Abstract:
An optical transceiver having a bi-directional optical subassembly (BOSA) and a twin optical port is disclosed. The BOSA is installed with respect to one of the twin port, and a plug is plugged within the other of the twin port. The plug, which is made of resin material, is rigidly set in the other of the twin port and reliably prohibited from slipping out from the port.

Description:
BACKGROUND 
     1. Field of the Invention 
     The present application relates to an optical transceiver, in particular, the application relates to an optical transceiver providing a pair of optical ports, one of which is covered with plug. 
     2. Background Arts 
     One type of optical transceiver is known in the field where the optical transceiver provides a bi-directional optical sub-assembly (BOSA) and a pair of optical ports, only one of which is coupled with the BOSA and the other ports are sealed to prevent an external optical connector from mating therewith. The present application proposes one type of a component to seal the port uncoupled with the BOSA. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention relates to an optical transceiver, which comprises an optical receptacle having a pair of ports, a bi-directional optical sub-assembly (BOSA) set in one of the paired ports, and a plug plugged in another of the paired ports. The plug has a hammer abutting against a wall of an opening provided in the optical receptacle to prevent the plug from slipping out from another of the paired ports. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other purposes, aspects and advantages will be better understood from the following detailed description of a preferred embodiment of the invention with reference to the drawings, in which: 
         FIG. 1  is an outer appearance of an optical transceiver according to the embodiment of the present invention; 
         FIG. 2  shows an inside of the bottom housing as removing the top housing; 
         FIG. 3  also shows an inside of the bottom housing; 
         FIG. 4  is a perspective view of the bi-directional optical sub-assembly (BOSA); 
         FIG. 5  is a perspective view of the plug; 
         FIG. 6  shows a cross section of the plug plugged into the second port; 
         FIG. 7  is a perspective view of the optical receptacle where the plug is set within the second port; 
         FIG. 8  is a plan view of the second port where the plug is set; 
         FIG. 9  shows a cross section taken along the line IX-IX appearing in  FIG. 8 ; 
         FIG. 10  is a cross section showing a mechanism to disassemble the plug from the optical transceiver; 
         FIG. 11  is a perspective view of a cross section of the port according to the second embodiment; and 
         FIG. 12  shows a cross section of the pillar and the hammer accompanied with the latch  26 ; 
         FIG. 13  is a plan view of the plug with the hammer and the pillar; and 
         FIGS. 14A to 14C  describe manipulation of the pillar after the plug is set within the port. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     (First Embodiment) 
     Some embodiments according to the present application will be described as referring to drawings. In the description of the drawings, numerals or symbols same with or similar to each other will refer to elements same with or similar to each other without duplicated explanations. 
       FIG. 1  is an outer appearance of an optical transceiver according to an embodiment of the present invention. As shown in  FIG. 1 , the optical transceiver  1  of the present embodiment has a rectangular housing whose longitudinal direction is in parallel to the optical axis A 1 . The housing  2  comprises a top housing  6  and a bottom housing  4  assembled with the top housing  6 . Two housings,  4  and  6 , form a cavity into which electrical components and optical components are installed. 
       FIGS. 2 and 3  show an inside of the bottom housing  4  by removing the top housing  6 . As shown in  FIGS. 2 and 3 , the bottom housing  4  provides a body portion  9  and an optical receptacle  3 . The body portion  9  and the optical receptacle  3  are arranged along the longitudinal direction of the housing  2 . The body portion  9  installs two circuit boards between which a holder  7  is mounted.  FIG. 3  omits the holder  7 . An interface between the body portion  9  and the optical receptacle  3  provides a shield plate  8  made of metal to shield the inside of the body portion  9 . In the description below, a direction “forward” or “front” corresponds to a side where the optical receptacle  3  is formed, while, another direction “rear” or “back” corresponds to a side where the holder  7  is mounted. 
     The optical receptacle  3  provides two ports,  11  and  12 . When an optical transceiver  1  has a type of the bi-directional transceiver that transmits and receives optical signals to and from a single fiber, respectively, like the present embodiment, one of the port  11  has functions of transmitting an optical signal and receiving another optical signal, but the other port  12  becomes a dummy port. On the other hand, the optical fiber has a function that the optical transmission and the optical reception are carried out with respect to respective fibers independent to the others, the first port  11  is provided for the optical transmission, and the second port  12  provides the function of the optical reception. 
     The body portion  9  installs a bi-directional optical sub-assembly (BOSA)  13  and a printed circuit board (PCB)  14  that mounts electronic circuits to communicate with the BOSA. The BOSA  13  is electrically connected to the PCB  14  by a flexible printed circuit (FPC) board  16 . 
       FIG. 4  is a perspective view of the BOSA  13 . The BOSA  13  has a cylindrical body with an axis A 1 , where a transmitter device  13   a  is provided as aligning the optical axis thereof with the axis A 1 . A receiver device  13   b , which also has a cylindrical shape, is provided along an axis A 2  intersecting with, or perpendicular to the former axis A 1 . Some lead terminals  13   c  extend along the axis A 2 . Other lead terminals, which are not illustrated in  FIG. 4 , extend from the transmitter device  13   a  along the axis A 1 . Although not illustrated in  FIG. 4 , a point AP at which two axes, A 1  and A 2 , intersect arranges a wavelength selective filter. That is, the wavelength selective filter transmits an optical signal provided from the transmitter device  13   a  to an external fiber set in the port  11 , and reflects another optical signal provided from the external fiber toward the receiver device  13   b . Thus, the bi-directional function with respect to the single fiber may be realized. 
     Referring to  FIG. 3  again, the FPC board  16  is split into two portions, one of which  16   a  is connected to the transmitter device  13   a  and the other  16   b  is connected to the receiver device  13   b , but collectively connected to the PCB  14 . The portion  16   a  of the FPC  16  extends from the edge of the PCB  14  to the transmitter device  13   a  as bending thrice to form a U-shaped side view. That is, the FPC  16   a  is bent upward at an edge of the splitting, bent forward and bent downward to form the U-shape. The other FPC  16   b  is twisted between the edge of the splitting and the receiver device  13   b  because the axis A 2  for the receiver device  13   b  makes a right angle against the axis A 1 . 
     As already described, the optical transceiver  1  of the present embodiment is the type of the bi-directional transceiver for the single fiber, the second port  12  is the dummy port. Accordingly, it is preferable to avoid the miss-insertion into the second port  12  of an external optical connector. Also, during the production of the optical transceiver, it should be avoided to miss-assemble of the BOSA in the second port  12 . So, the optical transceiver  1  of the present embodiment provides a plug  17  set into the second port  12 . 
     The second port  12  is independent of the transmitter device  13   a  and the receiver device  13   b , that is, the second port is electrically and optically isolated from two devices,  13   a  and  13   b . Accordingly, even when an external optical connector is inserted into the second port  12 , optical and electrical components installed in the optical transceiver  1  may receive no influence from such an insertion. Also, optical and electrical components in another optical transceiver coupled with the external connector may also receive no influence even when the optical connector is inserted into the second port  12 . The miss-insertion of the optical connector into the second port  12  only brings the interruption of the communication. 
       FIG. 5  is a perspective view of the plug  17 . The plug  17  primarily comprises three portions. That is, the plug  17  provides a plug body  18 , a knob  19 , and a latch  26 . The plug body  18  is to be inserted into the second port  12 . The knob  19  determines an insertion depth of the plug body  18  into the second port  12 , and the latch  26  prevents the plug body  18  from slipping out from the second port  12 . 
     The plug body  18  has a cross section of an H-shape with a center wall  18   a  and two slabs  18   b  extending laterally from respective ends of the center wall  18   a , but outer dimensions of the plug body  18  are slightly smaller than inner dimensions of the second port  12  by about 10 μm. The respective slabs  18   b  provide in the ends thereof ribs  18   c . The center wall  18   a  and the slabs  18   b  form cavities in respective sides of the center wall  18   a . The plug  17  of the present embodiment may save resin materials forming the plug  17  without degrading stiffness thereof. 
       FIG. 6  shows a cross section of the plug  17  in a state the plug  17  is plugged into the second port  12 . A distance between tips of the ribs  18   c  provided in respective sides of the slabs  18   b is designed to be slightly wider than an inner width W 1  of the second port  12  before the plug  17  is set in the second port  12 . Moreover, the plug  17  is plugged within the second port  12  as crushing the ribs  18   c . Thus, the plug  17  is tightly set in the second port  12  without looseness. 
     Referring to  FIG. 5 , the plug  17  provides in the front end thereof a cap  22  including a pocket  22   a  of a circular hollow. The pocket  22   a  may facilitate the picking up the bail  5  by fingers when the optical transceiver  1  is pulled out from the cage. The cap  22  also provides the knobs  19  in respective ends to determine the position of the plug  17  in the second port  12  along the longitudinal direction, or the insertion depth of the plug  17  in the second port  12 . That is, referring to  FIG. 7 , which is a perspective view of the optical receptacle  3  where the plug  17  is set in the second port  12 , the first and second ports,  11  and  12 , each provides a pair of hollows  23  in respective sides thereof. The knobs  19  are set within respective hollows  23 . Designing the depth of the hollow  23  and the length of the knob  19  each along the longitudinal direction, the depth of the plug  17  into the second port  12  may be optionally determined. 
     The receptacle  3  needs a function to latch the plug  17 , that is, a mechanism to prevent the plug  17  from slipping out from the second port  12 .  FIG. 8  is a plan view of the second port  12  where the plug  17  is set. As shown in  FIG. 8 , the optical transceiver  1  of the present embodiment provides such a mechanism  21  including the latch  26  in the plug  17  and an opening  28  in the second port  12  of the receptacle  3 . The first port  11  also provides an opening to prevent the optical connector set therein from slipping out from the first port  11 . 
     The second port  12  provides the port  25 , into which the plug  17  is set, exposing from the front end of the optical receptacle  3 . The port  25  is continued to the opening  28  by a channel  29  with a width of W 3 . Specifically, the opening  28  in a width W 5  thereof is wider than the width W 3  of the channel  29 , which forms stoppers  24  in respective sides of the channel  29 . Also, the width W 3  of the channel  29  is narrower than a width W 4  of the port  25 . 
       FIG. 9  shows a cross section taken along the line IX-IX appearing in  FIG. 8 . As shown in  FIG. 9 , the latch  26  of the plug  17 , which extends from the slab  18   b  frontward, has a root  26   a  continuous from the slab  18   b , an arm  26   c  extending from the root  26   a , and a tip  26   b  in the end of the arm  26   c . Because the latch  26  continues to the slab  18   b  only by the root  26   a  thereof, and the arm  26   c  has a thickness thinner than that of the slab  18   b , the tip  26   b  may flap up and down by the root  26   a  as a fulcrum of the flapping. The tip  26   b  of the latch  26  provides the hammer  27  abutting against the stopper  24 . 
     Referring to  FIG. 8  again, the hammer  27  has a width W 6  is larger than a width W 7  of the arm  26   c  of the latch  26  and the width W 3  of the channel  29  but slightly narrower than the width W 5  of the opening  28 . When the plug  17  is set in the second port  12 , the hammer  27  is set in the opening  28  and respective sides thereof are in contact with the stopper  24 . Inserting the plug  17  into the second port  12 , the arm  26   c  of the latch  26  is easily bent from the root  26   a  such that the hammer  27  slides on the bottom surface  24   a  of the stopper  24 . Further inserting the plug  17  until the knob  19  abuts against the deep end of the hollow  23 , the hammer  27  is apart from the stopper  24  by a gap S therebetween. That is, under such a condition, the tip  26   b  of the latch  26  and the hammer  27  may recover the original position by the elasticity of the arm  26   c . Because the level of the hammer  27  in the original position is higher than the level of the bottom surface  24   a  of the stopper  24 , the hammer  27  abuts against the side surface of the stopper  24 , namely, the edge of the opening  28 , which effectively prevents the plug  17  from slipping out from the second port  12 . The tip  26   b  and the hammer  27  may be pressed down by a tool through the opening  28  to release the hammer  27  from the stopper  24 . However, a specific tool is necessary to press down the hammer  27 . 
     Recent electronic components and/or electronic apparatus are requested to be recycled when they are casted away. Accordingly, such components and apparatuses are necessary to be easily disassembled and grouped depending on materials constituting them. The plug  17  of the present embodiment, because of the mechanism of the latch  26  and the stopper  24 , is hard to be disassembled from the optical transceiver  1 . Some specific tools, T 1  and T 2 , shown in  FIG. 10  could be helpful to disassemble the plug  17  from the optical transceiver  1 .  FIG. 10  is a cross section showing a mechanism to disassemble the plug  17  from the optical transceiver  1 . The plug  17  provides a terrace  30  to which the tool T 1  is hooked. Referring to  FIG. 5  again, the terrace  30  is provided in the top of the plug  17  and faces the front end of the hammer  27 . The rear edge  30   a  of the terrace  30  is positioned in the channel  29  with a space against the hammer  27 . Accordingly, the tool T 1  may be hooked with the edge  30   a  to pull the plug  17 . On the other hand, another tool T 2  pushes the hammer  27  and/or the latch  26  downward to release the hammer  27  from the wall of the opening. Thus, the plug  17  is able to be extracted from the second port  12 . 
     The optical transceiver  1  of the present embodiment receives the external optical connector only in the first port  11 . The BOSA  13 , which provides the transmitter device  13   a  and the receiver device  13   b,  optically couples with the single fiber secured in the optical connector. On the other hand, the other port  12  is plugged with the plug  17 , and the plug  17  is hard to be split out from the second port because of the hammer  27  abutting against the wall of the opening  28 . Accordingly, the miss-insertion of the optical connector may be effectively prevented. The optical receptacle  3  provided in the present optical transceiver  1  has the configuration completely same as that provided in an optical transceiver receiving a pair of optical connectors, one of which is for the optical reception and the other is for the optical transmission. Thus, the optical transceiver  1  of the present embodiment may save the production cost. 
     (Second Embodiment) 
     The plug  17  of the former embodiment, as already described, is prevented to be split off from the second port  12  because of the abutting mechanism of the hammer  27  against the wall of the opening  28 . However, also already described, a combination of the tools, T 1  and T 2 , one for pulling the plug  17  and the other for pushing the hammer  27 , may easily release the plug  17  from the port  12 . For instance, a tweezers may push the hammer  27  downward as the tool T 2 . The second embodiment of the present invention provides an additional mechanism making it harder to remove the plug  17  from the port  12 . 
       FIG. 11  is a perspective view of a cross section of the port  12  according to the second embodiment that provides a pillar  31  and a pocket  32  in the hammer  27 .  FIG. 12  shows a cross section of the pillar  31  and the hammer  27  accompanied with the latch  26 , and  FIG. 13  is a plan view of the plug  17 A with the hammer  27  and the pillar  31 . The pillar  31 , which is set between the hammer  27  and the cap  22 , has a root  31   a  fixed to the slab  18   b  and a tip  31   b  in a level thereof substantially equal to the hammer  27 . The tip  31   b  may flap front and rear by the root  31   a  as a center of the flapping. Referring to  FIG. 13 , the pillar  31  has a lateral width W 8  narrower than the lateral width W 7  of the hammer  27 . The tip  31   b  of the pillar  31  provides a slope  31   c  inclined toward the hammer  27 . 
     The pocket  32 , which is formed by two banks  33  and  34  provided in the back surface  27   a  of the hammer  27 , receives the tip  31   b  of the pillar  31 . The former banks  33  has a slope  33   a  facing the slope  31   c  of the pillar  31 . The longitudinal width W 9  of the pocket  32  between two banks,  33  and  34 , is wider than a longitudinal width W 10  of the pillar  31 . The pillar  31 , when the plug  17 A is not plugged into the port  12 , is free from the hammer  27 . That is, the pillar  31  in the tip  31   b  thereon is in a position not to interrupt the flapping of the hammer  27  by being positioned in front of the hammer  27 . 
       FIGS. 14A to 14C  describe manipulation of the pillar  31  after the plug  17 A is set within the port  12 . As shown in  FIG. 14A , a tool  36 , which may be a bar and/or a slab, is inserted from a gap between the terrace  30  and the top of the optical receptacle  3 , and pushes the pillar  31  rearward. Deforming the pillar  31  toward the hammer  27 , the slope  31   c  in the tip  31   b  of the pillar  31  comes in contact with the slope  33   a  of the front bank  33  of the hammer  27 , which is shown in  FIG. 14B . Further pushing the pillar  31  by the tool  36  in rearward, the slope  31   c  in the tip  31   b  of the pillar  31  is slid on the slope  33   a  of the bank  33 , which raises the hammer  27  upward. Finally, the tip  31   b  of the pillar  31  gets over the bank  33  and is set within the pocket  32 , as shown in  FIG. 14C . Thus, the pillar  31  is necessary to have a length from the root  31   a  to the tip  31   b  such that the tip  31   b  is stably set within the pocket  32 . The pillar  31 , once set within the pocket  32 , may perfectly prevent the hammer  27  from flapping downward to release the abutment against the wall of the opening  28 . The plug  17 A is unable to be removed from the port  12  without breaking the pillar  31 . 
     In the foregoing detailed description, the method and apparatus of the present invention have been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the present invention. The present specification and figures are accordingly to be regarded as illustrative rather than restrictive.