CA2194986A1

CA2194986A1 - Face-lock interconnection means for optical fibers and other optical components, and manufacturing methods of the same

Info

Publication number: CA2194986A1
Application number: CA 2194986
Authority: CA
Inventors: Sang K. Sheem
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-07-18
Filing date: 1995-07-18
Publication date: 1996-02-01
Also published as: AU3490095A; EP0771432A1; EP0771432A4; WO1996002861A1; JPH11502314A; CN1158169A

Abstract

A novel means for interconnecting optical fibers (1), (2) or waveguide channels is disclosed, in which two matching surface contours are fabricated, one contour (7), (8) on the plane containing the end face of the fiber or the waveguide channel, and the other contour (9), (10) on a surface to which the optical fiber or waveguide channel is to be mated. The matching surface contours are face-locked in a stable and unique position when the two surfaces are brought to each other, thereby positioning the end of the optical fiber or waveguide channel on a pre-determined location on the mating surface. The matched surface contours may be created on the end facet of the optical fiber (1), (2) itself, or on the outwardly-extended surface of the end facet. The same interconnection means may be applied for connecting other optical components such as lenses and light sources. Modular approach is feasible in which a combination of face-lock embodiments are stacked together to align these optical components.

Description

PcTlus95/o9296 ~P~ S 15FE3~996 ~ Desclription FACE-LOCK INTERCONNECTION MEANS FOR OPTICAL FIBERS
AND OTHER OPTICAL COMPONENTS. AND MANUFACTURING
METHODS OF THE SAME

Technical Field This invention pertains generally to the field of optical components, and particularly to means for interconnecting optical 0 fibers and other optical components.

Background Art Optical fibers have been used widely for many applications, most notably for optical fiber communication. In 1 980's the 5 optical fiber communication was mostly for linking the telephone central offices. In such an application, one optical fiber carries typically thousands of telephone (voice) channels, and the cost of the fiber optic components such as fiber-to-fiber connector and mechanical splice is not a critical issue. However, as the optical 20 fiber communication is inching toward individual offices and residential area, especially as a part of information superhighway infrastructure construction, the cost of such components become the major issue. Actually this issue is at the present time the most serious stumbling block in constructing the information 2 5 superhighway infrastructure using optical fibers. The cost should come down by a factor of about ten before optical fibers can be deployed widely.

The cost of optical fiber connectors and mechanical splices are 30 high due to the small size of the optical fiber cross-section. The same is true for mating optical fibers to integrated optic planar channel waveguides. Single-mode fiber, the most-commonly used fiber, has about 9-micron core surrounded concentrically by about 1 25-micron cladding. When two single-mode fibers, or a single-3 5 mode fiber and a waveguide channel, are mated, the cores, or thechannels should be aligned within one or two micron in terms of A~JlENDEr' StlE~

~CT~US 95 / 0 9 2 96 2 IPEAJ~ 5 F E~ 1.996 the transverse offset. In order to accomplish such a mating between optical fibers, each of the fiber is inserted in a tubing or plug with about two or three millimeter (1 millimeter = 1,000 microns), and about 125 micron inside diameter (ID). The alignment is typically achieved by aligning the plugs inside another tubing called sleeve. This requires that the size of the hole or bore of the sleeve be larger than the diameter of the plug by one or two microns, that the hole or bore of the plug be at the center with better than one or two microns, that the size of the 0 bore be larger than the fiber diameter by only one or two microns, that the fiber diameter be 125 microns plus or minus one or two microns, and that the core be located at the center of the fiber within one micron or better tolerance. All these tight dimensional requirements drive up the cost of the optical fiber connection, and to some degree the cost of the optical fibers as well. Connection of an optical fiber to a channel waveguide ( such as found in an integrated optic modulator or a planar waveguide coupler) has a very similar technical difficulty, which results in a very high cost. These costs would never be low enough for wide applications so long as all these requirements should be satisfied for optical fiber connections.

Similar technical difficulties exist in connecting other optical components such as laser diode, light emitting diodes, and lenses.
2 5 These interconnections are often found in various fiber optic-related packages. For example, a light from a laser diode is coupled to an optical fiber end via a focusing lens. The alignment of these components require better than one-micron accuracy along the optical axis.

Disclosure of Invention Accordingly, it is the primary objective of the present invention to devise an alternative approach for mating optical 3 5 fibers, waveguide channels, light sources, lenses, etc.

~4~NOEO c~

US95 / 09 29f~
~PEA~U~ 1 5 ~ Ei~ ~96 It is the ultimate objective of the present invention to lower the interconnection cost for optical interconnection involving optical fibers, integrated optic waveguides, light sources, detectors, lenses, and other related optical components so as to maximize the contribution of the fiber optics to the construction of information superhighway infrastructure.

The basic approach of the present invention for connecting an optical fiber to another optical fiber or any other optical devices is 1 o to provide a surface contour on the end facet, or on the extension of the end facet, of the optical fiber, and to provide a matched surface contour on the end face, or on the transverse extension of the end face, of the other optical fiber or the optical devices. The surface contours of the end faces are designed to be locked in a stable mating position when the two surfaces are brought together. This novel mating mechanism is named "Face-Lock" in this invention disclosure. The surface contours preferably consist of fine features, with the dimensions of the width and the depth of the fine features comparable to that of the optical fibers, so as to have alignment resolution in the order of microns or better.

Photolithographic techniques may be employed to generate surface contours with sub-micron accuracy. Similar manufacturing methods may be applied to integrated optic waveguide end-facets, 2 5 and other optical devices that require optical interconnections.

A modular approach is possible in the present invention in which a selected combination of face-lock embodiments are stacked together, one on top of the other, to align a number of optical elements.

Brief Description of Drawings FIG. 1 shows schematically two optical fibers in the end-butt 3 5 alignment positions.

E0 S~

~JIUs95/o9 296 IPFAI~ F~t996 FIG. 2 shows schematically the optical fibers of FIG. 1 housed in connector plugs in an conventional alignment embodiment.

FIG. 3 shows a sectional view of the embodiment of FIG. 3.
5across the U-U' plane.

FIG. 4 shows the basic embodiment of the present invention for achieving the alignment of the two optical fibers shown in FIG. 1.

FIG. 59 shows a thin-slab with a face-lock features and a through-hole for terminating an optical fiber.

FIG. 60 shows the sectional view of FIG. 59 across Z-Z'.
FIG. 61 shows the same as in FIG. 59, except that there are many through-holes for an array of optical fibers.

FIG. 62 shows the sectional view of FIG. 59 across Z-Z' in which 20 the face-lock feature and the through-hole are fabricated by preferential etching on a ( 100) silicon wafer.

FIG. 63 shows the same as in FIG. 62, except that the face-lock feature and the through-hole are fabricated on the opposite sides 25 of the (100) silicon wafer.

FIG. 64 shows the masking step in the fabrication process of making the alignment v-groove shown in FIG. 62 or 63.

30FIG. 65 shows the face view of the embodiment shown in FIG.
64.

FIG. 66 shows the etching step in the fabrication process of making the alignment v-groove shown in FIG. 62 or 63.

A~ENDED Sf - ~T

J ~ ~ 'J '7 ~
IpF~Jl~S 1 ~ F E~ 1996 FIG. 67 shows the same as shown in FIG. 66, except that the masking layer is stripped off.

FIG. 68 indicates that the same process shown in FIGS. 64 through 67 can be used to make a through-hole as well as the alignment groove.

FIG. 69 shows the face view of the embodiment shown in FIG. 68.

FIG. 70 is the same as shown in FIG. 68, except that the etching masks are laid down on the both sides of the silicon wafer so as to realize the embodiment shown in FIG. 63.

FIG. 71 shows the same as shown in FIG. 63, except that more than one through-holes are fabricated.

FIG. 72 repeated the face view of the through-hole of FIG. 69.

FIG. 73 shows one set of three through-holes with slightly .
varylng dlmenslons.

FIG. 74 shows a two-dimensional array of the set of through-holes and corresponding alignment grooves located on the both sldes .

FIG. 75 shows a matched pair of an alignment groove and an alignment ridge.

FIG. 76 shows two recessed alignment grooves and a cylindrical face-lock insert in-between.

FIG. 77 shows the sectional view of three alignment grooves of FIG. 74.

~NEN~)E~ SHE~T

6 P~ NS 15~B1996 FIG. 78 shows that the same as shown in FIG. 77, except that the alignment was shifted by one notch.

FIG. 79 shows that four pieces of face-lock embodiments are stacked together, one top of the another, for optical alignment between a light source, a lens, and an optical fiber.

FIG. 80 shows the same as shown in FIG. 79, except that the path of light from the light source is shown in a schematic 0 manner.

FIG. 81 shows schematically the essence of the face-lock mechanism of the present invention.

FIG. 82 shows sectional views of one connector part in a switching embodiment of the present invention.

FIG. 83 shows a second connector part corresponding to the connector part illustrated in FIG. 82.

FIG. 84 illustrates one possible mating position of the connector parts shown in FIGS. 82 and 83.

FIG. 85 shows a second possible mating position of the connector parts shown in FIGS. 82 and 83.

FIG. 86 shows a third possible mating position of the connector parts shown in FIGS. 82 and 83.

FIG. 87 shows sectional views of one connector part in another switching embodiment of the present invention, in which a set of v-squares are used for channel selection.

FIG. 88 shows a second connector part corresponding to the connector part illustrated in FIG. 87.

EN~)0 S~EET

~CTlUS 95 / 09 ~ 96 7 IP~ 1 5FE~1996 FIG. 89 illustrates one possible mating position of the connector parts shown in FIGS. 87 and 88.

FIG. 90 shows a second possible mating position of the connector parts shown in FIGS. 87 and 88.

Best Mode For carrying Out the Invention FIG. 1 shows in a highly schematic manner two optical fibers 0 ( 1 ) and (2) in an end-butt connecting position. The light (depicted as arrows) being guided by the optical fibers is largely contained inside the cores (3) and (4). The region outside the core is called cladding, and it has a lower index of refraction so as to provide an optical barrier or wall around the light-guiding core. The connection or mating is to accomplish the transfer of the light from one optical fiber to the other. When the mating is releasable, it is called demountable connection, or simply connection.
Hardware that aids such connection is called an optical fiber connector or simply a connector. When the mating is meant to be permanent, it is usually called a permanent splice or simply a spllce.

FIG. 2 shows the fiber (1) housed in a conventional connector plug (5), and fiber (2) in another identical plug (6). The plug is typically a cylinder with a hole or bore. FIG. 3 shows the sectional view of FIG. 2 across the U-U' plane. Let's denote the diameter of the fiber (1) as "F", and that of the core (3) as "C". The diameter of the plug is denoted as "P" and the bore size by "H".

3 o In assembling the optical fiber ( 1 ) and the conventional connector plug (5) as shown in FIG. 2, the hole of the plug (5) is filled with liquid-form cement material, and the fiber 1 is inserted through the plug hole until its end sticks out of the hole by a few millimeters. After the cement material is solidified, the end of the 3 5 plug (5) is polished until the fiber ( 1 ) and the cement material are flush at the end facet. The second plug 6 is prepared in the same FF

way. The two plugs (5) and (6) are inserted in a tubing called sleeve, and are mated in a face-to-face fashion.

The difficulty of mating of two optical fibers as described above, and the resulting high cost of fiber connection, may be understood if the typical dimensions for C, F, H, and P are listed for the most commonly used optical fibers: C=9 microns, F=125 microns, H=(125 + 1 or 2) microns, and P = 3,000 microns = 3 mm.
In FIG. 1 or FIG. 3, the 9-micron (C) cores (3) and (4) should be 0 aligned within one micron in order not to suffer from a substantial light loss in the mating. In order to satisfy such a tight alignment requirement, all the dimensions listed above should be accurate within one micron or so, and the core (3) and the hole of the plug (5) should be concentrically located within one micron or so. Even with such tight tolerances satisfied, the worst-case misalignment can be as large as a few microns as the deviations can add up in an unfavorable manner.

The implication of the conventional mating method and the 2 o resulting tight tolerances as described above is quite detrimental.
The optical fibers should be drawn within one or two microns from the nominal diameter of 125 microns, meaning that any fibers outside this specification will be rejected. This drives up the fiber cost. The connector plugs and the sleeve should be fabricated 2 5 with the same resolution. The plug outside diameter P, and the sleeve's hole size, are typically 2,000 to 3,000 microns plus or minus one or two microns. Thus one or two micron tolerance is translated into less than 0.1% of the diameter. This results in high fabrication cost and low yield. In addition polishing of the plug -fiber assembly adds to the overall cost. Today, the material cost for a set of connector for single-mode fibers is over 50 dollars.
Connectorization labor cost itself costs almost as much. In comparison, a typical connector for electronic coaxial cable is available at two or three dollars at retail stores, and the 3 5 connectorization procedure is very simple. The high cost of optical ~r ~ SH~E~

21 q4986 r.~ u~5/~929~
9 IPEA~)S 1 5 F E B 1996 fiber interconnection spells a disaster in an effort to use optical fibers in the often-touted national information superhighway.

We notice that the conventional connector and splice are based on alignment of the side walls, namely inside and/or outside of the cylindrical surfaces of the optical fiber, the plug and its bore, and the bore of the sleeve. This element make it necessary to maintain those inner and outer diameters within one or two micron accuracy.

Avoiding these detrimental aspect of the conventional fiber interconnection methods, the connector and splice embodiments of the present invention are designed around the optical fiber end facet, instead of the side walls. The essence of the present invention is depicted in the general term in FIG. 4. In FIG. 4 are shown four elements: an optical fiber ( 1 ) with its end terminated, a first surface (7) residing on the plane coinciding with the end-facet of the optical fiber (1), another optical fiber (2) to be connected to the optical fiber ( 1), and a second surface 8 residing 2 o on the plane coinciding with the end-facet of the optical fiber (2).
The first surface (7) has an unique contour on it, while the second surface (8) has another unique contour that may be locked to that of the first surface (7) in a stable position when brought together.
The optical fibers (1 ) and (2) are located in pre-determined 2 5 locations on the first and the second surfaces, (7) and (8), respectively in such a way that, when the two surfaces (7) and (8) are surface-locked into the matching position, the optical fibers ( 1 ) and (2) are aligned properly. The present invention as depicted in FIG. 4 will be described below in detail using various examples of possible embodiment.

An important embodiment of the present invention is shown in FIG. 59, in which a thin-slab has face-lock feature (115) (see FIG.
60 for its sectional view across Z-Z': the detailed shapes of the 3 5 grooves and the through-hole can be different from shown) and a through-hole (116) through which an optical fiber (117) is AMEtl~DE~ ~ ,.ET

P.CTIU~95 / 09 29~
o IPEAJUg ; ~ F F ~ ~96 terminated at the surface of the thin-slab (114). The alignment of the optical fiber in mating depends on the precise registration of the through-hole (116) with respect to the surface-lock feature (115). And the size of the through-hole (116) should be very close to the diameter of the optical fiber (117). This is a technical challenge by itself. However, it will be easier and cheaper to achieve such dimensional control on a planar thin-slab as shown in FIG. 59, when compared to the conventional approach as sketched in FIGS. 2 and 3.
Once the embodiment as shown in FIG. 59 can be fabricated, it is straightforward to extend the embodiment and the fabrication technique to a multi-fiber array embodiment as shown in FIG. 61, in which an array of optical fibers (118) are terminated on a thin-slab (119). This array capability is another powerful advantage of the present invention compared to the conventional plug-sleeve approach which cannot be readily extended to an array embodiment.

One manufacturing method for making the embodiments shown in FIGS. 59 and 61 will be now described. The fabrication is based on the well-known preferential etching of a silicon wafer with either (100) or (110) facet. For example, on a (100) silicon wafer, v-grooves can be fabricated in which the side walls of the v-groove have a definite angle with respect to the surface regardless of the groove size. Utilizing the technique, a v-groove (120) and through-holes (121) and (122) as shown in FIGS. 62 and 63, respectively, can be fabricated on the surfaces of (100) silicon wafer (123), realizing the embodiment shown in FIG. 59. The detailed fabrication steps are as follows: as indicated in FIG. 64, a mask layer (124) is patterned on one side and another layer (125) on the other side (this second mask is to prevent etching of the back side) on the silicon wafer using photolithography technique, which has sub micron resolution in positioning a desired pattern on a pre-determined position. The face view of the section shown in FIG. 64 is sketched in FIG. 65. Then the wafer (123) is ~N~E~ S~EE~

~CtlUS 9~ / 0 9 2 9 IP ~--immersed in an etchant that etches the wafer in <100> direction much faster than in < 111 > direction (by a factor of about SOO to 1,()00) . The etchant etches the silicon material into the < 100>
direction, that is in the direction perpendicular to the wafer surface. The side-walls inside the v-groove (120) shown in FIG. 66 are the hard-to-etch facets, namely the (111) facets. Accordingly, the depth of the V-groove depends solely on the width W of the opening of the mask (124). The masks (124) and (125) are stripped off when the etching is completed. The mask layer (124) 0 may be modified as shown in FIG. 68 to fabricate two V-grooves (120) and (121). The face view of the section shown in FIG. 68 is shown in FIG. 69, which indicates that the larger v- section (121) is a tapered square hole with four (111) side walls. This square groove (121) is actually too large to remain within the wafer body (123), as indicated in FIG. 68, and thus punch through the wafer, forming a through-hole (121) as desired (see FIG. 62). Again, the angle of the side walls are universally the same as it is defined by the (111) facets of the silicon. Accordingly, if the size of the hole W2 and the wafer thickness T are known, the value for the mask opening W3 can be calculated. The separation S between the V-groove (120) and the thorough-hole (121) may be replicated with better than O.S micron accuracy.

Since the optical fiber (117) is entering from the left side of the through-hole as shown in FIG. 59 in our example, it would be convenient to have the through-hole tapered out to the left side of the wafer, as shown in FIG. 63. This can be realized by modifying the mask layer (125) on the left-side as shown in FIG. 70, in which etching is done on the both sides of the wafer (123). The separation S can be precisely registered by using a mask-aligner that uses infrared light with see-through capability, which allows viewing simultaneously the both sides of the wafer during the mask pattern registration before exposure. The mask layer (124) in FIG. 70 may be made of a transparent, thin-film dielectric material such as glass. It does not have to be removed since it may work as a window for optical fiber being inserted in the ~MENOE~ cET

12 ~PE~I.~ EB 199 through-hole (122). The window may be one or two micron thick.
FIG. 71 shows a straightforward extension of the embodiment and the technique described in FIG. 64 through 70 to an array form, in which two through-holes (126) and (127) are prepared in the same manner for aligning two optical fibers (128) and (129).
When the window (124) described in FIG. 70 remains in embodiment shown in FIG. 71, the end facet of the optical fibers (128) or (129) may be glued to the window.

0 When the through-hole (121) or (122) in FIG. 69 or 70 are fabricated, the hole clearance W2 should be very close to the diameter of the optical fiber for precision fiber alignment. The through-hole (121) of FIG. 69 is shown separately in FIG. 72. For a given value W3, the value for W2 could vary slightly due to the variation of the thickness T of wafer (123) and undercut of the masked edges by the etchant. For example, the hole clearance W2 could turn out to be anywhere between 124 and 130 microns while the optical fiber diameter itself can vary between 123 to 127 microns. In the worst case the hole size W2 could be larger than an optical fiber by seven microns, or the hole size W2 could be smaller than the fiber diameter. In order to accommodate this variations in the hole size and the fiber diameter, a number of through-holes with varying dimensions can be fabricated, as depicted in FIG. 73, which shows three through-holes (130), (131), and (132), which have three different sizes of mask openings W3, W3', and W3", and three corresponding sizes of the through-holes W2, W2' and W2" (as examples, these three values could be 127, 125 and 123 microns, respectively) . One of these three through-holes would match to a given optical fiber better than the other holes . The number of holes may be more than three . The resulting embodiment is shown in FIG. 74, which is a variation of the surface layout shown in FIG. 61: each of the through-holes in FIG.
6 l is replaced by three through-holes in FIG. 74. There are also three sets of the face-lock grooves 133, 134 and 135. The face-lock grooves are used to align two connecting embodiments as shown in FIG. 74. The matching grooves may be designed as AMENDED Si. LT

P~lUS95/09 296 IPEA/~JS 1 5 f EB 1996 shown in FIG. 75 (a recess (120A) and a protrusion (120B)), or FIG. 76 (recessed grooves (120A) and (120C) with a face-lock insert (137)). In the either case, the selection of one through-hole out of the three possibilities ((130), (131), or (132) in FIG. 74) can be achieved by selecting the corresponding v-groove among the three possible sets, namely (133), (134), or (135). The resulting alignments are shown in FIGS. 77 and 78 as two possible examples .

0 FIG. 75 shows a matched pair of an alignment groove (120A) and an alignment ridge (120B). Each of the embodiments (123 A) and (123B) represent the face-lock surface shown in FIG. 59, 61, or 74. As indicated, the alignment ridge (120B) may be fabricated by etching V-grooves on the both sides of the ridge (120B) on the silicon surface FIG. 76 shows two recessed alignment grooves (120A) and (120C) and a cylindrical face-lock insert (137) in-between that facilitates the face-locking.
FIG. 77 shows a matched pair of the three alignment grooves as shown in FIG. 74, (133A) through (135A), and (133B) through (135B). Each set of these grooves are supposed to belong to a face-locking surface as shown in FIG. 74. By selecting the grooves to lock via a face-lock insert (137), one may lock the two surfaces either as shown in FIG. 77 or FIG. 78. In turn, this will determine which through-holes are being used among the three choices, (130) through (132), in FIG. 74.

FIG. 79 shows that the face-lock embodiment of the present invention can be extended to align other optical components such as a light source (138) and a lens (139). It shows a modular approach, in which a number of face-lock embodiments (123), (140), (141), and (142) are prepared separately and assembled together using the self-alignment mechanism of the face-lock features (120A) and (124B ), and the counterparts in the rest of AIUIENOED S"L' r u~ Y ~

the stack. Photolithography ensures that the optical axis is at the center within one-micron tolerance. The pre-determined thickness of the individual face-lock embodiments (123), (140), (141), and (142) ensures that the distances between the optical components, (128), (139), (138), are accurate. FIG. 80 shows that a light (143) is emerging from the light source (138) to be focused by the lens (139) into the fiber core (144). The light source (138) may be a light emitting diode (LED) or surface emitting laser diode (that are energized by a voltage V as shown in FIG. 80), or a light delivered 0 to the spot (138) by a set of reflectors or/and deflectors. Micro-machined silicon and other crystal (GaAs or InP) wafers would preferred materials for such modular face-lock embodiments, since, as described above in detail, the registration of the face-lock features and through-holes can be fabricated with better than one-micron accuracy on these wafers using the standard integrated circuit lithography technology.

Even though the face-lock surface contours (120A), (120B) and the likes reside on the surfaces that are mutually parallel in FIG.
79, they may be, by a simple extension, provided on other planes, such as the one perpendicular to the face-lock surfaces shown in FIG. 79.

(FIGS. 62, 63, 68, 69, 70, 71, 72, 73, 74, 79 and 80 contain an important and distinct teaching that a through-hole may be tailor-fabricated with better than one or two micron accuracy to terminate and align an optical fiber, or other optical components such as a lens, on a wafer with a preferential etching characteristics. FIGS. 73 and 74 also teach a method how to prepare a set of through-holes with incrementally varying hole dimensions. Even though these embodiments and teachings are described in this invention, they are not part of the face-lock mechanism or features, which are the main subject of the present invention. Accordingly these embodiments and teachings related to the through-holes will be prepared separately as a divisional patent application of the present (parent) patent application.) AMENDEC ~t:'-ET

5 ~PEA~; 15FEB1996 It would be almost impossible to describe all the possible variations that utilizes the basic teaching of the present invention.
Accordingly, it would be useful to conclude the detailed description by clarifying again the essence of the teaching of this invention using an optical fiber and a lens. Referring to FIG. 81, a typical embodiment of the present invention comprises three elements: an optical fiber (145) with its end terminated, a first surface (146) residing on the plane coinciding with the end-facet of the optical fiber (145), and a second surface (147), containing a 0 lens (148), to be mated with the first surface (146). The first surface (146) has an unique contour on it, while the second surface (147) have another unique contour that may be locked with that of the first surface (146) in a stable position when brought together.

The concept of choosing among the multiple grooves (133), (134), and (137) in FIG. 74 through 77 may be slightly modified to realize an optical switching embodiment. A number of optical components (through-holes (168) through (173) for accommodating optical fibers (174) through (179) in this example), and a number of V-grooves (180) through (186) for face-lock positioning are fabricated on one connector part (187) as shown in FIG. 82. Side and front sectional views along the various axes indicated are shown. The other connector part (188), schematically illustrated in FIG. 83 using heavy lines, shows an optical component (a through-hole (189) fo~ a fi~er (190) in this example) and v-grooves (191), (192), and (193). FIG. 84 shows one possible mating position between the two connector parts (187) and (188), whereby the fiber (190) is aligned to the fiber (177). FIG. 85 shows another possible mating position, in which the fiber (190) is aligned to the fiber (174). FIG. 86 shows yet another possible mating position, in which the fiber (190) is connected to the fiber (175). In this way, one can select different mating positions among periodically-located face-lock features, accomplishing an optical switching from one fiber to another. A

- AMENDED S~EEr PCTIUS 95 / 0'9 296 6 IPE~US 15FEB1996 mechanical fiber optic switch can be manufactured by mechanizing the switching described herein.

The face-lock V-grooves of FIG. 82 and 83 may be replaced by sets of V-squares (194) and (195), as shown in FIG. 87, and by sets of V-squares (203) and (204), as shown in FIG. 88. Matching the fiber (202) to one of the fibers among (196) through (201) can be accomplished in the same fashion, as depicted in FIGS. 89 through 90.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

AME~ID~D SHEET

Claims

1. An optical interconnection means comprising;
a first optical component;
a first face-locking surface;
a second optical component;
and a second face-locking surface;

wherein the first face-locking surface and the second face-locking surface are substantially planar, and the first optical component is located on the first face-locking surface, and the first face-locking surface has a first type of surface feature, and the first type of surface feature has an unique positional relationship with respect to the first optical component; and the second optical component is located on the second face-locking surface, and the second face-locking surface has the second type of surface feature that matches to the first type of feature so as to be locked in position to the first type of surface feature when pressed against the first face-locking surface in a face-to-face fashion, and the second type of surface feature has the same unique positional relationship with respect to the second optical component; whereas precise optical alignment between the first optical component and the second optical component is achieved through the face-locking of the two surface features and their unique positional relationship with respect to the first and the second optical components.

2. The invention according to claim 1 wherein the axis of light is substantially perpendicular to the first face-locking surface.

3. The invention according to claim 1 wherein the first optical component is a lens.

4. The invention according to claim 1 wherein the first optical component is a light source.

5. The invention according to claim 4 wherein the light source is a surface-emitting laser diode.

6. The invention according to claim 1 wherein the first optical component is a light detector.

7. The invention according to claim 1 wherein the first optical component is an optical fiber.

8. The invention according to claim 1 wherein the first optical component comprises an array of optical fibers.

9. The invention according to claim 7 wherein the first face-locking surface contains through-hole for the optical fiber, and the optical fibers are positioned in the through-hole in an orientation largely perpendicular to the first face-locking surface.

10. The invention according to claim 1 wherein the first and the second face-locking surface features are registered by a lithographic procedure.

11. The invention according to claim 1 wherein the first face-locking surface is made of a semiconductor wafer.

12. The invention according to claim 11 wherein the semiconductor wafer is made of silicon.

13. The invention according to claim 11 wherein the semiconductor wafer contains light sources in the same plane where the surface feature resides.

14. The invention according to claim 11 wherein the semiconductor wafer contains light detectors in the same plane where the surface feature resides.

15. The invention according to claim 11 wherein the wafer is (100) type so that micromachined V-grooves and V-ridges constitute the face-locking surface features.

16. The invention according to claim 15 wherein the dimension of the V-grooves are chosen in such a way that an elongated object may be laid along the V-groove to aid the face-locking.

17. The invention according to claim 11 wherein the wafer is (100) type so that micromachined V-squares form the face-locking surface feature.

18. The invention according to claim 7 wherein the first face-locking surface contains a plurality of through-holes for the optical fiber, and the through-holes have slightly varying sizes to choose from for tight fitting with the optical fiber.

19. The invention according to claim 9 wherein the optical fiber is tapered in its diameter so that the optical fiber makes a tight fit with the through-hole at a certain position on the tapered section.

20. The invention as claimed in 1 wherein the face-locking surface features of the first face-locking surface and the second-face-locking surface have mutually-matched periodic patterns so that the first face-locking surface and the second-face-locking surface can be face-locked at many different positions, thus realizing an optical switching capability.

21. The invention as claimed in 20 wherein the matched periodic patterns comprise a set of V-grooves.

22. The invention as claimed in 20 wherein the matched periodic patterns comprise a set of V-squares.

23. The invention as claimed in 20 wherein the matched periodic patterns form an one-dimensional array.

24. The invention as claimed in 20 wherein the matched periodic patterns form a two-dimensional array.

25. The invention as claimed in 20 wherein there is a through-hole for an optical fiber in each period of the matched periodic patterns, so as to realize optical fiber switching capability.

26. The invention as claimed in 20 wherein the switching from one mating position to another is performed on command by a mechanized means so as to realize a mechanical optical switch.

27. The invention as claimed in 1 wherein the face-locking surface features are created by a molding technique.

28. An arrayed optical interconnection means comprising;
an array of a first optical component;
a first face-locking surface;
an array of a second optical component;
and a second face-locking surface;
wherein the first face-locking surface and the second face-locking surface are substantially planar, the array of the first optical component is located on the first face-locking surface, and the first face-locking surface has a first type of surface feature, and the first type of surface feature has an unique positional relationship with respect to the array of the first optical component; and the array of the second optical component is located on the second face-locking surface, and the second face-locking surface has the second type of surface feature that matches to the first type of feature so as to be locked in position to the first type of surface feature when pressed against the first face-locking surface in a face-to-face fashion, and the second type of surface feature has the same unique positional relationship with respect to the array of the second optical component;
whereas precise optical alignment between the array of the first optical component and the array of the second optical component is achieved through the face-locking of the two surface features and their unique positional relationship with respect to the array of the first and the second optical components.