Abstract:
This optical receptacle has the following: a first surface that includes a first optical surface and a third optical surface; a reflective surface whereby the light inputted via the first optical surface is reflected in a direction parallel to a substrate; an optical separation unit whereby the light reflected off the reflective surface is separated into monitoring light and signal light; a transmitting surface through which the signal light separated out by the optical separation unit is transmitted; a third surface that includes a second optical surface via which the signal light that has been transmitted through the transmitting surface is outputted towards the end face of the aforementioned light-transporting body; and a reflected-monitoring-light avoidance means whereby monitoring light that has reached the detection element is guide so as not to return to the abovementioned light-emitting element.

Description:
TECHNICAL FIELD 
     The present invention relates to an optical receptacle for optically coupling a light emitting element with an end surface of an optical transmission member, and an optical module having the optical receptacle. 
     BACKGROUND ART 
     Conventionally, in optical communications using an optical transmission member such as an optical fiber and an optical waveguide, an optical module including a light emitting element such as a surface-emitting laser (for example, VCSEL: Vertical Cavity Surface Emitting Laser) has been used. 
     In such an optical module, an optical module component called an optical receptacle is used. The optical receptacle is used for light transmission via an optical fiber in such a manner that light containing communication information from a light emitting element is coupled to an end surface of the optical fiber. 
     In view of the use for photoelectric conversion devices of substrate mounting type, the Applicant has proposed an optical receptacle and an optical module having the optical receptacle which have a reflecting surface for reflecting a part of emission light emitted by a light emitting element to the detection device side as monitor light, and can simply and properly achieve light transmission in which the light of the light emitting element is taken out along the substrate direction at an end surface of the optical fiber (see PTL 1). 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1 
         Japanese Patent Application Laid-Open No. 2013-137507 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     In the above-described optical module disclosed in PTL 1, it is desired to further increase the optical property by preventing reflection light from the detection device from returning to the light emitting element. 
     An object of the present invention is to provide an optical receptacle and an optical module including the optical receptacle which provide a further improved optical property while maintaining the conventional optical property by preventing reflection light from the detection device from returning to the light emitting element. 
     Solution to Problem 
     To solve the above-described object, an optical receptacle according to the embodiments of the present invention is disposed between a photoelectric conversion device and an optical transmission member, the photoelectric conversion device including a light emitting element and a detection device configured to detect monitor light for monitoring light emitted from the light emitting element, the light emitting element and the detection device being mounted on a substrate, the optical receptacle being configured to optically couple the light emitting element and an end surface of the optical transmission member, the optical receptacle including: a first surface including a first optical surface on which light emitted from the light emitting element is incident, and a third optical surface configured to emit the monitor light toward the detection device; a reflecting surface configured to reflect light incident on the first optical surface in a direction along the substrate; a light separation part composed of a part of an internal surface of a recess disposed on a light path of light reflected by the reflecting surface, the light separation part being configured to separate the light reflected by the reflecting surface into the monitor light directed toward the third optical surface and signal light directed toward the end surface of the optical transmission member; a transmission surface composed of a part of the internal surface of the recess, and configured to allow the signal light separated by the light separation part to pass therethrough through an internal space of the recess; a third surface including a second optical surface configured to emit the signal light passed through the transmission surface toward the end surface of the optical transmission member; and a reflection monitor light avoiding part disposed on a light path between the light separation part and the detection device, and configured to guide reflection monitor light such that the reflection monitor light does not return to the light emitting element, the reflection monitor light being the monitor light which reaches the detection device and is reflected by a detection surface of the detection device. The light separation part includes: a division reflection surface on which a part of light emitted from the light emitting element and reflected by the reflecting surface is incident, the division reflection surface being divided in a predetermined dividing direction at predetermined intervals and disposed at a second inclination angle to the first surface angle, the division reflection surface being configured to reflect the part of the light incident on the division reflection surface as the monitor light; and a division transmission surface on which another part of the light of the light emitting element reflected by the reflecting surface is incident, the division transmission surface is disposed and divided at a position where the division reflection surface is not provided, the division transmission surface being configured to allow the other part of the light incident on the division transmission surface to pass therethrough toward the third surface side as the signal light. 
     In addition, an optical module according to the embodiments of the present invention includes: a photoelectric conversion device including a light emitting element and a detection device configured to detect monitor light for monitoring light emitted from the light emitting element, the light emitting element and the detection device being mounted on a substrate; and the above-mentioned optical receptacle disposed on the substrate. 
     Advantageous Effects of Invention 
     According to the present invention, the light emitted from the light emitting element and reflected by the detection surface of the detection device does not return to the light emitting element, and thus the optical property of the optical module can be further improved. In addition, the present invention can simply and properly achieve light transmission performed with monitoring in which the light emitted from the light emitting element is taken out in the direction along the substrate at an end surface of the optical transmission member. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a sectional view illustrating a configuration of an optical module according to Embodiment 1 of the present invention; 
         FIG. 2  is a plan view of an optical receptacle according to Embodiment 1; 
         FIG. 3  is a bottom view of the optical receptacle according to Embodiment 1; 
         FIG. 4  is a partially enlarged sectional view of a light separation part of Embodiment 1; 
         FIG. 5A  illustrates a spot shape of signal light at an end surface of an optical transmission member of Embodiment 1, and  FIG. 5B  illustrates an intensity distribution of signal light at an end surface of the optical transmission member; 
         FIG. 6  is a partially enlarged sectional view illustrating an exemplary reflection monitor light avoiding part; 
         FIG. 7  is a partially enlarged sectional view illustrating another exemplary reflection monitor light avoiding part; 
         FIG. 8  is a graph showing a relationship between variation of the quantity of reflection monitor light and variation of the inclination angle of the division reflection surface in the case where the central axis of a third optical surface is not changed; 
         FIG. 9  is a sectional view illustrating a configuration of an optical module according to a modification of Embodiment 1; 
         FIG. 10  is a plan view of an optical receptacle according to the modification of Embodiment 1; 
         FIG. 11  is a bottom view of the optical receptacle according to the modification of Embodiment 1; 
         FIG. 12  is a right side view of the optical receptacle according to the modification of Embodiment 1; 
         FIG. 13A  and  FIG. 13B  illustrate example configuration  1  of a light separation part in an example of Embodiment 1; 
         FIG. 14A  and  FIG. 14B  illustrate example configuration  2  of a light separation part in the example of Embodiment 1; 
         FIG. 15  illustrates a configuration of a light separation part according to Embodiment 2 of the present invention; 
         FIG. 16A  and  FIG. 16B  illustrate example configuration  1  of a light separation part in an example of Embodiment 2; 
         FIG. 17A  and  FIG. 17B  illustrate example configuration  2  of a light separation part in the example of Embodiment 2; 
         FIG. 18A  and  FIG. 18B  illustrate a configuration of a light separation part of Embodiment 3; 
         FIG. 19  illustrates a configuration of a third recess of a modification of Embodiment 3; 
         FIG. 20  illustrates a configuration of an optical module according to Embodiment 4; 
         FIG. 21A  to  FIG. 21C  show simulations of variation of the spot shape (cross-sectional shape) of signal light at different positions on the light path of the signal light in Embodiment 4; 
         FIG. 22  illustrates an intensity distribution of signal light at an end surface of the optical fiber in Embodiment 4; 
         FIG. 23A  is a sectional view illustrating a configuration of an optical module according to modification  1  of Embodiment 4, and  FIG. 23B  is a right side view thereof; 
         FIG. 24  illustrates a configuration of an optical module according to modification  2  of Embodiment 4; 
         FIG. 25A  to  FIG. 25C  show simulations of variation of the spot shape of signal light at different positions on the light path of the signal light in modification  2  of Embodiment 4; 
         FIG. 26A  is a sectional view illustrating a configuration of an optical module according to modification  3  of Embodiment 4, and  FIG. 26B  is a right side view thereof; 
         FIG. 27  is a sectional view illustrating a configuration of an optical module according to modification  4  of Embodiment 4; 
         FIG. 28A  to  FIG. 28C  show simulations of variation of the spot shape of signal light at different positions on the light path of the signal light in modification  4  of Embodiment 4; 
         FIG. 29A  is a sectional view illustrating a configuration of an optical module according to modification  5  of Embodiment 4, and  FIG. 29B  is a right side view thereof; 
         FIG. 30A  is a perspective view illustrating another exemplary light separation part, and  FIG. 30B  is a plan view thereof; and 
         FIG. 31A  is a partially enlarged sectional view of the light separation part, and  FIG. 31B  is a partially enlarged sectional view illustrating the light path of the light separation part. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the following, with reference to the accompanying drawings, an optical receptacle and an optical module including the optical receptacle according to the embodiments of the present invention will be described. 
     [Embodiment 1] 
       FIG. 1  is a sectional view illustrating a configuration of optical module  1  according to Embodiment 1 (which corresponds to a sectional view taken along line A-A of  FIG. 2 ).  FIG. 2  is a plan view of optical receptacle  2 .  FIG. 3  is a bottom view of optical receptacle  2 . 
     As illustrated in  FIG. 1 , optical receptacle  2  according to Embodiment 1 (optical receptacle main body) is disposed between photoelectric conversion device  3  and optical transmission member  5 . 
     Photoelectric conversion device  3  is a photoelectric conversion device of a substrate mounting type. Photoelectric conversion device  3  includes semiconductor substrate (circuit board)  6 , light emitting element  7  and detection device  8 . Semiconductor substrate (circuit board)  6  is parallel to lower end surface  2   a  of optical receptacle  2 . On the surface (top surface) of semiconductor substrate (circuit board)  6  on optical receptacle  2  side, one light emitting element  7  configured to emit (light emission) laser light La in a direction (upward direction) perpendicular to the surface is disposed. Light emitting element  7  is, for example, a vertical cavity surface emitting laser (VCSEL). In addition, at a position on the surface of semiconductor substrate  6  on optical receptacle  2  side and on the right side relative to light emitting element  7  in  FIG. 1 , one detection device  8  configured to receive monitor light M for monitoring the output (such as intensity and quantity) of laser light La emitted from light emitting element  7  is disposed. Detection device  8  is a photodetector, for example. Further, although not illustrated in the drawing, an electronic component such as a circuit configured to control the output of laser light La emitted (light emission) from light emitting element  7  based on the intensity and the quantity of monitor light M detected by detection device  8  is mounted on the surface of semiconductor substrate  6  on optical receptacle  2  side. The electronic component is electrically connected with light emitting element  7  and detection device  8  through a wiring. Photoelectric conversion device  3  is attached to optical receptacle  2  with a publicly known fixing member such as adhesive agent (such as thermosetting resin and ultraviolet curing resin) provided between semiconductor substrate  6  and optical receptacle  2 , for example. 
     Optical transmission member  5  is an optical fiber, an optical waveguide or the like, for example. In the present embodiment, optical transmission member  5  is an optical fiber. In addition, optical transmission member  5  may be a single mode optical fiber, or a multiple mode optical fiber. A portion having a predetermined length of optical transmission member  5  on end surface  5   a  side is detachably attached in cylindrical optical transmission member attaching portion  4  formed in optical receptacle  2  together with cylindrical ferrule  9  which holds the portion. In the state where ferrule  9  holding optical transmission member  5  is attached to optical receptacle  2 , a portion of optical transmission member  5  on end surface  5   a  side (a portion housed in optical transmission member attaching portion  4 ) is parallel to semiconductor substrate  6 . 
     In the state where optical receptacle  2  is disposed between photoelectric conversion device  3  and optical transmission member  5 , optical receptacle  2  optically couples light emitting element  7  and end surface  5   a  of optical transmission member  5 . Optical receptacle  2  includes first surface S 1 , reflecting surface  14 , light separation part  17 , third surface S 3 , and a reflection monitor light avoiding part. 
     As illustrated in  FIG. 1 , in optical receptacle  2 , the external shape of the principal part having various kinds of optical surfaces is formed in a substantially cuboid shape. That is, as illustrated in  FIG. 1  to  FIG. 3 , in the principal part of optical receptacle  2 , the rough external shape is defined by lower end surface  2   a , upper end surface  2   b , left end surface  2   c , right end surface  2   d , front end surface  2   e  and rear end surface  2   f . In addition, upper and lower end surfaces  2   a  and  2   b  are parallel to each other, and left and right end surfaces  2   c  and  2   d  are also parallel to each other. Further, upper and lower end surfaces  2   a  and  2   b , and left and right end surfaces  2   c  and  2   d  are perpendicular to each other. It is to be noted that optical transmission member attaching portion  4  described above is formed to protrude to the right side from right end surface  2   d . It should be noted that the present invention is not limited to this configuration, and in the case where optical receptacle  2  is produced by resin molding for example, a releasing taper for the release from the metal mold may be formed at left and right end surfaces  2   c  and  2   d.    
     As illustrated in  FIG. 1 , on lower end surface  2   a  of optical receptacle  2 , first recess  10  opening at lower end surface  2   a  and having a substantially trapezoidal cross-sectional shape is formed. In addition, the bottom surface of first recess  10  is first surface S 1  including first optical surface  11  on which laser light La emitted from light emitting element  7  is incident and third optical surface  13  from which monitor light M directed toward detection device  8  is emitted. As illustrated in  FIG. 1 , first surface S 1  is parallel to lower end surface  2   a . As illustrated in  FIG. 1  and  FIG. 3 , one first optical surface  11  is formed in a region around a left end portion on first surface S 1  in  FIG. 1  and  FIG. 3 . As illustrated in  FIG. 1  and  FIG. 3 , first optical surface  11  is a spherical or aspherical convex lens surface having a circular shape in plan view and projecting toward light emitting element  7  side. Preferably, first optical axis (central axis) OA ( 1 ) on optical surface  11  is aligned with the central axis of (central light beam) laser light La emitted from light emitting element  7  (light flux). In addition, the axis direction of optical axis OA ( 1 ) may be perpendicular to first surface S 1 . 
     As illustrated in  FIG. 1 , in the state where photoelectric conversion device  3  is attached to optical receptacle  2 , laser light La emitted from light emitting element  7  is incident on first optical surface  11  from below. Laser light La incident on first optical surface  11  becomes collimate light and advances in optical receptacle  2 . 
     In addition, as illustrated in  FIG. 1  and  FIG. 2 , upper end surface  2   b  of optical receptacle  2  is a second surface S 2  disposed on the side opposite to first surface S 1  (the upper side in  FIG. 1 ). At a position of second surface S 2  on the travelling direction side of laser light La relative to first optical surface  11  (at a position just above first optical surface  11  in  FIG. 1 ), reflecting surface  14  is formed such that reflecting surface  14  is tilted to the right side toward the upper side (or such that the distance to optical transmission member attaching portion  4  decreases toward upper end surface  2   b  side from lower end surface  2   a  side of optical receptacle  2 ) at a predetermined first inclination angle relative to first surface S 1 . As illustrated in  FIG. 1 , reflecting surface  14  is composed only of an inclined surface of second recess  15  of a substantially trapezoidal cross-sectional shape which is formed downward on second surface S 2 . 
     As illustrated in  FIG. 1 , laser light La which is emitted from light emitting element  7  and is incident on first optical surface  11  is incident (internally incident) on reflecting surface  14  from the internal side of optical receptacle  2  at an incident angle greater than the critical angle from below in  FIG. 1 . Then, reflecting surface  14  totally reflects laser light La toward the right side in  FIG. 1 . 
     From the standpoint of simplifying the design and the dimensional accuracy measurement, the inclination angle of reflecting surface  14  is preferably 45 degrees counterclockwise relative to first surface S 1  (0 degree) in  FIG. 1 . 
     Further, as illustrated in  FIG. 1  and  FIG. 2 , at a position (a position on the right side) on the reflection direction side of laser light La which is emitted from light emitting element  7  to reflecting surface  14  in second surface S 2  and is reflected by reflecting surface  14 , third recess  16  having a substantially trapezoidal cross-sectional shape is disposed toward the lower side. 
     A portion (tilted portion) facing reflecting surface  14  in the internal surface of third recess  16  is light separation part  17 . Laser light La reflected by reflecting surface  14  is incident on light separation part  17  from the internal side of optical receptacle  2 . Laser light La of light emitting element  7  incident on light separation part  17  is separated by light separation part  17  into monitor light M directed toward first surface S 1  and signal light (light to be coupled with optical transmission member  5 ) Lc directed toward end surface  5   a  of optical transmission member  5 . 
     As illustrated in  FIG. 1 , at a position where right end surface  2   d  of optical receptacle  2  faces end surface  5   a  of optical transmission member  5 , one second optical surface  12  serving also as third surface S 3  is formed. As with first optical surface  11 , second optical surface  12  is a spherical or aspherical convex lens surface having a circular shape in plan view and projecting to end surface  5   a  side of optical transmission member  5 . It is to be noted that optical axis (central axis) OA ( 2 ) on second optical surface  12  is preferably aligned with the central axis of end surface  5   a  of optical transmission member  5 . 
     As illustrated in  FIG. 1 , signal light Lc separated by light separation part  17  is incident on second optical surface  12  from the internal side of optical receptacle  2 . Signal light Lc incident on second optical surface  12  is converged and emitted (condensed) toward end surface  5   a  of optical transmission member  5  by second optical surface  12 . 
     Now light separation part  17  is described in detail.  FIG. 4  is a partially enlarged sectional view of light separation part  17  of Embodiment 1. As illustrated in  FIG. 4 , light separation part  17  includes division reflection surface  18 , division transmission surface  19  and step surface  20 . 
     To be more specific, as illustrated in  FIG. 4 , division reflection surface  18  is tilted to first surface S 1  side (the lower side in  FIG. 4 ) (at a predetermined second inclination angle to first surface S 1 ) toward second optical surface  12  (third surface S 3 ) side (the right side in  FIG. 4 ). In addition, division reflection surface  18  is disposed at even intervals in the inclination direction of division reflection surface  18  (second inclination angle direction) as a predetermined dividing direction. To be more specific, division reflection surface  18  includes a plurality of belt-shaped reflecting surface parts  181  extending in a direction (a depth direction as seen in  FIG. 4 ) orthogonal to the inclination direction and the normal direction of division reflection surface  18 . Reflecting surface parts  181  are disposed on one inclined plane at the second inclination angle as a whole. Preferably, the second inclination angle is 45 degrees clockwise from first surface S 1  (0 degree) in  FIG. 4 . 
     As illustrated in  FIG. 4 , division transmission surface  19  is disposed in a region where division reflection surface  18  is not provided (mainly, the spaces between each reflecting surface part) such that division transmission surface  19  faces reflecting surface  14  in the reflection direction of laser light La of light emitting element  7 . To be more specific, division transmission surface  19  is composed of a plurality of belt-shaped transmission surface parts  191  extending along the longitudinal direction of reflecting surface part  181  (the depth direction as seen in  FIG. 4 ). Each transmission surface part  191  is continuously connected with adjacent reflecting surface part  181  on the first surface S 1  side, and is disposed such that each transmission surface part  191  is orthogonal to the incident direction of laser light La with respect to transmission surface part  191 . It is to be noted that each transmission surface part  191  may also be disposed such that each transmission surface part  191  is orthogonal to first surface S 1 . 
     In addition, as illustrated in  FIG. 4 , step surface  20  is disposed between transmission surface part  191  and reflecting surface part  181  adjacent to transmission surface part  191  on the second surface S 2  side. In addition, step surface  20  is disposed such that step surface  20  is parallel to the incident direction of laser light La of light emitting element  7  with respect to light separation part  17 . 
     In light separation part  17 , a part of laser light La of light emitting element  7  reflected by reflecting surface  14  is incident on division reflection surface  18  at an incident angle greater than the critical angle, and another part of that laser light La is perpendicularly incident on division transmission surface  19 . 
     The part of laser light La incident on division reflection surface  18  is totally reflected by division reflection surface  18  toward first surface S 1  side as monitor light M. 
     The other part of laser light La incident on division transmission surface  19  passes through division transmission surface  19  toward the second optical surface  12  side as signal light Lc. At this time, since the other part of laser light La incident on division transmission surface  19  perpendicularly passes through division transmission surface  19 , the signal light Lc is not refracted. 
     In addition, at this time, laser light La is not incident on step surface  20  since step surface  20  is formed in a direction parallel to the incident direction of laser light La. 
     As illustrated in  FIG. 1  and  FIG. 2 , the part (right internal surface) opposed to light separation part  17  in the internal surface in third recess  16  with the internal space (air layer) of third recess  16  therebetween is transmission surface  21 . Signal light Lc separated by light separation part  17  is perpendicularly incident on transmission surface  21  through the internal space of third recess  16 . Then, transmission surface  21  allows the incident signal light Lc to perpendicularly pass therethrough toward second optical surface  12 . At this time, signal light Lc is not refracted since signal light Lc perpendicularly passes through transmission surface  21 . 
     In addition, as illustrated in  FIG. 1  and  FIG. 3 , one third optical surface  13  is formed in a region around the right end part on first surface S 1 . As illustrated in  FIG. 1  and  FIG. 3 , as with first optical surface  11 , third optical surface  13  is a spherical or aspherical convex lens surface having a circular shape in plan view and projecting toward detection device  8  side. It is to be noted that the axis direction of optical axis (central axis) OA ( 3 ) on third optical surface  13  may be perpendicular to first surface S 1 . 
     As illustrated in  FIG. 1 , monitor light M totally reflected by division reflection surface  18  is incident on third optical surface  13  from the internal side of optical receptacle  2 . Then, the internally incident monitor light M is converged and emitted toward detection device  8  by third optical surface  13 . 
     Further, in the present embodiment, at a middle position of the light path of monitor light M reflected by division reflection surface  18  and the light path of reflection monitor light RM (so-called return light) reflected by the light reception surface of detection device  8  and advancing toward light emitting element  7  (the light path between light separation part  17  and the light reception surface of detection device  8 ), a reflection monitor light avoiding part configured to guide reflection monitor light RM is disposed at a position away from light emitting element  7 .  FIG. 6  is a partially enlarged sectional view illustrating an example of the reflection monitor light avoiding part.  FIG. 7  is a partially enlarged sectional view illustrating another example of the reflection monitor light avoiding part. In the present embodiment, as illustrated in  FIG. 6 , the reflection monitor light avoiding part is division reflection surface  18  which is set at the second inclination angle such that the optical axis of monitor light M is tilted relative to first surface S 1 . In addition, as illustrated in  FIG. 7 , the reflection monitor light avoiding part is third optical surface  13  whose central axis is set to intersect with the normal direction relative to first surface S 1 . Preferably, the changed angle is an angle at which the quantity of reflection monitor light RM which reaches light emitting element  7  is 0. It is to be noted that the reflection monitor light avoiding part may be a combination of division reflection surface  18  in which the second inclination angle is set such that the optical axis of monitor light M is tilted relative to first surface S 1 , and third optical surface  13  whose central axis is set to intersect with the normal direction relative to first surface S 1 . 
     In optical module  1  according to the present embodiment having the above-mentioned configuration, laser light La of light emitting element  7  incident on first surface S 1  is reflected by reflecting surface  14 , and the laser light La is separated into monitor light M and signal light Lc by reflection at division reflection surface  18  of light separation part  17  and transmission at division transmission surface  19  of light separation part  17 . Then, monitor light M is emitted from first surface S 1  to detection device  8  side, and signal light Lc is emitted from third surface S 3  to end surface  5   a  side of optical transmission member  5 . Thus, acquisition of monitor light M and taking out of signal light Lc in a direction along semiconductor substrate  6  at end surface  5   a  of optical transmission member  5  can be easily performed. 
     In addition, in optical module  1  according to the present embodiment, division reflection surface  18  is formed such that the optical axis of monitor light M tilted relative to the detection surface of detection device  8 , and consequently monitor light M reflected by division reflection surface  18  obliquely reaches the detection surface of detection device  8 . A part of monitor light M reaching the detection surface is reflected toward third optical surface  13  as reflection monitor light RM. At this time, the optical axis of reflection monitor light RM is tilted relative to the central axis of third optical surface  13 . Thus, reflection monitor light RM is guided to a position away from light emitting element  7  (see Table 1 and  FIG. 8 ). 
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                 Inclination angle of division reflection surface (°) 
               
             
          
           
               
                   
                 3.0 
                 2.5 
                 2.0 
                 1.5 
                 1.0 
                 0.5 
                 0.0 
                 −0.5 
                 −1.0 
                 −1.5 
                 −2.0 
                 −2.5 
                 −3.0 
               
               
                   
                   
               
             
          
           
               
                 Inclination 
                 −5.0 
                 0.0 
                 0.2 
                 1.0 
                 1.5 
                 2.1 
                 1.6 
                 1.1 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
               
               
                 angle of 
                 −4.5 
                 0.0 
                 1.0 
                 2.1 
                 3.2 
                 3.5 
                 2.2 
                 1.5 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
               
               
                 central axis 
                 −4.0 
                 0.0 
                 0.0 
                 3.7 
                 4.2 
                 4.8 
                 3.5 
                 2.1 
                 0.2 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
               
               
                 of third 
                 −3.5 
                 0.0 
                 0.0 
                 2.3 
                 3.2 
                 5.3 
                 4.1 
                 3.2 
                 1.2 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
               
               
                 optical 
                 −3.0 
                 0.0 
                 0.0 
                 0.6 
                 2.4 
                 4.6 
                 4.3 
                 4.2 
                 2.1 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
               
               
                 surface (°) 
                 −2.5 
                 0.0 
                 0.0 
                 0.0 
                 2.3 
                 4.2 
                 3.5 
                 3.5 
                 1.3 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 −2.0 
                 0.0 
                 0.0 
                 0.0 
                 2.1 
                 3.9 
                 3.1 
                 2.0 
                 1.3 
                 0.3 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 −1.5 
                 0.0 
                 0.0 
                 0.0 
                 1.6 
                 4.2 
                 5.6 
                 5.4 
                 3.7 
                 2.2 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 −1.0 
                 0.0 
                 0.0 
                 0.0 
                 1.4 
                 6.4 
                 7.3 
                 8.5 
                 6.5 
                 3.9 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 −0.5 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 4.2 
                 6.2 
                 6.2 
                 4.2 
                 3.1 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 1.2 
                 1.6 
                 1.3 
                 0.9 
                 1.1 
                 0.6 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 0.5 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 3.2 
                 3.4 
                 4.5 
                 5.4 
                 4.3 
                 2.1 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 1.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 4.5 
                 6.3 
                 9.3 
                 9.1 
                 8.7 
                 3.2 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 1.5 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 4.2 
                 5.2 
                 5.3 
                 4.3 
                 2.1 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 2.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 2.1 
                 1.0 
                 1.4 
                 1.3 
                 0.9 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 2.5 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 1.5 
                 3.4 
                 3.5 
                 3.1 
                 1.3 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 3.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 1.2 
                 5.9 
                 4.5 
                 8.3 
                 4.2 
                 0.7 
                 0.0 
                 0.0 
               
               
                   
                 3.5 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 1.0 
                 6.2 
                 6.5 
                 5.3 
                 2.5 
                 2.1 
                 0.0 
                 0.0 
               
               
                   
                 4.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.3 
                 1.0 
                 1.2 
                 1.5 
                 0.7 
                 1.4 
                 0.0 
                 0.0 
               
               
                   
                 4.5 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 1.5 
                 2.3 
                 3.1 
                 1.4 
                 1.0 
                 0.5 
                 0.0 
               
               
                   
                 5.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 0.0 
                 1.8 
                 3.2 
                 5.1 
                 3.1 
                 4.0 
                 0.2 
                 0.0 
               
               
                   
               
             
          
         
       
     
     Table 1 shows the quantity of reflection monitor light RM at a position of light emitting element  7  in the case where the inclination angle of division reflection surface  18  is changed stepwise by 0.5 degrees from the second inclination angle (45 degrees), and central axis OA ( 3 ) of third optical surface  13  is changed stepwise by 0.5 degrees from the normal direction of first surface S 1 . The quantity of reflection monitor light RM is represented by a ratio with the quantity of laser light La emitted from light emitting element  7  set to 100%. In addition, in  FIG. 6 , plus (+) represents the case where the inclination angle of division reflection surface  18  is changed clockwise, and minus (−) indicates the case where the inclination angle of division reflection surface  18  is changed counterclockwise. In addition, in  FIG. 6 , plus (+) indicates the case where central axis OA ( 3 ) of third optical surface is changed clockwise, and minus (−) indicates the case where central axis OA ( 3 ) of third optical surface is changed counterclockwise.  FIG. 8  shows the quantity of light of the state of the change angle=0 (the configuration of  FIG. 6 ) where central axis OA ( 3 ) of third optical surface  13  of Table 1 is aligned with the normal direction relative to first surface S 1 .  FIG. 8  also shows the quantity of signal light Lc (quantity of light of approximately 50%) and the quantity of monitor light M (quantity of light of approximately 30%). 
       FIG. 8  is a graph showing a relationship between variation of the quantity of reflection monitor light and variation of the inclination angle of the division reflection surface in the case where the central axis of the third optical surface is not changed. As shown in Table 1 and  FIG. 8 , it was confirmed that, in the case of the configuration illustrated in  FIG. 6 , the returning of reflection monitor light RM to light emitting element  7  can be surely prevented by changing division reflection surface  18  by +1.5 degrees or more, or by −2.0 degrees or more. In addition, it was confirmed that, in the case where the configuration illustrated in  FIG. 6  and the configuration illustrated in  FIG. 7  are combined, the returning of reflection monitor light RM to light emitting element  7  can be surely prevented in a broad region where the quantity of light is 0 in Table 1. In actual design of the reflection monitor light avoiding part, it suffices to set the angle variation of division reflection surface  18  and the angle variation of central axis OA ( 3 ) of third optical surface  13  by selection from Table 1. Regarding the variation of the inclination angle of division reflection surface  18  and the variation of the inclination angle of central axis OA ( 3 ) of third optical surface  13 , the returning of reflection monitor light RM to light emitting element  7  can be prevented by variation of 0.5 degrees although it depends on the setting value of the other. When the reflection monitor light avoiding part is utilized, it is not necessary to tilt the mounted components and the like with respect to semiconductor substrate  6 , and further, it is not necessary to perform focus adjustment of optical surfaces  11  and  12  in the height direction (axis direction), thus making it possible to reduce assembly cost. In addition, when the reflection monitor light avoiding part is adopted in other embodiments and examples described later, the function of optical module  1  according to the present embodiment can be achieved. To be more specific, also in optical module  1  according to other embodiments and examples, the returning of reflection light from detection device  8  to light emitting element  7  can be prevented and the optical property can be further improved. 
       FIG. 5A  illustrates a spot shape of signal light on end surface  5   a  of optical transmission member  5  in Embodiment 1. As illustrated in  FIG. 5A , with the configuration in which division transmission surface  19  is divided, the cross sectional shape in a direction orthogonal to the travelling direction of signal light Lc can be set to a shape close to a circle as a whole. It is to be noted that the cross sectional shape of signal light Lc in  FIG. 5A  is a spot shape on end surface  5   a  of optical transmission member  5 . The X-axis direction in  FIG. 5A  indicates the longitudinal direction of reflecting surface part  181  in the radial direction of end surface  5   a  of optical transmission member  5 , and the Y-axis direction in  FIG. 5A  indicates the direction orthogonal to the longitudinal direction of reflecting surface part  181  in the radial direction of end surface  5   a  of optical transmission member  5 . In addition,  FIG. 5B  illustrates the intensity distribution of signal light Lc on a virtual YZ plane at end surface  5   a  of optical transmission member  5 . The Z-axis direction in  FIG. 5B  indicates the surface normal direction of end surface  5   a  (in other words, the incident direction of signal light Lc). Since such signal light Lc can be obtained, significant reduction in light coupling efficiency can be prevented even when a radial displacement is caused at optical transmission member  5  to a certain degree. Thus, in optical module  1 , light transmission performed with monitoring can be properly performed. In addition, since such proper light transmission is ensured, the positional accuracy of optical transmission member  5  with respect to optical receptacle  2  can be moderated. 
     Further, in optical module  1  according to the present embodiment, division reflection surface  18  is disposed on one plane. Thus, in the case of metal mold working where optical receptacle  2  is molded with use of an injection molding metal mold with resin, it suffices to create the shape transfer surfaces of division transmission surface  19  and step surface  20  between the shape transfer surfaces of division reflection surface  18  by groove working in the front-rear (upper and lower in  FIG. 2 ) direction with use of a tool (cutting tool or the like). Thus, a metal mold having favorable dimensional accuracy can be simply and quickly obtained at low cost. In addition, in this case, by forming unavoidable step surface  20  such that the surface is parallel to the light path, the influence of step surface  20  on the optical performance can be reduced as much as possible. 
     In addition, with first optical surface  11  and second optical surface  12 , the optical coupling between light emitting element  7  and end surface  5   a  of optical transmission member  5  can be efficiently performed, and with third optical surface  13 , monitor light M can be efficiently coupled with detection device  8 . 
     In addition, in optical module  1  according to the present embodiment, first optical surface  11  is formed to convert incident laser light La into collimate light (parallel light) having a constant light flux diameter, and thus only collimate light can be used inside optical receptacle  2 . Thus, even when dimensional error in the travelling direction of collimate light La, Lc, and M is caused in optical receptacle  2 , it is possible to properly ensure the quantity of coupling light (in other words, coupling efficiency) to end surface  5   a  of optical transmission member  5  and detection device  8 , and the position of the condensing point of the incident light on optical transmission member  5  and detection device  8 . As a result, optical module  1  can be readily manufactured by moderating the dimensional accuracy of optical receptacle  2  while maintaining the optical performance. 
     It is to be noted that a reflection film composed of a thin film of a metal having a high light reflectance (such as Al, Ag and Au) or the like may be formed on reflecting surface  14  and on division reflection surface  18  as necessary. In the case where reduction of the number of components is required to be prioritized, it is preferable to employ the configuration utilizing only total reflection as described above. 
     In addition, from the standpoint of simplifying the design and improving the stability of the light coupling efficiency, it is preferable to form transmission surface parts  191  having widths equal to each other in a direction orthogonal to the longitudinal direction and disposed at even intervals in the dividing direction. 
     In the following, other embodiments, examples and so forth of the present invention will be described. 
     (Modification) 
     Next, modifications of the present embodiment will be described with reference to  FIG. 9  to  FIG. 12 .  FIG. 9  is a sectional view illustrating a configuration of optical module  1  according to a modification of Embodiment 1.  FIG. 10  is a plan view of optical receptacle  2  according to the modification of Embodiment 1.  FIG. 11  is a bottom view of optical receptacle  2  according to the modification of Embodiment 1.  FIG. 12  is a right side view of optical receptacle  2  according to the modification of Embodiment 1 
     Optical module  1  and optical receptacle  2  are of a lens array type in the present modification. In addition, optical module  1  and optical receptacle  2  of the present modification have a configuration for multichannel light transmission performed with monitoring, in addition to the configurations of the main part of optical module  1  and optical receptacle  2  illustrated in  FIG. 1  to  FIG. 5 . 
     A plurality of (twelve) light emitting elements  7  and detection devices  8  according to the present modification are laid out in the depth direction as seen in  FIG. 9  in photoelectric conversion device  3 . In addition, optical transmission members  5  are laid out in the direction in which light emitting element  7  and detection device  8  are laid out, and the number of optical transmission members  5  is equal to that of light emitting element  7  and detection device  8 . It is to be noted that, in  FIG. 9 , each optical transmission member  5  is housed in multicore collective connector  29  and attached on optical receptacle  2  with a publicly known attaching means. 
     Further, in accordance with the configurations of photoelectric conversion device  3  and optical transmission member  5 , optical receptacle  2  has a large dimension in the depth direction as seen in  FIG. 9  in comparison with the basic configuration such that the light path between each light emitting element  7  and each optical transmission member  5 , and the light path between each light emitting element  7  and each detection device  8  can be formed. To be more specific, first to third surfaces S 1  to S 3 , reflecting surface  14  and light separation part  17  are formed in a large size in the depth direction as seen in  FIG. 6  such that the light path of laser light La can be formed for each light emitting element  7 . In addition, first to third optical surfaces  11  to  13  are formed at respective positions corresponding to light emitting element  7 , end surface  5   a  of optical transmission member  5  and detection device  8 , and the number of first to third optical surfaces  11  to  13  are equal to that of light emitting element  7 , optical transmission member  5  and detection device  8 , respectively. 
     With the optical module of the modification of Embodiment 1, laser light La of each light emitting element  7  can be separated into signal light Lc and monitor light M for each light emitting element  7  at light separation part  17 . In addition, since the spot shape illustrated in  FIG. 5A  can be obtained for each signal light Lc, multichannel light transmission performed with monitoring can be simply and properly performed. 
     EXAMPLE 1 
     Next, as an example of the present embodiment, example configurations  1  and  2  of light separation part  17  will be described. 
       FIG. 13A  and  FIG. 13B  illustrate example configuration  1  of light separation part  17  in an example of Embodiment 1. As illustrated in  FIG. 13A , in example configuration  1  of light separation part  17 , the inclination angle of reflecting surface part  181  is approximately 45 degrees clockwise relative to first surface S 1 . In addition, transmission surface part  191  is formed to be orthogonal to first surface S 1 . Further, dimension a of reflecting surface part  181  in the direction orthogonal to first surface S 1  and dimension b of transmission surface part  191  in that direction are set such that the ratio of a:b is 1:1. 
     As illustrated in  FIG. 13B , in this case, in the pair of reflecting surface part  181  and transmission surface part  191  adjacent to each other, each of the light reflectance and the light transmittance can be set to 50%. 
       FIG. 14A  and  FIG. 14B  illustrate example configuration  2  of light separation part  17  in the example of Embodiment 1. As illustrated in  FIG. 14A , in example configuration  2  of light separation part  17 , the inclination angle of reflecting surface part  181  is approximately 45 degrees clockwise relative to first surface S 1  as in  FIG. 13A . In addition, transmission surface part  191  is formed to be orthogonal to first surface S 1 . Further, dimension a of reflecting surface part  181  in the direction orthogonal to first surface S 1  and dimension b of transmission surface part  191  in that direction are set such that the ratio of a:b is 1:3. 
     As illustrated in  FIG. 14B , in this case, in the pair of reflecting surface part  181  and transmission surface part  191  adjacent to each other, the light reflectance and the light transmittance can be set to 25% and 75%, respectively. 
     [Embodiment2] 
     An optical receptacle and an optical module having the optical receptacle according to Embodiment 2 will be described with reference to  FIG. 15  to  FIG. 17B , mainly for configurations different from Embodiment 1.  FIG. 15  illustrates a configuration of light separation part  17  according to Embodiment 2 of the present invention.  FIG. 16A  and  FIG. 16B  illustrate example configuration  1  of light separation part  17  in the example of Embodiment 2.  FIG. 17A  and  FIG. 17B  illustrate example configuration  2  of light separation part  17  in the example of Embodiment 2. 
     As illustrated in  FIG. 15 , division reflection surface  18  in Embodiment 2 is divided in the direction orthogonal to first surface S 1  (vertical direction in  FIG. 15 ). 
     In addition, in Embodiment 2, transmission surface part  191  is continuously connected to adjacent reflecting surface part  181  on first surface S 1  side, and is continuously connected to adjacent reflecting surface part  181  on second surface S 2  side. 
     Other configurations and applicable modifications are identical to those of Embodiment 1, and therefore the detailed description thereof will be omitted. 
     With the optical module according to Embodiment 2, by continuously connecting reflecting surface part  181  and transmission surface part  191 , light separation part  17  can be composed with only an optically required surface (step surface  20  of Embodiment 1 can be omitted). Thus, when optical receptacle  2  is molded with resin with a metal mold, the contact area of light separation part  17  and the metal mold can be reduced, and favorable releasability can be ensured. In addition, the size of light separation part  17  in the transmission direction of signal light Lc can be reduced. 
     EXAMPLE 2 
     Next, as the example of Embodiment 2, example configurations  1  and  2  of light separation part  17  will be described. 
     As illustrated in  FIG. 16A , in example configuration  1  of light separation part  17 , the inclination angle of reflecting surface part  181  is approximately 45 degrees clockwise relative to first surface S 1 . In addition, transmission surface part  191  is formed to be orthogonal to first surface S 1 . Further, dimension a of reflecting surface part  181  in the direction orthogonal to first surface S 1  and dimension b of transmission surface part  191  in that direction are formed such that the ratio of a:b is 1:1. 
     As illustrated in  FIG. 16B , in this case, in the pair of reflecting surface part  181  and transmission surface part  191  adjacent to each other, each of the light reflectance and the light transmittance can be set to 50%. 
     As illustrated in  FIG. 17A , in example configuration  2  of light separation part  17 , the inclination angle of reflecting surface part  181  is approximately 45 degrees clockwise relative to first surface S 1  as in  FIG. 16A . In addition, transmission surface part  191  is formed to be orthogonal to first surface S 1 . Further, dimension a of reflecting surface part  181  in the direction orthogonal to first surface S 1  and dimension b of transmission surface part  191  in that direction are formed such that the ratio of a:b is 1:3. 
     As illustrated in  FIG. 17B , in this case, in the pair of reflecting surface part  181  and transmission surface part  191  adjacent to each other, the light reflectance and the light transmittance can be set to 25%, and 75%, respectively. 
     [Embodiment 3] 
     Next, an optical receptacle and an optical module having the optical receptacle according to Embodiment 3 of the present invention will be described with reference to  FIG. 18A ,  FIG. 18B  and  FIG. 19 , mainly for configurations different from Embodiment 1.  FIG. 18A  and  FIG. 18B  illustrate a configuration of light separation part  17  of Embodiment 3.  FIG. 19  illustrates a configuration of third recess  16  of a modification of Embodiment 3. 
     In the present embodiment, the dividing direction of division reflection surface  18  is a direction orthogonal to the inclination direction of division reflection surface  18  (second inclination angle direction) and the surface normal direction as illustrated in a longitudinal sectional view of  FIG. 18A  and a left side view of  FIG. 18B . 
     As illustrated in  FIG. 18A  and  FIG. 18B , division reflection surface  18  of the present embodiment includes a plurality of reflecting surface parts  181  extending in the inclination direction. 
     In addition, division transmission surface  19  includes a plurality of transmission surface parts  191  extending in the direction orthogonal to first surface S 1  and disposed in a direction orthogonal to the incident direction of signal light Lc. 
     In addition, step surface  20  parallel to the incident direction of laser light La of light emitting element  7  on light separation part  17  is formed between transmission surface part  191  and reflecting surface part  181  adjacent to transmission surface part  191 . 
     While division transmission surface  19  is formed at the position same as the left end portion of division reflection surface  18  as illustrated in  FIG. 18A  and  FIG. 18B , division transmission surface  19  may be formed at the position same as the right end part of division reflection surface  18  as illustrated in  FIG. 19 . 
     Other configurations and applicable modifications are identical to those of Embodiment 1, and therefore the detailed description thereof will be omitted. 
     With the optical module according to Embodiment 3, reflecting surface parts  181  can be disposed on one inclined plane, and transmission surface parts  191  can be disposed on one perpendicular plane, and thus the ease of design is increased. In addition, with the optical module according to Embodiment 3, the influence of step surface  20  on the optical performance can be reduced as much as possible since step surface  20  is parallel to the light path. 
     [Embodiment 4] 
     Next, optical receptacle  2  and optical module  1  having optical receptacle  2  according to Embodiment 4 of the present invention will be described with reference to  FIG. 20  to  FIG. 29B , mainly for configurations different from Embodiment 1.  FIG. 20  illustrates a configuration of optical module  1  according to Embodiment 4.  FIG. 22  illustrates an intensity distribution of signal light at an end surface of optical transmission member  5  in Embodiment 4. 
     As illustrated in  FIG. 20 , in the present embodiment, first optical surface  11  converges laser light La to converging light other than collimate light and outputs the light toward reflecting surface  14  instead of collimating the laser light La as in Embodiment 1. 
     To be more specific, in the configuration illustrated in  FIG. 20 , first optical surface  11  converts laser light La reached from light emitting element  7  into converging light whose light flux diameter gradually increases as it travels forward in the travelling direction. Such a configuration of the present embodiment may be achieved by, for example, reducing the positive power of first optical surface  11  in comparison with the configuration of Embodiment 1. 
       FIG. 21A  to  FIG. 21C  illustrate simulations of the beam spot shape of signal light Lc at different positions on the light path of signal light Lc in the configuration of the present embodiment. To be more specific,  FIG. 21A  illustrates a spot shape of signal light Lc on plane Sa which is virtually provided at a position immediately after transmission surface  21  on the light path in  FIG. 20 . In addition,  FIG. 21B  illustrates the spot shape of signal light Lc on plane Sb which is virtually provided at a position immediately before second optical surface  12  on the light path in  FIG. 20 . Further,  FIG. 21C  illustrates the spot shape of signal light Lc on end surface  5   a  of optical transmission member  5 . 
     As illustrated in  FIG. 21A  to  FIG. 21C , in the present embodiment, the spot shape of signal light Lc clearly sectioned in a belt shape reflecting division transmission surface  19  at a timing immediately after division ( FIG. 21A ) is deformed such that the width of the belts decreases as it travels forward (optical transmission member  5  side) ( FIG. 21B ), and finally the shape becomes a completely single circle spot having no division on end surface  5   a  of optical transmission member  5  ( FIG. 21C ). This is because of the configuration in which first optical surface  11  convers laser light La into converging light (non-collimate light) whose diameter increases as it advances. 
     In addition, since the above-mentioned non-collimate light is employed in the present embodiment, the intensity distribution of signal light Lc at end surface  5   a  of optical transmission member  5  can be set to a shape whose intensity gradually decreases from the central axis side (maximum intensity side) toward the periphery side as illustrated in  FIG. 22 . Such an intensity distribution has a shape substantially similar to that of the intensity distribution of laser light La at a timing before separation at light separation part  17  (the timing includes the timing when the light is emitted from light emitting element  7 ). 
     With the above-mentioned configuration of the present embodiment, the coupling efficiency can be further improved, and in addition, reduction in light coupling efficiency due to positional displacement in the radial direction of optical transmission member  5  can be further effectively reduced in comparison with Embodiment 1. Further, with uniformization of light intensity, radiation loss (bending loss) in the case where optical transmission member  5  is bent when in use can be reduced. Thus, light transmission performed with monitoring can be further properly performed. 
     In addition, according to the present embodiment, the diameter of signal light Lc can be increased along with the advancement of the light, and therefore, even when foreign matters or scratches exist on second optical surface  12 , the area occupancy of foreign matters/scratches with respect to the light spot of signal light Lc on second optical surface  12  can be reduced. Thus, the influence of foreign matters/scratches of second optical surface  12  on the coupling efficiency can be effectively reduced. 
     It is to be noted that the present embodiment includes various modifications described below. 
     (Modification  1 ) 
     For example, as illustrated in the sectional view of  FIG. 23A  and the right side view of  FIG. 23B , non-collimate light similar to the non-collimate light illustrated in  FIG. 20  may be applied in optical module  1  of an lens array type having a plurality of first optical surfaces  11 , a plurality of second optical surfaces  12  and a plurality of third optical surfaces  13 . 
     It is to be noted that the specific configuration of the present modification is identical to that of the modification of Embodiment 1 (see  FIG. 9  to  FIG. 12 ) except for the shape of first optical surface  11 , and therefore the description thereof will be omitted. 
     With the present modification, signal light Lc of each optical transmission member  5  based on laser light La emitted from each of light emitting elements  7  has the spot shape illustrated in  FIG. 21A  to  FIG. 21C . Thus, in comparison with the modification of Embodiment 1, multichannel light transmission performed with monitoring can be further appropriately performed. 
     (Modification  2 ) 
       FIG. 24  illustrates a configuration of an optical module according to modification  2  of Embodiment 4. In addition, as illustrated in  FIG. 24 , in optical module  1  according to modification  2 , laser light La emitted from light emitting element  7  and incident on first optical surface  11  may be converging light (non-collimate light) whose light flux diameter gradually decreases as it travels forward in the travelling direction. Laser light La incident on first optical surface  11  may be set to the converging light whose light flux diameter gradually decreases as it travels forward in the travelling direction by increasing the positive power of first optical surface  11  in Embodiment 1 or the like. 
       FIG. 25A  to  FIG. 25C  illustrate simulations of the beam spot shape of signal light Lc at different positions on the light path of signal light Lc in modifications  1  and  2 .  FIG. 25A  illustrates a spot shape on provided plane Sa virtually provided at a position immediately after transmission surface  21  on the light path in  FIG. 24 ,  FIG. 25B  illustrates a spot shape on plane Sb which is virtually provided at a position immediately before second optical surface  12  on the light path in  FIG. 24 , and  FIG. 25C  illustrates a spot shape on end surface  5   a  of optical transmission member  5 . 
     As illustrated in  FIG. 25A  to  FIG. 25C , also in modifications  1  and  2 , the spot shape of signal light Lc sectioned in a belt shape at a position immediately after division transmission surface  19  can be finally set to a completely single circle spot on end surface  5   a  of optical transmission member  5  as with optical module  1  according to Embodiment 1 illustrated in  FIG. 21A  to  FIG. 21C . 
     As described above, as with the configuration of  FIG. 20 , optical module  1  according to modifications  1  and  2  can improve the intensity distribution of signal light Lc at end surface  5   a  of optical transmission member  5 , and therefore can further properly perform light transmission performed with monitoring in comparison with Embodiment 1. 
     (Modification  3 ) 
       FIG. 26A  is a sectional view illustrating a configuration of an optical module according to modification  3 of Embodiment 4, and  FIG. 26B  is a right side view thereof. Further, the non-collimate light (converging light whose diameter is reduced as it advances) described in modification  2  may be adopted in the configuration of a lens array type illustrated in the sectional view of  FIG. 26A  and the right side view of  FIG. 26B . 
     With the present modification, signal light Lc of each optical transmission member  5  based on laser light La emitted from each of light emitting elements  7  has the spot shape illustrated in  FIG. 25A  to  FIG. 25C . Thus, in comparison with the modification of Embodiment 1, multichannel light transmission performed with monitoring can be further appropriately performed. 
     (Modification  4 ) 
     In addition, since the non-collimate light described in the second modification is effectively converged before the light reaches second optical surface  12 , the light is in some situations not required to be converged at one time for the coupling to end surface  5   a  of optical transmission member  5  at second optical surface  12 . In this case, it is not necessary to intentionally apply a large power to second optical surface  12 , and therefore the surface shape can be simplified (or can be set to a nearly planar shape). The configuration of the present modification is achieved by developing the above-mentioned approach.  FIG. 27  is a sectional view illustrating a configuration of an optical module according to modification  4  of Embodiment 4. 
     That is, as illustrated in  FIG. 27 , in the configuration of the present modification, a non-collimate light whose diameter is reduced as it advances is applied as with modification  2 , and third surface S 3  is formed as a plane having no second optical surface  12 . 
     Here,  FIG. 28A  to  FIG. 28C  illustrate simulations of the beam spot shape of signal light Lc at different positions on the light path of signal light Lc in the above-mentioned configuration of the present modification. To be more specific,  FIG. 28A  illustrates a spot shape plane Sa virtually provided at a position immediately after transmission surface  21  on the light path in  FIG. 27 ,  FIG. 28B  illustrates a spot shape on plane Sb virtually provided at a position immediately before third surface S 3  on the light path in  FIG. 27 , and  FIG. 28C  illustrates a spot shape on end surface  5   a  of optical transmission member  5 . 
     As illustrated in  FIG. 28A  to  FIG. 28C , also in the present modification, the spot shape of signal light Lc sectioned in a belt shape at a position immediately after division transmission surface  19  may be finally set to a completely single circle spot on end surface  5   a  of optical transmission member  5  as in  FIG. 21A  to  FIG. 21C . 
     With the present modification, since second optical surface  12  is not required, light transmission performed with monitoring can be further properly performed in comparison with Embodiment 1, and cost can be reduced by simplifying the shape. 
     (Modification  5 ) 
       FIG. 29A  is a sectional view illustrating a configuration of an optical module according to modification  5  of Embodiment 4, and  FIG. 29B  is a right side view thereof. As illustrated in  FIG. 29A  and  FIG. 29B , optical module  1  according to modification  5  of Embodiment 4 may have a configuration of a lens array type in which second optical surface  12  described in the fourth modification is not provided. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors in so far as they are within the scope of the appended claims or the equivalents thereof. 
     For example, the collimate light and the non-collimate light described in the embodiments may be achieved by adjusting the emission angle of laser light La by light emitting element  7  or the like in place of, or in addition to the surface shape of first optical surface  11 . 
     (Modification  6 ) 
     The present modification includes light separation part  330  having another configuration as the light separation part. 
       FIG. 30A  to  FIG. 31B  illustrate a configuration of light separation part  330 . FIG.  30 A is a perspective view of light separation part  330 , and  FIG. 30B  is a plan view of light separation part  330 .  FIG. 31A  is a partially enlarged sectional view of light separation part  330  having a configuration similar to that illustrated in  FIG. 4 , and  FIG. 31B  is a partially enlarged sectional view illustrating a light path of light separation part  330 . In  FIG. 31B , the hatching of the cross-section of optical receptacle  2  is omitted to illustrate a light path in optical receptacle  2 . 
     As illustrated in  FIG. 30A  to  FIG. 31B , light separation part  330  includes a plurality of division reflection surfaces  331 , a plurality of division transmission surfaces  332 , a plurality of division step surfaces  333 , and a plurality of end surfaces  334 . Division reflection surface  331 , and division transmission surface  332  and division step surface  333  are alternately disposed in the first direction and the second direction orthogonal to the first direction so as to form a matrix shape. Here, the “first direction” is the inclination direction of division reflection surface  331  described later (see arrow D 1  illustrated in  FIG. 30A  and  FIG. 30B ). In addition, the “second direction” is a direction along division reflection surface  331  and orthogonal to the first direction (see arrow D 2  illustrated in  FIG. 30A  and  FIG. 30B ). 
     Division reflection surface  331  is an inclined surface with respect to the optical axis of light La reflected by reflecting surface  14 . Division reflection surface  331  is tilted toward optical transmission member  5  from the top surface to the bottom surface of optical receptacle  2 . In the present embodiment, the inclination angle of division reflection surface  331  is 45 degrees to the optical axis of light La reflected by reflecting surface  14 . A plurality of division reflection surfaces  331  are disposed on one plane. In addition, division reflection surfaces  331  are disposed in the first direction and the second direction at predetermined intervals. Division transmission surface  332  and division step surface  333  are disposed between division reflection surfaces  331  adjacent to each other in the first direction. On the other hand, division transmission surface  332 , division step surface  333  and a pair of end surfaces  334  are disposed between division reflection surfaces  331  adjacent to each other in the second direction. The distances between division reflection surfaces  331  in the first direction and the second direction are not limited. In the present embodiment, the distances between the division reflection surfaces  331  in the first direction and the second direction are equal to each other. 
     Division transmission surface  332  is a surface which is formed at a position different from division reflection surface  331 , and is perpendicular to the optical axis of light La reflected by reflecting surface  14 . Division transmission surfaces  332  are disposed in the first direction and the second direction at predetermined intervals. Division transmission surfaces  332  are parallel to each other in the first direction and are disposed on one plane in the second direction. 
     Division step surface  333  is a surface which is parallel to the optical axis of light La reflected by reflecting surface  14 , and connects division reflection surface  331  and division transmission surface  332 . Division step surfaces  333  are disposed in the first direction and the second direction at predetermined intervals. Division step surfaces  333  are parallel to each other in the first direction, and disposed on one plane in the second direction. 
     End surface  334  is a surface which is parallel to the optical axis of light La reflected by reflecting surface  14  and is perpendicular to division transmission surface  332  and division step surface  333 . End surface  334  is disposed at both ends of division transmission surface  332  and division step surface  333  in the second direction, and connects the both ends of division transmission surface  332  and division step surface  333  with division reflection surface  331 . A plurality of end surfaces  334  are disposed on one plane in the first direction, and are parallel to each other in the second direction. 
     A ridgeline is formed between division transmission surface  332  and division step surface  333 . The ridgelines adjacent to each other in the first direction are parallel to each other. In addition, a plurality of ridgelines adjacent to each other in the second direction are disposed on the same straight line. In the present embodiment, the smaller angle of the angles between division transmission surface  332  and division step surface  333  is 90 degrees. In addition, the smaller angle of the angles between division transmission surface  332  and division reflection surface  331  is 135 degrees. In addition, the smaller angle of the angles between division step surface  333  and division reflection surface  331  is 135 degrees. That is, division transmission surface  332  and division step surface  333  are formed in the same rectangular. 
     As illustrated in  FIG. 31B , light La reflected by reflecting surface  14  is internally incident on division reflection surface  331  at an incident angle greater than the critical angle. Division reflection surface  331  reflects incident light La toward third surface S 3  to generate monitor light M. On the other hand, division transmission surface  332  allows light La reflected by reflecting surface  14  to pass therethrough, and generates signal light Lc directed toward end surface  5   a  of optical transmission member  5 . Signal light Lc is emitted to second recess  15 . At this time, division transmission surface  332  is a surface perpendicular to light La and therefore signal light Lc is not refracted. It is to be noted that division step surface  333  and end surface  334  are parallel to the incident direction of light La, and therefore light La is not incident on division step surface  333  and end surface  334 . 
     The light quantity ratio of signal light Lc and monitor light M generated at light separation part  330  is not limited. The light quantity ratio of signal light Lc and monitor light M is proportional to the area ratio of division transmission surface  332  and division reflection surface  331  with respect to laser light La incident on light separation part  330 . For example, it is assumed that the ratio of dimension d 1  of division transmission surface  332  to dimension d 2  of division reflection surface  331  in the direction parallel to division transmission surface  332  in the cross-section illustrated in  FIG. 31B  is 1:1. In this case, signal light Lc of 50% and monitor light M of 50% are generated from the light of 100% incident on light separation part  330 . 
     When division reflection surface  331  and division transmission surface  332  are alternately disposed in the first direction and the second direction in the above-mentioned manner, the entire spot shape of signal light Lc is uniformly sectioned into a matrix pattern by reflecting division transmission surface  332  at a timing immediately after division although not illustrated in the drawings, and thus the influence of the angle intensity distribution of light emitting element  7  is reduced in comparison with the case where the spot shape is sectioned into a lateral striped pattern as illustrated in  FIG. 21A , for example. 
     As described above, in optical receptacle  2  according to the present embodiment, laser light La emitted from light emitting element  7  is reflected by reflecting surface  14  along the surface of semiconductor substrate  6 , and is separated into monitor light M and signal light Lc through reflection on division reflection surface  331  and transmission on division transmission surface  332 . Monitor light M is emitted from second surface S 2  toward detection device  8 , and signal light Lc is emitted from third surface S 3  toward end surface  5   a  of optical transmission member  5  without changing the travelling direction. Thus, optical receptacle  2  can set the direction of signal light Lc at end surface  5   a  of optical transmission member  5  to a direction along semiconductor substrate  6  while acquiring monitor light M for monitoring laser light La emitted from light emitting element  7 . In addition, optical receptacle  2  is not easily influenced by the angle intensity distribution of light emitting element  7 . 
     This application is entitled to and claims the benefit of Japanese Patent Application No. 2014-055592 filed on Mar. 18, 2014, the disclosure each of which including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
     INDUSTRIAL APPLICABILITY 
     The optical receptacle and the optical module according to the embodiments and so forth of the present invention are suitable for optical communications using an optical transmission member. 
     REFERENCE SIGNS LIST 
     
         
           1  Optical module 
           2  Optical receptacle 
           3  Photoelectric conversion device 
           4  Optical transmission member attaching portion 
           5  Optical transmission member 
           6  Semiconductor substrate 
           7  Light emitting element 
           8  Detection device 
           9  Ferrule 
           10  First recess 
           11  First optical surface 
           12  Second optical surface 
           13  Third optical surface 
           14  Reflecting surface 
           15  Second recess 
           16  Third recess 
           17 ,  330  Light separation part 
           18 ,  331  Division reflection surface 
           19 ,  332  Division transmission surface 
           20  Step surface 
           21  Transmission surface 
           29  Connector 
           181  Reflecting surface part 
           191  Transmission surface part 
           333  Division step surface 
           334  End surface 
           2   a  Lower end surface 
           2   b  Upper end surface 
           2   c  Left end surface 
           2   d  Right end surface 
           2   e  Front end surface 
           2   f  Rear end surface 
           5   a  End surface 
         La Collimate light (laser light) 
         Lc Signal light 
         M Monitor light 
         OA optical axis (central axis) 
         RM Reflection monitor light 
         S 1  First surface 
         S 2  Second surface 
         S 3  Third surface 
         Sa, Sb Plane