Optical unit with increased reliability

[0002] 1. Field of the Invention

[0003] The present invention generally relates to optical units, and more particularly to an optical unit including photoelectric conversion modules and adapters for optical connectors.

[0004] An optical unit, after being inserted into and mounted in a shelf, is used with its optical connector adapters being connected with optical connectors provided to the ends of optical fiber cables that are external lines.

[0005] With an improvement in the performance of a semiconductor device included in the optical unit, an information processing rate per one optical unit has become higher and higher. For instance, the conventional rate of 1.2 Gbps is now doubled to 2.4 Gbps.

[0006] As the information processing rate of the optical unit increases, the number of channels that a single optical unit can handle also increases. Accordingly, the optical unit is allowed to increase the number of optical connectors connected to its optical connector adapters by increasing the number thereof.

[0007] 2. Description of the Related Art

[0008] FIGS. 1A and 1B are diagrams showing a conventional optical unit 10. The optical unit 10 is of a single channel. The optical unit 10 includes optical connector adapters 11 and 12 on the front side (Y₂side in FIGS. 1A and 1B), photoelectric modules 13 and 14, a semiconductor device 15 for signal processing, and optical fibers 16 and 17 in the middle, and connectors 18 on the rear side (Y₁side in FIGS. 1A and 1B). The optical fibers 16 and 17 each have one end fixed to the photoelectric modules 13 and 14, respectively, with the middle parts being engaged with a reel. Optical connectors 20 and 21 provided to the other ends of the optical fibers 16 and 17 are inserted into the upper connection holes of the optical connector adapters 11 and 12, respectively, so as to be connected to the optical connector adapters 11 and 12.

[0009] The optical unit 10 is inserted and plugged into a shelf 30 with the connectors 18 being connected with connectors 32 provided on a back wiring board 31.

[0010] Optical connectors 42 and 43 provided to ends of optical fiber cables 40 and 41 that are external lines are inserted into the lower connection holes of the optical connector adapters 11 and 12, respectively, so as to be connected with optical connector adapters 11 and 12. Thereby, the optical fibers 16 and 17 are connected with the optical fiber cables 40 and 41, respectively.

[0011] The optical connector adapters 11 and 12 are attached to a lower part of an arm-like adapter attachment member 51 whose upper part is supported by a shaft 50.

[0012] Normally, the adapter attachment member 51 is at a vertical position as shown in FIG. 1A with the optical connector adapters 11 and 12 and the adapter attachment member 51 being accommodated in a narrow space 53 formed in the optical unit 10 on its front side.

[0013] When the optical connectors 42 and 43 provided to the ends of the optical fiber cables 40 and 41 are connected with or pulled out from the optical connector adapters 11 and 12, first, as shown in FIG. 1B, an operator pulls and turns the adapter attachment member 51 toward herself/himself (in the Y₂direction) with her/his fingers, and pulls the optical connector adapters 11 and 12 out of the space 53. Then, with the adapter attachment member 51 in this state, the operator performs connection or extraction of the optical fiber cables 40 and 41.

[0014] Since the two adapters 11 and 12 are pulled out together from the optical unit 10, a clearance a between the adapters 11 and 12 remains narrow outside the optical unit 10.

[0015] Therefore, even if levers for locking the optical connectors 42 and 43 to the adapters 11 and 12 were provided, it would be difficult to operate the levers. Accordingly, the optical connectors 42 and 43 are inserted into the adapters 11 and 12 so tight as to maintain connection by frictional force. Hence, if a strong pulling force is applied to the optical connectors 42 and 43, the optical connectors 42 and 43 may be pulled out from the adapters 11 and 12, thus questioning the reliability of the connection of the optical connectors 42 and 43 with the adapters 11 and 12.

[0016] In order to provide a lock mechanism, the clearance a between the adapters 11 and 12 is required to increase so that a finger of the operator may be allowed therein. This requires the space 53 to be considerably widened along the Y₁-Y₂axis, thus causing the problem of increasing the optical unit 10 in size along the Y₁-Y₂axis instead of downsizing the optical unit 10.

[0017] This problem is highlighted when the number of optical connector adapters is increased. Therefore, practically, it is not feasible to widen a clearance between adjacent optical connector adapters when the number of channels handled by a single optical unit is increased due to improvement in the information processing rate of a semiconductor device.

[0018] Accordingly, it is a general object of the present invention to provide an optical unit in which the above-described disadvantages are eliminated.

[0019] A more specific object of the present invention is to provide an optical unit whose reliability is increased without an increase in size.

[0020] The above objects of the present invention are achieved by an optical unit including photoelectric conversion modules, a plurality of adapter support members whose upper parts are rotatably supported, and a plurality of optical connector adapters attached to lower ends of the adapter support members so as to be arranged next to each other, the optical connector adapters being contained in the optical unit, wherein the adapter support members are rotated separately so that the optical connector adapters are extracted outside from the optical unit with a space formed between each adjacent two of the optical connector adapters, each of the optical connector adapters has insertion holes formed on each of first and second opposing sides thereof, optical connectors provided to ends of optical fibers extending from the photoelectric conversion modules are connected to the insertion holes formed on the first sides of the optical connector adapters, and optical connectors provided to ends of external optical fibers are connected to the insertion holes formed on the second sides of the optical connector adapters.

[0021] According to the above-described optical unit, the adapter support members are rotated independently so that the space, into which a finger is inserted for performing a connection operation, is formed between each adjacent two of the optical connector adapters. Accordingly, the optical unit permits usage of an optical connector with a lock lever, thus increasing the reliability of optical connector connections.

[0022] Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:

[0023] FIGS. 1A and 1B are diagrams showing a conventional optical unit;

[0024] FIG. 2 is a perspective view of an optical unit according to an embodiment of the present invention;

[0025] FIG. 3 is an exploded perspective view of an communication apparatus formed by the optical unit of FIG. 2;

[0026] FIGS. 4A and 4B are diagrams showing an optical connector adapter assembly of the optical unit of FIG. 2;

[0027] FIG. 5 is a diagram showing the optical connector adapter assembly of FIGS. 4A and 4B attached to the optical unit of FIG. 2;

[0028] FIG. 6 is an exploded perspective view of the optical connector adapter assembly according to the present invention;

[0029] FIG. 7 is a diagram for illustrating a mechanism supporting the optical connector adapter assembly according to the present invention;

[0030] FIG. 8 is another diagram for illustrating the supporting mechanism of FIG. 7;

[0031] FIGS. 9A and 9B are a front view and a side view, respectively, of a first adapter support member of the optical connector adapter assembly according to the present invention;

[0032] FIGS. 10A and 10B are a front view and a side view, respectively, of a second adapter support member of the optical connector adapter assembly according to the present invention;

[0033] FIGS. 11A and 11B are a front view and a side view, respectively, of a third adapter support member of the optical connector adapter assembly according to the present invention;

[0034] FIGS. 12A and 12B are a front view and a side view, respectively, of a fourth adapter support member of the optical connector adapter assembly according to the present invention;

[0035] FIG. 13 is a diagram showing an optical connector adapter of the optical unit of FIG. 2 and corresponding optical connectors according to the present invention;

[0036] FIGS. 14A through 14C are a top view, a side view, and a rear view, respectively, of the optical connector adapter of FIG. 13;

[0037] FIGS. 15A and 15B are a top view and a side view, respectively, of any of the optical connectors of FIG. 13;

[0038] FIGS. 16A through 16C are diagrams showing states of operation of the optical connector adapter assembly according to the present invention; and

[0039] FIG. 17 is a diagram for illustrating optical connector connection and disconnection operations according to the present invention.

[0040] A description will now be given, with reference to the accompanying drawings, of an embodiment of the present invention.

[0041] In the following drawings, the Y₁-Y₂axis represents a rear-front dimension.

[0042] FIG. 2 is a diagram showing an optical unit 60 according to the embodiment of the present invention. The optical unit 60 is inserted upright into a shelf 61 as shown in FIG. 3 and plugged thereinto with connectors 62 being connected with connectors 64 provided to a back wiring board 63, thereby forming a communication apparatus 65.

[0043] The optical unit 60 is of a four-channel type and includes a front member 70, a printed board 71 whose Y₂side is fixed to the front member 70, and a case 72 surrounding the printed board 71.

[0044] Card levers 73 and 74 are attached to the front member 70. The front member 70 is substantially shaped like a box with a space 75 having an opening on the Y₂side being formed between X₁-side and X₂-side walls 77 and 78. An optical connector adapter assembly 76 that forms the essential part of the present invention is provided in the space 75.

[0045] Photoelectric conversion modules 80 and 81 for the first channel, photoelectric conversion modules 82 and 83 for the second channel, photoelectric conversion modules 84 and 85 for the third channel, photoelectric conversion modules 86 and 87 for the fourth channel, and a semiconductor device 88 are mounted on the printed board 71.

[0046] Optical fibers 190 through 197 extending from the photoelectric conversion modules 80 through 87, respectively, are properly engaged with a reel 98, and extend therefrom into the space 75 of the front member 70 to be connected with the adapter assembly 76.

[0047] Next, a description will be given of the optical connector adapter assembly 76.

[0048] As shown in FIGS. 4A through 7, the adapter assembly 76 includes first through fourth adapter support members 91 through 94 that are combined so that the second through fourth adapter support members 92 through 94 are positioned inside the first through third adapter support members 91 through 93, respectively. The first through fourth adapter support members 91 through 94 are joined by flanged shaft members 95 and 96 and E washers 97 and 98. Optical connector adapters 101 through 104 are attached to the adapter support members 91 through 94, respectively. The adapter assembly 76 is attached to the front member 70 with bolt members 110 and 111 being fitted to the flanged shaft members 95 and 96, respectively. Each of the adapter support members 91 through 94 is a sheet metal member formed by bending and properly spot-welding sheet metal members of a thickness t1 (shown in FIG. 9A) stamped out by a press to have given shapes.

[0049] As shown in FIGS. 6, 9A, and 9B, the first adapter support member 91 includes two opposing arm parts 91aand 91bcranked (formed) in the Y₂direction and an adapter attachment part 91cof a square-frame shape formed on the lower ends of the arm parts 91aand 91b.

[0050] As shown in FIGS. 6, 10A, and 10B, the second adapter support member 92 includes two opposing arm parts 92aand 92bcranked in the Y₂direction and an adapter attachment part 92cof a square-frame shape formed on the lower ends of the arm parts 92aand 92b.

[0051] As shown in FIGS. 6, 11A, and 11B, the third adapter support member 93 includes two opposing linear arm parts 93aand 93band an adapter attachment part 93cof a square-frame shape formed on the lower ends of the arm parts 93aand 93b.

[0052] As shown in FIGS. 6, 12A, and 12B, the fourth adapter support member 94 includes two opposing arm parts 94aand 94bcranked in the Y₁direction and an adapter attachment part 94cformed on the lower ends of the arm parts 94aand 94b. The adapter attachment part 94chas a shape obtained by cutting a square frame in halves.

[0053] The arm parts 91athrough 94aand 91bthrough 94bof the adapter support members 91 through 94 include step parts 91dthrough 94dand 91ethrough 94e, respectively. The step parts 91dthrough 94dand the step parts 91ethrough 94eare provided in symmetry along the X₁-X₂axis, or in the X₁-X₂directions. The step parts 91dthrough 94dhave respective step sizes A1 through A4 determined to satisfy A1<A2<A3<A4 with a difference of the thickness t1 of each of the arm parts 91dthrough 94dbeing provided between A1 and A2, A2 and A3, and A3 and A4. The step parts 91ethrough 94ealso have the same step sizes A1 through A4, respectively. Thereby, the arm parts 92aand 92bare positioned inside the arm parts 91aand 91b, the arm parts 93aand 93bare positioned inside the arm parts 92aand 92b, and the arm parts 94aand 94bare positioned inside the arm parts 93aand 93bso that the arm parts 91athrough 94aoverlap one another and the arm parts 91bthrough 94boverlap one another. The step size A1 of the step part 91dis equal to a thickness t2 of a later-described flange part 95b.

[0054] As shown in FIGS. 7 and 8, the arm parts 91athrough 94aare supported by the flanged shaft member 95 and the E washer 97. As shown in FIG. 8, the flanged shaft member 95 includes a shaft part 95a, the flange part 95bformed on a longitudinal end (the X₁end in FIG. 7) of the shaft part 95a, a groove 95cformed in a vertical end (the Z₁end in FIG. 7) of the shaft part 95a, a female screw part 95dpenetrating the shaft part 95a, and a plane part 95eformed by cutting off part of the other vertical end (the Z₂end in FIG. 7) of the shaft part 95a. The shaft part 95apenetrates holes 91fthrough 94fwith the E washer 97 being fitted and attached to the groove 95c. Accordingly, the arm parts 91athrough 94aare supported by the shaft part 95abetween the flange part 95band the E washer 97.

[0055] Just as the arm parts 91athrough 94a, the arm parts 91bthrough 94bhave respective holes 91gthrough 94gsupported by the flanged shaft member 96 and the E washer 98. The flanged shaft member 96 has the same shape as the flanged shaft member 95, and includes a shaft part 96a, a flange part 96b, a groove 96c, a female screw part 96d, and a plane part 96e.

[0056] The holes 91fthrough 93fand the holes 91gthrough 93gare circular so that each of the first through third adapter support members 91 through 93 is independently rotatable with respect to the flanged shaft members 95 and 96. On the other hand, the holes 94fand 94gof are shaped like a truncated circle, or a circle whose lower part is filled in as shown in FIGS. 8 and 12B. The holes 94fand 94ghave respective chord parts 94f₁and 94g₁. The chord parts 94f₁and 94g₁contact the plane parts 95eand 96eof the shaft parts 95aand 96aso that the fourth adapter support member 94 is restrained from rotating between the flanged shaft members 95 and 96.

[0057] A stopper 91his formed on the upper end of the arm part 91aof the first adapter support member 91. Engaging strips 91iand 91jare formed by bending parts of the Y₁ends of the arm parts 91aand 91binwardly toward each other, that is, in the X₂and X₁directions, respectively. The arm parts 94aand 94bof the fourth adapter support member 94 are connected by a beam part 94h.

[0058] The adapter attachment parts 91cthrough 94cof the first through fourth adapter support members 91 through 94 have sizes so that the optical connector adapters 101 through 104 are fitted thereto, respectively, and are equal in X₁-X₂dimensions. The adapter attachment parts 91cthrough 93care also equal in Y₁-Y₂dimensions. Since the arm parts 91athrough 94aoverlap one another and the arm parts 91bthrough 94boverlap one another, the adapter attachment parts 91cthrough 94cof the first through fourth adapter support members 91cthrough 94care arranged closely along the Y₁-Y₂axis or in the Y₁-Y₂directions as shown in FIG. 4B.

[0059] The adapter attachment part 91cincludes engaging strips 91c₁and 91c₂formed by bending the lower ends of the X₁and X₂sides of the adapter attachment part 91cin the X₂and X₁directions, respectively. The adapter attachment parts 92cand 93chave the same structure as the adapter attachment part 91c. That is, the adapter attachment part 92cincludes engaging strips 92c₁and 92c₂and the adapter attachment part 93cincludes engaging strips 93c₁and 93c₂.

[0060] The Y₁-side adapter attachment part 94cincludes engaging strips 94c₁and 94c₂formed by bending the lower ends of the X₁and X₂sides of the adapter attachment part 91cinwardly toward each other, that is, in the X₂and X₁directions, respectively. The adapter attachment part 94cfurther includes engaging strips 94c₃and 94c₄formed to extend in the Z₂direction from the X₁and X₂ends of the lower end of the Y₁side of the adapter attachment part 94c, respectively.

[0061] A tag 99 is attached to the Y₂-side adapter attachment part 91cfor protecting the eyes of an operator from a laser beam.

[0062] Next, a description will be given, with reference to FIGS. 13 through 15B, of the optical connector adapter 101 and an optical connector 140.

[0063] The optical connector adapter 101 is an LC adapter and includes a housing 120 of a rectangular parallelepiped shape and a U-shaped leaf spring member 130 fitted to the outside of the housing 120.

[0064] The housing 120 has optical connector insertion holes 121 and 122 formed therein from the Z₂side and optical connector insertion holes 123 and 124 formed therein from the Z₁side. The optical connector insertion holes 121 and 122 are arranged side by side in the X₁-X₂directions, and the optical connector insertion holes 123 and 124 are arranged side by side in the X₁-X₂directions. Further, the optical connector insertion holes 121 and 123 are aligned along the Z₁-Z₂axis or in the Z₁-Z₂directions, and the optical connector insertion holes 122 and 124 are aligned in the Z₁-Z₂directions. Split sleeves 127 are provided in the center part of the housing 120.

[0065] The optical connector insertion holes 121 through 124 have respective engaging parts 121athrough 124a.

[0066] Ribs 125 and 126 are provided in the center parts of the X₁-side surface and the X₂-side surface of the housing 120, respectively.

[0067] The U-shaped leaf spring member 130 is provided above the ribs 125 and 126, that is, on the Z₁side therefrom, on the housing 120. The U-shaped leaf spring member 130 includes plates 131 and 132 protruding obliquely from the X₁and X₂sides thereof, respectively.

[0068] The other optical connector adapters 102, 103, and 104 have the same configuration as the optical connector adapter 101.

[0069] As shown in FIG. 6, the optical connector adapter 101 is attached to the adapter attachment part 91cof the first adapter support member 91 by being inserted thereinto from the bottom, or the Z₂side. The plates 131 and 132 are pressed flat in entering the adapter attachment part 91cand spread again inside the adapter attachment part 91c. As shown enlarged in FIG. 4A, the optical connector adapter 101 is attached to the adapter attachment part 91cwith the engaging strips 91c₁and 91c₂being sandwiched between the plate 131 and the rib 125 and between the plate 132 and the rib 126, respectively.

[0070] The optical connector adapters 102 and 103 are attached to the adapter attachment parts 92cand 93c, respectively, in the same manner as the optical connector adapter 101 is attached to the adapter attachment parts 91c.

[0071] As shown enlarged in FIG. 4B, the optical connector adapter 104 is attached to the adapter attachment part 94cwith the engaging strips 94c₁and 94c₂being sandwiched between the plate 131 and the rib 125 and between the plate 132 and the rib 126, respectively, and the Y₁ends of the ribs 125 and 126 being engaged with and held by the engaging strips 94c₃and 94c₄, respectively.

[0072] The optical connector adapter assembly 76 has the above-described configuration. Since the adapter support members 91 through 94 are attached to the front member 70 as a single unit of the optical connector adapter assembly 76, the optical unit 60 may be assembled more easily than an optical unit in which adapter support members are attached thereto one by one.

[0073] Each of the optical connectors 140, which is an LC connector as shown in FIGS. 13, 15A, and 15B, is connected to an end of an optical fiber cable 160 as shown in FIG. 3. Each optical connector 140 includes a main body 141 of a synthetic resin. A ferrule 142 is provided to the tip of the main body 141 so as to protrude therefrom. A coil spring 143 for pushing the ferrule 142 forward is incorporated in the main body 141. Each optical connector further includes a lock lever 144 formed integrally with the main body 141.

[0074] As shown in FIGS. 2, 5, and 7, the optical connector adapter assembly 76 is attached to the front member 70 in the space 75 with the bolt member 110 being screwed into the female screw part 95dof the shaft member 95 through a circular hole 77aof the wall 77 from the X₁side of the front member 70 and the bolt member 111 being screwed into the female screw part 96dof the shaft member 96 through a circular hole 78aof the wall 78 from the X₂side of the front member 70.

[0075] When the operator screws the bolt member 110 and 111 into the female screw parts 95dand 96d, the shaft members 95 and 96 are prevented from rotating. Therefore, the operator is not required to hold the shaft members 95 and 96 by fingertips to prevent idle rotation of the shaft members 95 and 96. Accordingly, the bolt members 110 and 111 are tightened with ease.

[0076] The bolt members 110 and 111 include respective cylindrical head parts 110aand 111a. Hexagonal holes 110band 111bfor screwing are formed on end surfaces (that is, the X₁and X₂end surfaces in FIG. 7) of the head parts 110aand 111a, respectively. The head parts 110aand 111aare fitted rotatably into the circular holes 77aand 78a, respectively.

[0077] Next, a description will be given of how the optical connector adapter assembly 76 operates.

[0078] Before operation, the adapter assembly 76 is in a pendent state, being supported by the bolt members 110 and 111 in the circular holes 77aand 78aof the walls 77 and 78 as shown in FIGS. 2, 4A, 4B, and 5. In this state, the adapters 101 through 104 are housed in the space 75, being arranged closely side by side in the Y₁-Y₂directions.

[0079] The Y₁ends of the arm parts 92athrough 94aof the adapter support members 92 through 94 are aligned and the Y₁ends of the arm parts 92bthrough 94bof the adapter support members 92 through 94 are aligned. The engaging strips 91iand 91jare positioned away from the Y₁ends of the arm parts 92aand 92bby a dimension (distance) B in the Y₁direction.

[0080] When the operator catches the first adapter support member 91 in the initial position on her/his finger and pulls the first adapter support member 91 in the Y₂direction, the first adapter support member 91 is rotated clockwise to be pulled out from the space 75 toward the Y₂direction.

[0081] As shown in FIG. 16A, the first adapter support member 91 is rotated up to a position where the stopper 91hcontacts a top plate part 79 defining the upper limit of the space 75. An angle of rotation (a rotation angle) α formed by this rotation between the initial and rotated positions is a maximum pull-out angle, which is approximately 45°. The first adapter support member 91 is designed so as not to rotate by more than the rotation angle α in order that a laser beam may not hurt the eyes of the operator.

[0082] While the first adapter support member 91 is rotated clockwise, at some point, the engaging strips 91iand 91jengage and hold the arm parts 92athrough 94aand 92bthrough 94bof the second through fourth adapter support members 92 through 94. Thereafter, following the first adapter support member 91, the second through fourth adapter support members 92 through 94 are rotated clockwise to be pulled out from the space 75 in the Y₂direction.

[0083] At this point, a space 200 exists between the adapter 101 attached to the first adapter support member 91 and the adapter 102 attached to the second adapter support member 92. A dimension C of the space 200 is determined by the dimension B so as to allow a finger 210 therein.

[0084] When the operator catches the second adapter support member 92 on her/his finger and pulls the second adapter support member 92 in the Y₂direction in the state shown in FIG. 16A, the second adapter support member 92 is independently rotated in the Y₂direction to enter a state shown in FIG. 16B, where a space 201 having the dimension C is formed between the adapters 102 and 103. At this point, since the second adapter support member 92 is positioned outside the space 75, the second adapter support member 92 is easily caught on the finger of the operator.

[0085] When the operator catches the third adapter support member 93 on her/his finger and pulls the third adapter support member 93 in the Y₂direction in the state shown in FIG. 16B, the third adapter support member 93 is independently rotated in the Y₂direction to enter a state shown in FIG. 16C, where a space 202 having the dimension C is formed between the adapters 103 and 104. At this point, since the lower part of the third adapter support member 93 is positioned outside the space 75, the lower part is easily caught on the finger of the operator.

[0086] When the operator catches the fourth adapter support member 94 on her/his finger and pulls the fourth adapter support member 94 in the Y₂direction in the state shown in FIG. 16C, the fourth adapter support member 94 is rotated in the Y₂direction to a position indicated by a double-dot chain line in FIG. 16C. At this time, the fourth adapter support member 94 is rotated together with the bolt members 110 and 111. Here, since the lower end of the fourth adapter support member 94 is positioned at the exit of the space 75, the lower end is easily caught on the finger of the operator.

[0087] When the operator takes the finger off the fourth adapter support member 94, the first through fourth adapter support members 91 through 94 are rotated counterclockwise by gravity to return to their original states shown in FIGS. 2, 4A, 4B, and 5.

[0088] Here, the second through fourth adapter support members 92 through 94 may be designed so as not to follow the first adapter support member 91. In such a configuration, with the first adapter support member 91 being in the pulled-out state, each of the second through fourth adapter support members 92 through 94 remains in a vertical state shown in FIG. 4B in the space 75. Therefore, it is difficult to catch the second adapter support member 92 on the finger and pulls the second adapter support member 92 out from the space 75. Since the third and fourth adapter support members 93 and 94 are positioned in the bottom, that is, on the Y₁side, of the space 75, the operator has more difficulty in making her/his finger touch the third and fourth adapter support members 93 and 94. Therefore, the configuration of this embodiment provides better operability that the configuration where the second through fourth adapter support members 92 through 94 are prevented from following the first adapter support member 91.

[0089] Next, a description will be given of an operation of connecting the optical connectors 140 to the optical connector adapter assembly 76.

[0090] The optical connector 140 provided to the tip of the optical fiber cable 150 that is an external line is connected to the adapter 102 in the following manner. First, the adapter assembly 76 is set in the state shown in FIG. 16B. Then, the finger 210 is inserted into the space 201 as shown in FIG. 17 so that the optical connector 140 is inserted into the adapter 102. An operation of releasing a lock by pressing the lock lever 144 at the time of pulling out the optical connector 140 from the adapter 102 is performed in the following manner. First, the adapter assembly 76 is set in the state shown in FIG. 16B. Then, the finger 210 is inserted into the space 201 as shown in FIG. 17 so that the lock lever 144 is pressed in the Y₂direction.

[0091] An operation of connecting the optical connector 140 to the adapter 101 and an operation of releasing a lock at the time of pulling out the optical connector 140 from the adapter 101 are performed by setting the adapter assembly 76 in the state shown in FIG. 16A and inserting the finger 210 into the space 200.

[0092] An operation of connecting the optical connector 140 to the adapter 103 and an operation of releasing a lock at the time of pulling out the optical connector 140 from the adapter 103 are performed by setting the adapter assembly 76 in the state shown in FIG. 16C and inserting the finger 210 into the space 202.

[0093] An operation of connecting the optical connector 140 to the adapter 104 and an operation of releasing a lock at the time of pulling out the optical connector 140 from the adapter 104 are performed by setting the adapter assembly 76 in the state where the fourth adapter support member 94 is in the position indicated by the double-dot chain line in FIG. 16C and inserting the finger 210 into a space formed on the Y₁side of the adapter 104.

[0094] An operation of connecting the optical connectors 140 provided to the tips of the optical fibers 90 through 97 extending from the case 72 into the front member 70 with the upper parts of the adapters 101 through 104 and an operation of pulling out the optical connectors 140 from the adapters 101 through 104 by pressing the lock levers 144 are performed by properly setting the optical connector adapter assembly 76 in the states shown in FIGS. 16A through 16C.

[0095] With the optical connector adapter assembly 76 being attached to the front member 70 as shown in FIG. 7, a space 220 is formed between the bolt members 110 and 111. Therefore, the optical fibers 90 through 97 are neither hindered by a shaft nor curved unnecessarily inside the front member 70. Further, the existence of the space 220 also facilitates connecting the optical connectors 140 provided to the tips of the optical fibers 90 through 97 with the upper parts of the adapters 101 through 104.

[0096] The present invention is not limited to the specifically disclosed embodiment, but variations and modifications may be made without departing from the scope of the present invention.

[0097] The present application is based on Japanese priority application No. 2001-272600 filed on Sep. 7, 2001, the entire contents of which are hereby incorporated by reference.