim 3 wherein biasing means comprises a reduced thickness portion in each of the first and the second arms, the reduced thickness portion defining a flexure in each arm which, when each arm is deflected by contact with the member, generates a force on each arm to bias each arm toward the closed position.
14. The positioning apparatus of claim 3 further comprising a foundation, the first arm being mounted to the foundation.
15. The positioning apparatus of claim 14 wherein the foundation and the first and the second arms are each fabricated from a crystalline material.
16. The positioning apparatus of claim 3 wherein the first and the second arms are each fabricated from a crystalline material.
17. The positioning apparatus of claim 3 wherein each of the arms has a major surface thereon, a portion of the major surface connecting the first and the second sidewalls and cooperating to define the groove therein, wherein the groove so defined in each arm has a truncated V-shape.
18. The positioning apparatus of claim 6 further comprising a foundation, the first arm being mounted to the foundation.
19. The positioning apparatus of claim 18 wherein the foundation and the first and the second arms are each fabricated from a crystalline material.
20. The positioning apparatus of claim 6 wherein biasing means comprises a reduced thickness portion in each of the first and the second arms, the reduced thickness portion defining a flexure in each arm which, when each arm is deflected by contact with the member, generates a force on each arm to bias each arm toward the closed position.
21. The positioning apparatus of claim 20 wherein the first and the second arms are each fabricated from a crystalline material.
22. The positioning apparatus of claim 6 wherein each of the arms has a major surface thereon, a portion of the major surface connecting the first and the second sidewalls and cooperating to define the groove therein, wherein the converging groove so defined in each arm has a truncated V-shape.
23. The positioning apparatus of claim 6 wherein each arm has a trough disposed therein, each trough being disposed on an arm a predetermined distance behind the groove in that arm, in the closed position the troughs in the arms cooperating to define a guideway for guiding the member toward the channel.
24. The positioning apparatus of claim 23 wherein the guideway has an axis therein, the axis of the guideway being offset from the axis of the channel by a predetermined distance.
25. A positioning apparatus for positioning a cylindrical member comprising:
a first and a second arm, each arm having at least a first and a second sidewall thereon, the sidewalls in each arm cooperating to define therein a converging groove, the arms being fixed in superimposed relationship with the grooves therein cooperating to define a first fully funnel-like channel having a reference axis therethrough, the first funnel-like channel having an inlet end and an outlet end, the arms being arranged such that a cylindrical member introduced into the inlet end of the first funnel-like channel with its axis spaced from the reference axis is displacable by at least one of the sidewalls to move a center point on an end face of the member into alignment with the reference axis where it is there held by contact with the first and second sidewalls of both arms, each of the first and the second arms includes a trough therein, each trough being disposed on an arm a predetermined distance behind the groove in that arm, in the closed position the troughs cooperating to define a guideway for guiding the cylindrical member toward the inlet end of the channel.
26. The positioning apparatus of claim 25 wherein each of the arms has a major surface thereon, a portion of the major surface connecting the first and the second sidewalls and cooperating to define the groove therein, wherein the converging groove so defined in each arm has a truncated V-shape.
27. The positioning apparatus of claim 26 wherein the first arm is mounted to a foundation.
28. The positioning apparatus of claim 25 wherein the first arm is mounted to a foundation.
29. The positioning apparatus of claim 28 wherein the first and second arms and the foundation are each fabricated from a crystalline material.
30. The positioning apparatus of claim 25 wherein the first and second arms are each fabricated from a crystalline material.

31. A positioning apparatus for positioning a cylindrical member having an outer diameter falling within a predetermined range of diameters, the positioning apparatus comprising:
a set of four fingers, each of the fingers having a sidewall thereon, each finger being articulably movable from a first, closed, position to a second, centering, position, in the closed position the sidewalls of the fingers cooperating to define a channel having a reference axis therethrough, the channel having an inlet end and an outlet end, means for biasing each of the fingers toward the first, closed position with a predetermined biasing force such that the sum of the biasing forces on the fingers when the fingers are in the centering position substantially equal zero, each of the fingers being arranged such that a cylindrical member introduced into the inlet end of the channel with the axis of the member spaced from the reference axis is initially displaceable by contact with the sidewall on at least one of the fingers to move accurately a center point on an end face of the member toward alignment with the reference axis, each of the fingers being responsive to further axial movement of the member through the channel by deflecting against its biasing force to position the center point on the end face of the member into alignment with the reference axis by contact between the member and a point of contact on each of the fingers.
33. The positioning apparatus of claim 31 wherein each of the fingers is axially elongated and has a first and a second axial end thereon, and wherein the sidewall is disposed at the first axial end, each finger having a reduced thickness region disposed thereon intermediate the first and the second axial ends, the reduced thickness portion defining a flexure in each finger which, when each finger is deflected by contact with the member, generates a restoring force on each finger to bias each arm toward the closed position.
34. The positioning apparatus of claim 33 wherein the fingers are arranged into a first and a second pair of fingers, each pair of fingers being mounted to a slab.
35. The positioning apparatus of claim 31 wherein each of the fingers is fabricated from a crystalline material.
36. The positioning apparatus of claim 31 wherein the fingers are arranged into a first and a second pair of fingers, at least one pair of fingers being mounted to a slab.
37. The positioning apparatus of claim 31 further comprising:
an alignment clamp for engaging the member at a predetermined distance along the reference axis from the vicinity of all of the contact points on the sidewalls of the fingers, the clamp engaging the member so as to position accurately a predetermined second point on the center axis of the member into alignment with the reference axis.
38. (Amended) The positioning apparatus of claim 37 wherein the alignment clamp comprises:
a second positioning apparatus itself comprising:
a second set of four fingers, each of the fingers in the second set having a sidewall thereon, each fingers in the second set being articulably 39. (Amended) The positioning arrangement of claim 38 wherein each of the fingers in the second set is axially elongated and has a first and a second axial end thereon, and wherein the sidewall is disposed at the first axial end, each finger in the second set having a reduced thickness region disposed thereon intermediate the first and the second axial ends, the reduced thickness portion defining a flexure in each finger in the second set which, when each finger in the second set is deflected by contact with the member, generates a restoring force on each finger in the second set to bias each such finger toward the closed position.
40. (Amended) The positioning arrangement of claim 39 wherein the second positioning apparatus is mounted to the slab.
41. (Amended) The positioning arrangement of claim 38 wherein each of the fingers in the second set is fabricated from a crystalline material.
42. (Amended) The positioning arrangement of claim 38 wherein the fingers in the second set are arranged into a first and a second pair of fingers.