Abstract:
An improved disconnect structure for SFP optical transceiver modules uses a slide  21  that travels relative to the module housing over a limited range. The slide  21  has operating pieces  28  which are elastically displaceable to elastically displace a spring plate  18  of the cage in a direction to release the locked state. The slide initially moves relative to the module housing to deflect the spring plate downwardly and release the locked state. When the slide then reaches the end of its range of motion relative to the module housing, further withdrawal of the slide pulls the module housing along with it, removing the module form the cage.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a module connector structure, preferably but not necessarily in an optical module for performing optical communication, and in preferred embodiments more particularly relates to an SFP (Small Form Factor Pluggable) optical transceiver module whose housing is received within a cage of equipment to which the optical module is attached. The present invention also relates to a method for disconnecting such a module from a cage in which it is inserted. 
   2. Description of Related Art 
   Optical transceiver modules conventionally include a light emitting element and a light receiving element that perform photoelectric conversion to enable communication by optical fiber. Such optical transceiver modules include a housing designed to be detachably attached inside a cage mounted on a circuit board to which the module is connected. An electrical connector connected to the board is provided in the cage, so that a connecting terminal of the optical transceiver is constructed to be connected to the electric connector when the optical transceiver module is attached in the cage. The optical transceiver module thus constructed enables optical communication by converting an optical signal transmitted to and received from the optical fiber into an electric signal transmitted to and received from the board. 
   However, when the optical transceiver module is pulled out of the cage during operation of the optical transceiver module, there is not only the possibility that the communication is interrupted in progress, but also the possibility that the communication apparatus including the optical transceiver module is out of order. Therefore, the optical transceiver module needs to be reliably fixed to an inside of the cage at least during operation. 
   For example, in recent years, the standard of measure called MSA (Multi Source Agreement) of SFP (Small Form-factor Pluggable) transceivers is established to give compatibility to the optical transceivers provided by various companies, and the shapes and sizes of the SFP transceivers and the cages to which the SFP transceivers are attached are standardized. According to the MSA standard of the SFP, a protruding locking portion is provided at a bottom surface of an optical transceiver, and a cage is provided with a spring plate portion in which a locking recess (hole or depression) is formed in which the locking portion is locked. 
   Therefore, when the optical transceiver module is attached inside the cage, the locking portion of the optical transceiver module is locked in the locking hole of the cage, so that the optical transceiver module can be locked into the cage. On the other hand, it is necessary to release locking by detaching the locking portion from the locking hole of the spring plate portion by some means, when the optical transceiver module is removed from the cage. 
   As a conventional optical transceiver of this type, a construction including an ejector for releasing locking is disclosed in U.S. Pat. No. 6,434,015, the entirety of which is hereby expressly incorporated by reference. 
     FIG. 11  is a perspective view showing the conventional optical transceiver disclosed in U.S. Pat. No. 6,434,015 with its undersurface facing upward. 
   The conventional optical transceiver shown in  FIG. 11  has a body  101  with a locking portion  114  formed thereon, which houses a light emitting element and a light receiving element, and an ejector  170  for removing the locking portion  114  from a locking hole (not shown) of the spring plate portion of a cage. The ejector  170  is housed inside an ejector seat which is formed at a lower portion  111  of the body  101 , so that by pressing a pressing portion  179  provided at a rear end of the ejector  170 , a tip end portion of the ejector  170  can be protruded to a vicinity of the locking portion  114  from an inside of the ejector seat. The tip end portion of the ejector  170  is designed to release the locked state of the locking portion  114  and the locking hole by bending the spring plate portion if it is projected when the locking portion  114  of the optical transceiver is locked in the locking hole of the spring plate portion of the cage. 
   Accordingly, this optical transceiver can removed from the inside of the cage by pressing a pressing portion  179  of the ejector  170  in the direction of the arrow g in the drawing to protrude the tip end portion to the vicinity of the locking portion  114 , and releasing the locked state of the locking hole of the spring plate portion of the cage and the locking portion  114 . 
   However, since the SFP optical transceiver according to the MSA standard is constructed to be about 10 mm high, and about 14 mm wide, and the module itself is compact, the ejector  170  (see  FIG. 11 ) included in such an optical transceiver is a very small component. Therefore, the pressing portion  179  of the ejector  170  shown in  FIG. 11  calls for a pushing operation with a fingertip or a nail in some housings. However, in the state in which the optical transceiver is attached in the cage, there is hardly a gap between the board on which the cage is loaded and the undersurface of the optical transceiver, and therefore a fingertip sometimes cannot successfully reach the pressing portion  179  of the ejector  170 , thus causing the problem that the operation for releasing lock is difficult to perform. 
   The removing direction of the optical transceiver shown in  FIG. 11  from the cage is the direction of the arrow h in  FIG. 11 , and this direction is the opposite direction from the pushing direction (the direction of the arrow g) of the ejector  170 . Namely, in the conventional optical transceiver, the operating direction for releasing lock, and the operation direction for taking the optical transceiver from the cage are opposite to one another, and these operations have to be performed independently from each other. Therefore, the optical transceiver has the problem that the operation of releasing the lock to taking out the optical transceiver from the cage is troublesome. 
   SUMMARY OF THE INVENTION 
   Consequently, the present invention has its object to provide a module connector structure that provides improved disconnect operation when disconnecting the module from a cage or housing into which it had been received, and a method for disconnecting such a module from a cage or housing. 
   In order to attain the aforementioned object, a module connector structure according to a preferred embodiment of the present invention includes, in a module designed for insertion into a cage, a connector structure comprising a locking protrusion formed on a housing of the module, the locking protrusion being adapted to engage in a recess of a spring plate in the cage; a slide mounted on the housing and slidably movable relative to the housing over a limited range; the slide having surfaces cooperating with opposing surfaces on the cage to cause the spring plate to deflect downwardly so as to free the locking protrusion from the recess as the slide is moved relative to the housing in a direction of withdrawing the module from the cage; wherein the slide is connected to the housing such that when the slide reaches an end of its range of motion relative to the housing, a further withdrawing force exerted on the slide serves to move the slide and the housing conjointly, thereby to withdraw the module from the cage. 
   Another embodiment of the invention provides, in an optical module having a housing in which communicating structure for performing optical communication is contained, and in which the housing is provided with a locking portion which is locked in a locking hole of a spring plate portion provided at a cage side in which the housing is attached, lock releasing means having a slide member movably provided at the housing in parallel with an attaching and detaching direction of the housing with respect to the cage and a supporting shaft provided at the housing and movably supporting the slide member to release a locked state of the locking hole and the locking portion. The slide member has operating pieces provided to be elastically displaceable to elastically displace the spring plate portion in a direction to release the locked state, and a supporting shaft receiving hole, which is provided along a moving direction of the slide member, and through which the supporting shaft is inserted. The operating piece is provided with a protrusion at an opposing surface opposed to the housing, and the housing is provided with a protruding portion for elastically displacing the spring plate portion by the operating piece by being engaged with the protrusion. 
   In the optical module according to this embodiment of the invention, the protrusion of the operating piece is engaged with the protruding portion by operating the slide member to move, and the operating piece is elastically displaced by the protruding portion. The elastically displaced operating piece elastically displaces the spring plate portion in the direction to release the locked state of the locking hole and the locking portion. The moving range of the slide member is reliably restrained by the supporting shaft inserted into the supporting shaft receiving hole, and therefore the slide member is reliably prevented from falling from the housing when pulled out of the housing. Further, the slide member is reliably restrained in the moving range by the supporting shaft inserted into the supporting shaft receiving hole, whereby the engaged state and engagement released state of the protrusion of the operating piece and protruding portion of the housing are smoothly switched, and reliability of the operation for releasing the locked state of the locking portion and the locking hole by the operating piece is sufficiently ensured. Therefore, according to the optical module, the operation of releasing the locked state of the cage and the housing, and the operation of taking the optical module out of the cage are successively performed by operating the slide member to move with respect to the housing. 
   It is preferable that the operating piece of the slide member is provided with a movement restraining portion for restraining movement of the slide member by being engaged with the housing when the slide member is pulled out of the housing. Thereby, the movement restraining portion of the operating piece is engaged with the housing when the slide member is pulled out of the housing, whereby the slide member is further reliably prevented from falling from the housing. 
   An optical module according to another embodiment of the present invention includes, in an optical module having a housing in which communicating means for performing optical communication is contained, in which the housing is provided with a locking portion which is locked in a locking hole of a spring plate portion provided at a cage side in which the housing is attached, lock releasing means having a slide member movably provided at the housing in parallel with an attaching and detaching direction of the housing with respect to the cage to release a locked state of the locking hole and the locking portion. The slide member has operating pieces provided to be elastically displaceable to elastically displace the spring plate portion in a direction to release the locked state. The operating piece has a movement restraining portion for restraining movement of the slide member by being engaged with the housing when the slide member is pulled out of the housing, and a protrusion provided at an opposing surface opposed to the housing. The housing is provided with a protruding portion for elastically displacing the spring plate portion by the operating piece by being engaged with the protrusion. 
   In the optical module according to this embodiment of the present invention constructed as above, by operating the slide member to move, the protrusion of the operating piece is engaged with the protruding portion and the operating piece is elastically displaced by the protruding portion. The elastically displaced operating piece elastically displaces the spring plate portion in the direction to release the locked state of the locking hole and the locking portion. The movement restraining portion of the operating piece is engaged with the housing when the slide member is pulled out of the housing, whereby the slide member is reliably prevented from falling from the housing. 
   It is preferable that the optical module according to the present invention includes a lever rotatably provided at the slide member to operate the slide member to move, and that the slide member is provided with a lever restraining portion for restraining a rotational position of the lever. Thereby, the lever rotated with respect to the slide member is stopped at a predetermined position, and therefore operability when operating the slide member to move by the lever is enhanced. 
   It is preferable that the lever is provided with a locking portion which is locked at the housing in a state in which the locking portion abuts to the housing and the housing is provided with a locking groove in which the locking portion of the lever is locked. Thereby, the locking portion of the lever is locked in the locking groove of the housing when, for example, the lever is not used, whereby the lever is prevented from float with respect to the housing. 
   A method for releasing a locked state of a module and a cage according to preferred embodiments of the present invention, in which the housing is provided with a locking portion which is locked in a locking hole of a spring plate portion provided at a cage side in which the housing is attached, comprises actuating lock releasing means having a slide member movably provided at the housing in parallel with an attaching and detaching direction of the housing with respect to the cage and a supporting shaft provided at the housing and movably supporting the slide member to release a locked state of the locking hole and the locking portion. The method of the present invention preferably has the steps of moving the slide member by moving the supporting shaft along a supporting shaft receiving hole provided in a moving direction of the slide member, and 
   releasing the locked state by elastically displacing the spring plate portion by engaging a protrusion included by an operating piece provided at the slide member to be elastically displaceable and a protruding portion provided at the housing. 
   Another method for releasing a locked state of an optical module and a cage according to the present invention is a method for releasing a locked state of an optical module having a housing in which communicating means for performing optical communication is contained, in which the housing is provided with a locking portion which is locked in a locking hole of a spring plate portion provided at a cage side in which the housing is attached, and the cage in which the optical module is attached, the optical module includes lock releasing means having a slide member movably provided at the housing in parallel with an attaching and detaching direction of the housing with respect to the cage to release a locked state of the locking hole and the locking portion. The method of this embodiment of the present invention has the steps of releasing the locked state by elastically displacing the spring plate portion by engaging a protrusion included by an operating piece provided at the slide member to be elastically displaceable and a protruding portion provided at the housing, and 
   restraining a movement of the slide member by engaging the operating piece of the slide member with the housing when the slide member is pulled out of the housing. 
   As described above, according to preferred embodiments of the present invention, operability when releasing the locked state of the cage and the housing is enhanced, and the operation of releasing the locked state of the cage and the housing, and the operation of taking the optical module out of the cage can be performed with a simple operation. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention will now be explained in greater detail with reference to the accompanying drawings, in which: 
       FIGS. 1(   a ) and  1 ( b ) are perspective views showing a state of an operation of attaching and detaching an optical module of this embodiment to and from a cage from a bottom surface side, in which  FIG. 1(   a ) shows a state in which the optical module is attached to the cage, and  FIG. 1(   b ) shows a state in which the optical module is detached from the cage; 
       FIGS. 2(   a ), ( b ) and ( c ) are views showing the optical module, in which  FIG. 2(   a ) shows a plan view,  FIG. 2(   b ) shows a side view, and  FIG. 2(   c ) shows a bottom view, respectively; 
       FIGS. 3(   a ), ( b ) and ( c ) are views showing the housing  11 , in which  FIG. 3(   a ) shows a bottom view,  FIG. 3(   b ) shows a side view, and  FIG. 3(   c ) shows a sectional view taken along the A-A line in  FIG. 3(   a ); 
       FIGS. 4(   a ), ( b ) and ( c ) are views showing a slide member  21 , in which  FIG. 4(   a ) shows a plan view,  FIG. 4(   b ) shows a side view and  FIG. 4(   c ) shows a front view, respectively; 
       FIG. 5  is a perspective view showing an example of another slide member; 
       FIG. 6  is a side view showing an example of another lever; 
       FIG. 7  is a side view showing a state in which the optical module is attached inside a cage; 
       FIG. 8  is a side view showing a state in which the lever is operated to rotate; 
       FIG. 9  is a side view showing a state in which the locked state of the housing and the cage is released by the slide member; 
       FIG. 10  is a side view showing a state in which the optical module is pulled out of the cage; and 
       FIG. 11  is a perspective view showing a conventional optical module. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   As shown in  FIG. 1(   a ) and  FIG. 1(   b ), an optical module  1  of this embodiment is constructed to be attachable to and detachable from a cage  2  provided on a board (not shown) such as a mother board or the like included in a communication apparatus, for example. When the optical module  1  is attached into the cage  2  in a parallel posture, the optical module  1  is in a locked state where it is locked onto the cage  2 , and is connected to an electric connector (not shown) provided at the board side. 
   The optical module  1  contains various kinds of optical elements which are communication means for performing optical communication, and includes a housing  11  provided with a locking portion  17  which is locked at the cage  2 . The optical module  1  also includes a lock releasing mechanism  20  which is a lock releasing means for releasing a locked state of the locking portion  17  of the housing  11  and the cage  2 . 
   An LD (laser diode) as a light emitting element, a PD (photodiode) as a light receiving element, and an optical unit having an optical element such as a lens are provided inside the housing  11 , though not shown. The housing  11  is provided with a connecting terminal  13  which is connected to the electric connector at the board side as shown in  FIG. 2(C) , and an opening  14  for exposing the connecting terminal  13  is formed on a bottom surface at a rear end side, which is inserted into the cage  2  along the inside of the cage  2 . 
   In the housing  11 , an input side connecting port  15   a  and an output side connecting port  15   b  to which connectors (not shown) of an optical fiber cable are attachably and detachably connected are respectively formed to extend across a front end surface and a top surface, as shown in FIG.  2 ( a ). A connector of the input side optical fiber cable for inputting an optical signal into the optical module  1  from an outside is connected to the input side connecting port  15   a , and a connector of an output side optical fiber cable for outputting an optical signal to the outside from the optical module  1  is connected to the output side connecting port  15   b.    
   As shown in  FIG. 3(   a ) and  FIG. 3(   c ), a recessed portion  16  is provided on a bottom surface of the housing  11 , and on the bottom surface in this recessed portion  16 , a protruding triangular prism-shaped locking portion  17  is provided for locking onto the cage  2 . In this locking portion  17 , an inclined surface  17   a  of which protruded amount from the bottom surface in the recessed portion  16  gradually becomes large as the housing  11  is inserted into the cage  2  is formed at an entry end side which enters the cage  2 , as shown in  FIG. 3(   b ). 
   Meanwhile, a spring plate portion  18  on which the locking portion  17  of the housing  11  is locked is formed at the cage  2  to be elastically displaceable, as shown in  FIG. 1(   a ) and  FIG. 1(   b ). This spring plate portion  18  is provided with a triangular locking hole  19  into which the locking portion  17  is inserted. Accordingly, as the housing  11  is inserted into the cage  2 , the spring plate portion  18  is smoothly elastically displaced by the inclined surface  17   a  of the locking portion  17 , and when the housing  11  is attached to the cage  2 , the locking portion  17  is locked in the locking hole  19 . 
   The lock releasing mechanism  20  has a slide member  21  for releasing the locked state of the locking portion  17  at the side of the housing  11  and the spring plate portion  18  at the side of the cage  2 , a lever  22  for operating this slide member  21  to move in the direction of the arrow a and the direction of the arrow b in  FIG. 1 , and a supporting shaft  23  for supporting the slide member to be movable in the directions of the arrows a and b. 
   The slide member  21  is formed by, for example, a resin material such as PPS (polyphenylene sulfide), a metal material having elasticity or the like. The slide member  21  has a base end portion  26  to which the lever  22  is mounted, a slide portion  27  movably supported at the housing  11 , and a pair of operation pieces  28  for elastically displacing the spring plate portion  18 . 
   The base end portion  26  is perpendicular to the moving directions of the slide member  21 , which are the directions of the arrows a and b in  FIG. 1 , and is provided with a supporting hole  31  for rotatably supporting the lever  22  across a width direction (hereinafter, simply called a width direction) which is parallel with the bottom surface of the housing  11 . 
   The slide portion  27  is integrally provided at the base end portion  26  as shown in  FIG. 4(   b ), and is provided with a supporting shaft receiving hole  32  in a long hole shape into which the supporting shaft  23  is inserted movably in the directions of the arrows a and b as shown in  FIG. 2(   c ). The supporting shaft  23  is inserted into the supporting shaft receiving hole  32 , and both ends of the support shaft  23  are respectively supported at the shaft holes provided at the housing  11 . 
   As shown in  FIG. 2(   c ) and  FIG. 3(   a ), a guide groove  33  for guiding the slide portion  27  in the moving direction is provided at the bottom surface of the housing  11 , and the slide portion  27  is slid along both opposing side surfaces of the guide groove  33 , whereby the relative position of each of the operating pieces with respect to the housing  11  is positioned. The depth of the guide groove  33  is made approximately equal to the thickness of the slide portion  27 , so that the slide portion  27  is not protruded from the bottom surface of the housing  11 . 
   As shown in  FIG. 4(   a ), a base end of each of the operating pieces  28  is integrally formed at the slide portion  27  with a predetermined space into which the locking portion  17  is capable of entering being provided between the opposing operating pieces  28 , and each of the operating pieces  28  is constructed to be elastically displaceable in the thickness direction of the spring plate portion  18 . At a tip end of each of these operating pieces  28 , a protrusion  34  formed into an approximately trapezoidal shape for elastically displacing the spring plate portion  18  is provided on an opposing surface opposed to the bottom surface of the recessed portion  16  of the housing  11 . 
   Meanwhile, the housing  11  is provided with approximately trapezoidal protruding portions  35 , with which the protrusions of the respective operating pieces  28  of the slide member  21  are engaged, at the positions opposing to each other with the locking portion  17  therebetween on the bottom surface of the recessed portion  16  as shown in  FIG. 3(   a ) and  FIG. 3(   c ). 
   Each of the operating pieces  28  may be provided with a protrusion, which is made to abut to the spring plate portion  18 , on the opposing surface opposed to the spring plate portion  18  when it is necessary to perform fine tuning of the displacement amount when the spring plate portion  18  is elastically displaced or the like, for example, and it is possible to perform fine tuning of the displacement amount of the spring plate portion  18  in accordance with the protruding amount of the projection. 
   As shown in  FIG. 4(   a ) and  FIG. 4(   b ), a slipping-off preventing surface  37  being a movement restraining portion which is engaged with the housing  11  side when the slide member  21  is moved in the direction of the arrow b is formed on one side surface which is slide on the side surface of the guide groove  33 , at the tip end side of each of the operating pieces  28  of the slide member  21 . This slipping-off surface  37  is formed to be approximately perpendicular to the side surface of the operating piece  28 . 
   Meanwhile, as shown in  FIG. 3(   a ), a stopper surface  38  for restraining the movement of the slide member  21  is notched and formed at the positions adjacent to the guide groove  33 , at the housing  11 . This stopper surface  38  is formed to make an acute angle with respect to the side surface of the guide groove  33 . Accordingly, when the slide member  21  is operated to move in the direction of the arrow b with respect to the housing  11 , the slipping-off preventing surface  37  of each of the operating pieces  28  is favorably butted to the stopper surface  38 , whereby the movement of the slide member  21  is restrained and the slide member  21  is prevented from falling off the housing  11 . 
   Then, the slide member  21  movably supported at the housing  11  is constructed so that the operating pieces  28  are not protruded from the inside of the recessed portion  16 , and the operating pieces  28  do not slide in contact with the spring plate portion  18 , in the state in which the protrusions  34  of the operating pieces  28  are not engaged with the protruding portions  35 . 
   The lever  22  shown in  FIG. 1(   b ) and the like is formed into an approximately U-shape of, for example, a metal material such as stainless or a resin material such as PPS, and the shaft portions formed by folding both ends are inserted into the support hole  31  of the base end portion  26  of the slide member  21  shown in  FIG. 4(   a ) and the like, and is supported rotatably in the direction of the arrow c and the direction of the arrow d in  FIG. 1(   b ). 
   As shown in  FIG. 5 , the slide member  21  may be provided with lever restraining pieces  41  which are lever retraining portions for restraining the rotating position of the lever  22  at both sides in the width direction of the base end portion  26 . By them, the lever  22  abuts to the lever restraining pieces  41  when the lever  22  is rotated in the direction of the arrow d, and is held at a predetermined position by these lever restraining pieces  41 , and therefore the lever  22  can be prevented from being rotated more than necessary. 
   The lever  22  may be constructed to be capable of being housed in the housing  11 . As such a construction, a locking portion  43  which is locked on the housing  11  is formed at the lever  22  by folding a part of the lever  22 , and a locking groove  44  in which the locking portion  43  of the lever  22  is locked is provided on the top surface of the housing  11 , for example, as shown in  FIG. 6 . This prevents the lever  22  from floating with respect to the housing  11 , for example, when the lever is not used. 
   Though not shown, the lever  22  may be provided with a color-coded indication member in accordance with each specification, for example, for each transmission distance of the optical module  1  as necessary. 
   Concerning the optical module  1  constructed as above, an operation of releasing the locked state of the housing  11  and the cage  2  by the lock releasing mechanism  20  will be explained with reference to the drawings. 
   In the optical module  1 , the locking portion  17  and the locking hole  19  are in the locked state and the lever  22  is disposed along the peripheral surface of the housing  11  when the housing  11  is attached in the cage  2 , as shown in  FIG. 7 . At this time, each of the operating pieces  28  of the slide member  21  is moved to the position at which the protrusion  34  is spaced from the protruding portion  35 , and is in the posture approximately parallel with the bottom surface of the recessed portion  16 , and a gap is ensured between the operating pieces  28  and the spring plate portion  18 . 
   First, as shown in  FIG. 8 , the lever  22  disposed along the peripheral surface of the housing  11  is operated to rotate in the direction of the arrow d, whereby the lock releasing mechanism  20  is brought into the state in which the operation of pulling out the slide member  21  is easily possible. 
   Next, as shown in  FIG. 9 , the operation of gripping the lever  22  and pulling it out in the direction of the arrow b, whereby the slide member  21  is moved in the direction of the arrow b. As the slide member  21  is moved in the direction of the arrow b, the supporting shaft  23  is moved from one end side to the other end side along the inside of the supporting shaft receiving hole  32  of the slide portion  27 , and the protrusion  34  of the operating piece  28  is engaged with the protruding portion  35 . 
   With the movement in the direction of the arrow b, the protrusion  34  of the operating piece  28  slides along the protruding portion  35 , whereby the slide member  21  is elastically displaced with the base end of the operating piece  28  as the support point, and the operating piece  28  is gradually protruded from the inside of the recessed portion  16 . Each of the operating pieces  28  is elastically displaced in the direction to protrude from the inside of the recessed portion  16 , and thereby each of the operating pieces  28  elastically displaces the spring plate portion  18  in the direction to release the locked state of the locking portion  17  and the locking hole  19 . 
   In the slide member  21 , when the supporting shaft  23  is moved to the other end side of the supporting shaft receiving hole  32 , the protrusion  34  of the operating piece  28  is stopped in the vicinity of the peak at which the protrusion  34  has ridden over the peak of the protruding portion  35 , and thereby the locked state of the protrusion  34  and the protruding portion  35  is held. Therefore, the spring plate portion  18  is kept in the posture in which the locked state of the locking hole  19  and the locking portion  17  is released by the operating pieces  28 , and it becomes possible to pull the housing  11  out of the cage  2 . 
   In the engaged state in which the protrusion  34  of the operating piece  28  is engaged with the vicinity of the top of the protruding portion  35 , the position of the operating piece  28 , which is protruded from the inside of the recesses portion  16 , from the bottom surface of the recessed portion  16  is made approximately equal to the protruded amount of the locking portion  17  from the bottom surface of the recessed portion  16 , so that the locked state of the locking portion  17  and the locking hole  19  is released by elastically and smoothly deforming the spring plate portion  18  by minimum necessary amount. 
   Subsequently, as shown in  FIG. 10 , the slide member  21  is operated to move further in the direction of the arrow b via the lever  22 , and thereby the housing  11  is pulled out of the cage  2 . When the housing  11  is pulled out of the cage  2 , and the locking portion  17  is separated from the locking hole  19 , the spring plate portion  18  returns to the flat state by the elastic force. When the slide member  21  is moved in the direction of the arrow b, the supporting shaft  23  abuts to one end of the supporting shaft receiving hole  32 , and the slipping-off preventing surface  37  of the operating piece  28  is butted to the stopper surface  38  of the housing  11 , whereby the slide member  21  is reliably prevented from falling from the housing  11 . 
   According to the lock releasing mechanism  20 , in the slide member  21 , the slide portion  27  is slid and guided along both the opposed side surfaces of the guide groove  33  of the housing  11 , and thereby the relative position in the width direction of the protrusion  34  with respect to the protruding portion  35  is positioned. The moving range in the directions of the arrows a and b of the slide member  21  is reliably restrained by the supporting shaft  23  moving along the supporting shaft receiving hole  32  of the slide portion  27 , and the relative positions in the moving direction of the protrusion  34  of the operating piece  28  and the protruding portion  35  are reliably positioned. 
   Accordingly, with the movement in the directions of the arrows a and b of the slide member  21 , the locked state and the lock releasing state of the protrusion  34  of the operating piece  28  and the protruding portion  35  are smoothly switched, and reliability of the operation of releasing the locked state of the locking portion  17  and the locking hole  19  by the operating piece  28  is sufficiently ensured. 
   As described above, in the optical module  1 , by the operation of pulling out the slide member  21  from the housing  11  with the lever  22 , the locked state of the housing  11  and the cage  2  is easily and securely released, and the housing  11  can be easily removed from the inside of the cage  2 . Namely, according to the lock releasing mechanism  20 , the operation of releasing the locked state of the cage  2  and the housing  11  and the operation of taking the optical module  1  out of the cage  2  are successively performed. 
   On the other hand, when the optical module  1  is attached inside the cage  2 , the spring plate portion  18  at the side of the cage  2  is gradually deformed elastically by the inclined surface  17   a  of the locking portion  17  at the side of the housing  11 , as the housing  11  is inserted into the cage  2  and moved in the direction of the arrow a, and the locking portion  17  is locked in the locking hole  19 , whereby the housing  11  is attached inside the cage  2 . 
   As described above, by including the locking releasing mechanism  20  having the slide member  21 , the optical module  1  is enhanced in the operability on releasing the locked state of the cage  2  and the housing  11 , and the operation of releasing the locked state of the cage  2  and the housing  11  and the operation of taking the optical module  1  out of the cage  2  can be performed with the simple manipulation. 
   Since in the construction of the lock releasing mechanism  20 , the shape of the slide member  21  and the supporting structure for movably supporting the slide member  21  and the like are simplified as compared with the conventional construction, the production cost of the optical module  1  can be reduced and the productivity of the optical module  1  can be enhanced. 
   While the present invention has been described in connection with various preferred embodiments thereof, it is to be understood that those embodiments are provided merely to illustrate the invention, and should not be used as a pretext to limit the scope of protection conferred by the true scope and spirit of the appended claims.