Abstract:
In an optical connector for connecting an optical fiber to a mating object having a pair of guide members, the optical connector includes a connector body fixed to the optical fiber and an adapter removably attached to the connector body. The adapter has a positioning groove for positioning an end portion of the optical fiber and a pair of guide grooves adapted to receive the guide members, respectively.

Description:
[0001]     This application claims priority to prior Japanese application JP 2004-307674, the disclosure of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to an optical connector for use in connecting an optical fiber.  
         [0003]     In recent years, there is a strong demand for an increase in capacity of optical communication using an optical fiber. Further, in order to reduce the size of an optical communication apparatus, use is made of a PLC (Planar Lightwave Circuit) comprising a silicon or a quartz substrate and a plurality of optical waveguides integrated thereon. In particular, in DWDM (Dense-Wavelength Division Multiplexing), an AWG (Arrayed Waveguide Grating) as one type of the PLC is used so that optical signals transmitted from a plurality of transceivers and different in wavelength from one another can be transmitted by a single optical fiber.  
         [0004]     Traditionally, in order to achieve coupling between a number of optical waveguides on the PLC and a number of optical fibers, a component called a fiber array is sometimes used. The fiber array has a number of V grooves. The optical fibers are disposed in the V grooves of the fiber array, respectively, and adhered and fixed thereto. Then, light is transmitted through the optical fibers in the fiber array and the optical waveguides of the PLC and optical power of the light is monitored. When the optical power becomes maximum, the fiber array is adhered and fixed to the PLC.  
         [0005]     The above-mentioned technique is called active alignment. The active alignment requires a power monitor and a device for aligning the optical waveguides and the optical fibers in three directions, i.e., back-and-forth, left-and-right, and vertical directions upon coupling the optical waveguides and the optical fibers. Further, a considerably long operating time is required.  
         [0006]     Japanese Patent (JP-B) No. 2843338 discloses another example of coupling optical waveguides and optical fibers. The optical waveguides are formed on an optical waveguide substrate. The optical waveguides have end portions located on the optical waveguide substrate in the vicinity of an end face thereof. On opposite sides of the end portions of the optical waveguides, a pair of guide pins are fixed. Each of the guide pins protrudes from the end face of the optical waveguide substrate by about a half of its length.  
         [0007]     On the other hand, an optical fiber plug is fixed to end portions of the optical fibers. The optical fiber plug has a pair of receiving holes formed on opposite sides of the end portions of the optical fibers. By inserting the guide pins into the receiving holes, connection between the optical waveguides and the optical fibers is automatically achieved.  
         [0008]     With the above-mentioned structure, it is easy to align the optical waveguides and the optical fibers. However, when the guide pins are inserted into the receiving holes, a part of the optical fiber plug which is adjacent to each receiving hole may be damaged by the guide pin. Upon occurrence of such damage, stable alignment is difficult to perform. In order to perform stable alignment, a whole of the optical fiber plug which has been damaged must be replaced by a new optical fiber plug. This requires a relatively high cost.  
       SUMMARY OF THE INVENTION  
       [0009]     It is therefore an object of this invention to provide an optical connector which is capable of easily aligning an optical fiber and an object to be connected and which does not require a high cost for replacement of a part susceptible to damage.  
         [0010]     Other objects of the present invention will become clear as the description proceeds.  
         [0011]     According to an aspect of the present invention, there is provided a n optical connector for connecting an optical fiber to a mating object having a pair of guide members, the optical connector comprising a connector body fixed to the optical fiber and an adapter removably attached to the connector body, the adapter having a positioning groove for positioning an end portion of the optical fiber and a pair of guide grooves adapted to receive the guide members, respectively. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0012]      FIG. 1  is a perspective view of an optical connector according to an embodiment of this invention and an optical waveguide substrate in an unconnected state;  
         [0013]      FIG. 2  is an enlarged perspective view of a characteristic part of the optical waveguide substrate;  
         [0014]      FIG. 3  is a perspective view showing a state immediately before the optical connector and the optical waveguide substrate are connected to each other;  
         [0015]      FIG. 4A  is a front perspective view of a whole of the optical connector;  
         [0016]      FIG. 4B  is an enlarged view of a characteristic part in  FIG. 4A ;  
         [0017]      FIG. 5  is a perspective view of the optical connector alone;  
         [0018]      FIG. 6  is a perspective view of the optical connector when an adapter is removed from a plug;  
         [0019]      FIG. 7A  is a sectional view of a whole of the optical connector;  
         [0020]      FIG. 7B  is an enlarged view of a characteristic part in  FIG. 7A ;  
         [0021]      FIG. 8  is an enlarged perspective view of a part of the optical connector for describing an example of a damage;  
         [0022]      FIG. 9A  is a perspective view for describing an operation of attaching and removing the adapter from the optical connector; and  
         [0023]      FIG. 9B  is a perspective view for describing the adapter removed from the optical connector. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0024]     Referring to  FIGS. 1 through 3 , description will be made of an optical connector according to an embodiment of this invention.  
         [0025]     The optical connector depicted at  1  comprises a plug  2  as a connector body and an adapter  4  removably attached to one end of the plug  2 . To the plug  2 , a number of optical fibers  3  arranged in parallel are attached. The optical fibers  3  are extracted from the other end of the plug  2 .  
         [0026]     The optical connector  1  is adapted to be connected to an optical waveguide substrate  11 . The optical waveguide substrate  11  is provided with a plurality of optical waveguide elements, which are arranged along an upper surface of the optical waveguide substrate  11  and will collectively be called an optical waveguide  12 . The optical waveguide  12  has an end portion located in the vicinity of an end face of the optical waveguide substrate  11 . The optical waveguide substrate  11  is provided with a pair of guide pins  13  formed on opposite sides of the end portion of the optical waveguide  12 . Each of the guide pins  13  has a circular section in a cross-section thereof. As shown in  FIG. 2 , the guide pins  13  are disposed in a pair of V grooves  11   a  formed on the optical waveguide substrate  11 .  
         [0027]     Referring to  FIG. 3 , in a state immediately before the optical connector  1  is coupled to the optical waveguide substrate  11 , ends of the guide pins  13  of the optical waveguide substrate  11  are started to be inserted into a pair of guide grooves  6   b  of the adapter  4  of the optical connector  1 .  
         [0028]     Referring to  FIGS. 4A and 4B , the adapter  4  will be described.  
         [0029]     The details of the adapter  4  will later be described with reference to  FIG. 9B . The adapter  4  comprises an adapter body  5 , a silicon substrate  6 , a holding plate  7 , and a cover  8 . The silicon substrate  6  has an upper surface provided with a number of positioning grooves  6   a  having a V-shaped section and formed at a center portion thereof with a predetermined pitch. The positioning grooves  6   a  serve to position the optical fibers  3 . The optical fibers  3  are inserted into the positioning grooves  6   a  to be aligned. The silicon substrate  6  is provided with a pair of guide grooves  6   b  formed on left and right sides of the positioning grooves  6   a  to receive the guide pins  13 . Each of the guide grooves  6   b  has a V-shaped section in a cross-section thereof.  
         [0030]     Referring to FIGS.  5  to  7 B, description will be made of the relationship between the plug  2  and the adapter  4  of the optical connector  1 .  
         [0031]     In  FIG. 5 , the adapter  4  is attached to the plug  2  to form the optical connector  1 . As shown in  FIG. 6 , the adapter  4  is removable from the plug  2 .  
         [0032]     The plug  2  is provided with a pair of through holes  2   a  formed on left and right sides of one end as an adapter receiving end to serve as engaging portions. The adapter body  5  of the adapter  4  is provided with a pair of guide portions  5   a  formed on left and right sides of a rear surface thereof and extending rearward. Each of the guide portions  5   a  is provided with a protrusion  5   b.    
         [0033]     Referring to  FIGS. 7A and 7B , the protrusions  5   b  of the adapter body  5  are engaged with the through holes  2   a  of the plug  2 , respectively. The details will later be described with reference to  FIGS. 9A and 9B .  
         [0034]     Referring to  FIG. 8 , description will be made of an example of a damage of the optical connector  1 .  
         [0035]     When the end of the guide pin  13  of the optical waveguide substrate  11  is not inserted at the center of the guide groove  6   b  of the adapter  4  but collides with a slightly outside position of a slope or ramp  6   b   1  of the guide groove  6   b , the slope  6   b   1  is assumed to be damaged as shown in the figure. In  FIG. 8 , a damaged portion is depicted by a reference numeral  9 .  
         [0036]     Upon occurrence of the damaged portion  9 , only the adapter  4  is replaced by a new adapter. In other words, the plug  2  need not be replaced by a new plug.  
         [0037]     Referring to  FIGS. 9A and 9B , description will be made of a structure of the adapter  4  and an operation of attaching and removing the adapter  4 .  
         [0038]     The silicon substrate  6  is mounted to the adapter body  5  of the adapter  4 . On the silicon substrate  6 , the holding plate  7  is placed. Further, the cover  8  is put on the holding plate  7 . By an elastic member (not shown) formed on the cover  8 , the upper surface of the silicon substrate  6  and a lower surface of the holding plate  7  are continuously kept in contact with each other. Therefore, precise center alignment of each optical fiber  3  is maintained. In this respect, Japanese Unexamined Patent Application Publication (JP-A) No. 2004-118031 discloses a similar structure.  
         [0039]     The guide portions  5   a  are formed on the rear surface of the adapter body  5  on left and right sides thereof. Each of the guide portions  5   a  has an inner guide portion  5   a   1 , an outer guide portion  5   a   2  connected to the inner guide portion  5   a   1  to form a generally U shape, and a manual operating portion  5   a   3  formed on a front side of the outer guide portion  5   a   2 . The protrusion  5   b  is formed on an outer surface of the outer guide portion  5   a   2 . Between the inner and the outer guide portions  5   a   1  and  5   a   2 , a gap  5   c  is formed so as to allow elastic deformation of the outer guide portion  5   a   2 .  
         [0040]     Next, description will be made of an operation of attaching the adapter  4  to the plug  2 . The operating portions  5   a   3  are pushed by two fingers in predetermined directions (depicted by arrows A 1  and A 2 ) in  FIG. 9A . Then, the outer guide portions  5   a   2  are elastically deformed towards the center. In this state, the guide portions  5   a  of the adapter body  5  are inserted inward from the front side of the plug  2 . Thereafter, the two fingers are released from the operating portions  5   a   3 . Then, the outer guide portions  5   a   2  are restored to their original positions. As a consequence, the protrusions  5   b  formed on the outer guide portions  5   a   2  are engaged with the through holes  2   a  of the plug  2 , as shown in  FIG. 7B .  
         [0041]     The operation of removing the adapter  4  from the plug  2  is reverse to the above-mentioned operation of attaching the adapter  4  to the plug  2 .  
         [0042]     Although this invention has thus far been described in conjunction with the preferred embodiment thereof, it will readily be possible for those skilled in the art to put this invention into practice in various other manners without departing the scope of the appended claims. Although the description has been made about the case where the connector body is a plug, the connector body may be a receptacle. As well as the above-mentioned connection of a plurality of optical fibers, a single optical fiber can be connected also as will readily be understood.