JP5090383B2 - Optical module - Google Patents

Description

  The present invention relates to an optical module that is used as a light-emitting module that has a light-emitting element and provides an optical signal to an optical fiber, or that is used as a light-receiving module that includes a light-receiving element that receives an optical signal propagated through the optical fiber. In particular, the present invention relates to an optical module provided with a light guide member that changes the direction of light.

  In an optical module such as a light emitting module or a light receiving module, a light emitting element or a light receiving element is provided in a housing, and an end of the optical fiber is held in the housing, and light is transmitted between the light emitting element or the light receiving element and the optical fiber. You can give and receive.

  This type of optical module may be used with the axial direction of the optical fiber orthogonal or oblique to the direction of the optical axis of the light emitting element or light receiving element. In this case, it is necessary to bend and pull out the optical fiber whose end is held in the housing in front of the housing. However, since there is a limit to reducing the radius of curvature when the optical fiber is bent, the optical fiber cannot be bent when the space in front of the housing is narrow.

  The following Patent Documents 1, 2, and 3 disclose optical modules having an optical path changing function that makes the axial direction of an optical fiber orthogonal to the direction of the optical axis of a light emitting element or a light receiving element.

  In the optical module described in Patent Document 1, the lower surface of the plate-shaped optical waveguide is opposed to the position facing the light emitting semiconductor laser. A core having a high refractive index is inserted in the optical waveguide, and the optical fiber is held by the optical waveguide such that the end face faces the end face of the core. The end surface of the optical waveguide is an inclined surface, and the core extends to the inclined surface. Light emitted from the light emitting semiconductor laser enters the optical waveguide from the lower surface, is reflected by the inclined surface, enters the core, and is further applied to the optical fiber.

  In the optical module described in Patent Document 2, the light receiving element faces the lower surface of the plate-shaped optical coupling component. An optical fiber is held inside the optical coupling member, and the end face of the optical coupling member is a concave mirror portion facing both the light receiving element and the end face of the optical fiber. The light emitted from the core of the optical fiber is reflected by the concave mirror and given to the light receiving element.

  Patent Document 3 discloses an optical element having an optical path changing function. This optical element has a light incident surface and a light exit surface, which are flat surfaces oriented at right angles to each other, and a curved optical path changing surface that extends between the light entrance surface and the light exit surface. The light projecting element faces the light incident surface, and the end surface of the core of the optical fiber faces the light emitting surface. Light emitted from the light projecting element and incident on the inside of the optical element from the light incident surface is converted into an optical path. The light is reflected from the surface and given to the core of the optical fiber from the light emitting surface.

JP 2007-133160 A JP 2001-51162 A JP 2003-307603 A

  In the optical waveguide disclosed in Patent Document 1, a clad layer having a refractive index lower than that of the core appears on the lower surface facing the light emitting semiconductor laser. Therefore, the light incident on the cladding layer is easily reflected and returned at the interface with the core, and not only the light utilization efficiency is lowered, but the light reflected by the core returns to the light emitting semiconductor laser, and the light emitting semiconductor Noise is likely to be superimposed on the optical signal emitted from the. In addition, it is necessary to position the distance between the inclined surface of the end face of the optical waveguide and the light emitting semiconductor laser and the facing position with extremely high accuracy, and the assembly work is complicated.

  In the device described in Patent Document 2, the light emitted from the optical fiber can be condensed by the concave mirror and provided to the light receiving element. However, when the light emitting element is used, the light emitted from the light emitting element is used. It is difficult to focus and enter the optical fiber core. Moreover, since it is necessary to adjust the light receiving element to the focal position of the concave mirror portion with high accuracy, the assembly work is complicated.

  Since the optical element described in Patent Document 3 is formed in a fan shape with a light incident surface, a light emitting surface, and an optical path conversion surface, the optical element becomes a large component and is mounted on a small optical module. It ’s hard. Further, since the light incident surface and the optical fiber light exit surface facing the light projecting element are elongated, it is determined which position of the light incident surface and the light exit surface should be opposed to each other. Therefore, adjustment work such as searching for a place where the light transmission efficiency is maximized while moving the light projecting element and the optical fiber is necessary, and the assembly work of the optical module becomes complicated.

  The present invention solves the above-described conventional problems, and can increase the light transmission efficiency between the light-emitting element or the light-receiving element and the optical fiber, and can easily position the mounting position of the light guide member. The purpose is to provide.

The present invention provides a housing, a light receiving element or a light emitting element provided in the housing, a light guide member made of a translucent material accommodated in the housing, and an end of an optical fiber provided in the housing. In an optical module having a fiber holder,
The light guide member has a first end face facing the light receiving element or the light emitting element and a second end face facing the end face of the optical fiber, and passes through the centroid of the first end face. The first end surface center line orthogonal to the first end surface and the second end surface center line orthogonal to the second end surface through the centroid of the second end surface form an angle of less than 180 degrees. And a curved portion having a curved inner center line passing through the centroid of the cross section is provided between the first end surface and the second end surface,
A housing space is provided in the housing, the light emitting element or the light receiving element is disposed at the bottom of the housing space, and an insertion opening is opened at a position facing the bottom surface. It is characterized by being inserted into the storage space from the insertion port so that the end surface center line of 1 is directed to the bottom, and is positioned and held in the housing.

  In the optical module of the present invention, since the light guide member is provided with a curved portion whose inner center line is a curve, the optical path of light propagating between the first end surface and the second end surface is in a state with little loss. Can be bent with. Further, since the light guide member can be positioned in the housing by being inserted into the storage space from one direction along the center line of the first end surface, the assembling work is easy. Further, since the light guide member is positioned in the housing in the inserted state, the light emitting element or the light receiving element and the light guide member can be opposed to each other at an optimum position, and the optical fiber and the light guide member can be opposed to each other at an optimum position. it can.

  In the present invention, the light guide member is integrally formed with a positioning portion extending in parallel with the first end surface center line, and the positioning portion contacts the inside of the housing, and the light guide member Positioning in a direction toward the bottom and positioning in a direction orthogonal to the direction are performed.

  In this case, according to the present invention, a concave portion or a hole portion is formed in the positioning portion, and a protrusion that fits into the concave portion or the hole portion is formed inside the housing. A structure in which the recess or the hole fits with the protrusion when the first end surface center line is inserted into the storage space so as to face the bottom.

  In the present invention, the light guide member is brought into contact with the interior of the housing by a simple assembling operation in which the light guide member is inserted into the storage space so that the center line of the first end surface is directed toward the bottom portion. Can be positioned at an optimal storage position.

  In the present invention, the distance from the starting end to the positioning portion is the length when the end of the bending portion is the starting end and the total length of the bending portion in the direction orthogonal to the cross section of the end is L. It is preferable that it is 1/8 or more and 3/8 or less of L.

  When the positioning portion is arranged in the above range, the probability that the light propagating inside the light guide member is lost by the positioning portion can be increased.

  In the present invention, it is preferable that a lid for closing the insertion port of the housing is provided, the light guide member is inserted into the storage space, and the light guide member is prevented from being detached by the lid. .

  By providing the lid, the light guide member can be positioned and held in an optimal position in the housing space of the housing.

  Further, in the present invention, the shape of the cross section of the light guide member at the curved portion is a curved surface in which the outer peripheral surface has a curvature in a direction perpendicular to the inner center line, and the inner peripheral surface is It is preferable that there is no curvature in a direction orthogonal to the internal center line.

  If the cross section of the curved portion of the light guide member is formed in the above shape, it is easy to reduce the loss of light propagation inside the curved portion of the light guide member.

  The present invention can reduce the propagation loss of light in the light guide member even when an angle of less than 180 degrees is provided between the optical axis of the light emitting element or the light receiving element and the axis center of the optical fiber. .

  Further, the light guide member can be easily assembled to the housing, and the light guide member can be positioned and held in the housing with high accuracy.

The front view of the optical module of the present invention from the bonding side with the optical fiber, 1 is a cross-sectional view taken along line II-II of the optical fiber shown in FIG. The partial perspective view which shows the detail of the structure of a light guide member and a positioning part, The partial perspective view which shows the detail of the modification of a light guide member and a positioning part, The partial perspective view which shows the detail of the modification of a light guide member and a positioning part, Side view of the light guide member, A diagram showing the relationship between the position of the positioning part and the coupling loss of light, Explanatory drawing which shows the cross-sectional shape of the curved part of a light guide member,

  The optical module 20 shown in FIG. 1 has a common housing 1 and a first module 21 and a second module 22 are integrally formed. One of the first module 21 and the second module 22 is a light emitting module, and the other is a light receiving module. Although FIG. 2 shows the first module 21 in a sectional view, the first module 21 and the second module 22 are different depending on whether a light emitting element or a light receiving element is provided inside. Other than this, the basic structure is the same. Therefore, only the structure of the first module 21 will be described below.

  As shown in FIG. 2, the housing 1 has a base portion 2, and an optical element 3 is mounted on the surface of the base portion 2. When the first module 21 is a light emitting module, the optical element 3 is a light emitting element such as a light emitting diode or a semiconductor laser. When the first module 21 is a light receiving module, the optical element 3 is a photodiode or the like. It is a light receiving element. The base unit 2 is provided with terminals 5 and 5, and the optical element 3 is connected to an external circuit through the terminals 5 and 5.

  A coating layer 4 that covers the optical element 3 is formed on the surface of the base 2, and the coating layer 4 is formed of a synthetic resin material that is a translucent material. For example, the coating layer 4 is made of cyclic polyolefin or the like. The translucent material in the present specification means a transparent or almost transparent material having a total light transmittance of 90% or more.

  In the housing 1, a lower housing part 6 is fixed on the base part 2 so as to accommodate the covering layer 4, and a central housing part 7 is provided on the lower housing part 6. The lower part is inserted into the lower housing part 6 without a gap. Base portions of latch springs 8, 8 formed of a leaf spring material are fixed to the lower housing portion 6, and the latch springs 8, 8 are latched by the central housing portion 7, so that the central housing portion 7 is It is fixed to the lower housing part 6.

  An upper housing portion 9 that is a lid is fixed to the upper portion of the central housing portion 7. A storage space 7a extending in the vertical direction (Y1-Y2 direction) is formed inside the central housing portion 7, and a positioning space 9a is formed inside the upper housing portion 9. The optical element 3 faces the opening of the bottom portion 7b on the Y2 side of the storage space 7a. A light guide member 10 is housed in the housing space 7a and the positioning space 9a.

  In a state where the upper housing part 9 is not fixed to the central housing part 7, the light guide member 10 is inserted in the Y1 direction from the insertion port 7c on the Y1 side of the storage space 7a of the central housing part 7, so that the light guide member 10 is It is positioned inside the storage space 7a. After that, the upper housing part 9 as a lid is fixed on the central housing part 7 by means such as adhesion or screwing, and at this time, the positioning space 9a in which the upper part of the light guide member 10 is formed in the upper housing part 9 And is further positioned.

  The light guide member 10 is housed inside, and the lower portion of the central housing portion 7 is inserted into the lower housing portion 6 in a state where the central housing portion 7 and the upper housing portion 9 are fixed. At 8, 8, the central housing part 7 is fixed.

  As shown in FIG. 2, a fiber holding portion 7 d that holds the end portion of the optical fiber 23 is integrally formed on the upper portion of the central housing portion 7. The holding hole 7e inside the fiber holding portion 7d communicates with the positioning space 9a inside the upper housing portion 9.

  The light guide member 10 is formed of a synthetic resin material that is a translucent material. The synthetic resin material is, for example, a cyclic polyolefin, and has a refractive index of approximately 1.5, which is equivalent to the core portion of the optical fiber 23. Moreover, it is preferable that the coating layer 4 covering the optical element 3 also has a refractive index equivalent to that of the light guide member 10.

  As shown in FIGS. 2 and 6, the light guide member 10 has a first end surface 11 and a second end surface 12. When the lower part of the central housing part 7 is inserted into the lower housing part 6 and fixed by the latch springs 8, 8, the first light guide member 10 held in the storage space 7 a of the central housing part 7 is provided. The end surface 11 abuts on the upper surface of the coating layer 4, and the first end surface 11 faces the optical element 3. In the state of FIG. 2, the second end face 12 of the light guide member 10 is desired in the holding hole 7e of the fiber holding portion 7d. When the end portion of the optical fiber 23 is held by the fiber holding portion 7d, the end face of the core portion of the optical fiber 23 faces the second end face 12 of the light guide member 10, and preferably abuts on the second end face 12. .

  As shown in FIGS. 2 and 6, a center line that passes through the centroid (center of gravity of the surface) of the first end surface 11 of the light guide member 10 and is orthogonal to the first end surface 11 is defined as a first end surface center line O1. The first end face center line O1 and the second end face center line O2 when the center line orthogonal to the second end face 12 passing through the centroid of the second end face 12 is defined as the second end face center line O2. Intersect at an angle of less than 180 degrees. In this embodiment, the first end face center line O1 and the second end face center line O2 intersect at an angle of approximately 90 degrees. Therefore, the light path of the light guide member 10 is converted by 90 degrees between the first end surface 11 and the second end surface 12.

  As shown in FIG. 6, in the light guide member 10, a certain range above the first end surface 11 is a straight line portion 13, and in this straight line portion 13, the center line passing through the centroid of the cross section is the first line portion. It coincides with the end face center line O1.

  A range from the upper end 13 a of the linear portion 13 to the second end surface 12 is the curved portion 14. In the bending portion 14, the internal center line O3 connecting the centroids of the cross section is curved. In the embodiment shown in FIG. 6, the inner center line O3 coincides with an arc having a curvature with a constant radius R. The length of the curved portion 14 is set so that the inner center line O3 corresponds to a quarter of a circle having a radius R. The shape of the curved portion 14 is not limited to the shape in which the inner center line O3 coincides with an accurate circular arc, and may be a part of an elliptical or elliptical arc, for example.

  The light guide member 10 shown in FIG. 6 has a straight portion 13 shorter than that shown in FIG. 2, but the length of the straight portion 13 is arbitrary. Or the linear part 13 is not provided, but the 1st end surface 11 may be located in the edge part (part shown with the code | symbol 13a) of the curved part 14. FIG. In the light guide member 10 shown in FIG. 6, the inner center line O3 is in contact with the second end face center line O2 on the second end face 12, and no linear portion is provided on the first end face 12 side. However, a straight line portion extending rightward in the drawing from the second end face 12 and having a cross-sectional centroid coincident with the second end face center line O2 may be provided.

  FIG. 8 shows a cross section of the curved portion 14 of the light guide member 10. The curved portion 14 has the same cross-sectional shape at any location (however, a location having a positioning portion 15 described later is different).

  The cross-sectional shape of the curved portion 14 shown in FIG. 8 is a straight line in which the inner peripheral surface 14a has no curvature in the left-right direction (X1-X2 direction) orthogonal to the internal center line O3. As shown in FIG. 6, when viewed in the YZ plane, the inner peripheral surface 14a is a cylindrical surface with a radius r that curves in the front-rear direction (Z1-Z2 direction). The center of curvature O0 with the radius r coincides with the center of curvature (radius R) of the internal center line O3.

  As shown in FIG. 8, the cross-sectional shape of the curved portion 14 is a curve in which the outer peripheral surface 14b has a curvature in the left-right direction (X1-X2 direction). In this embodiment, the surface 14b that appears in the cross-section The line is an arc of approximately 180 degrees. Therefore, as shown in FIG. 6, the outer peripheral surface 14b has a curvature in the same direction as the internal center line O3 when viewed in the YZ plane, and when viewed in the cross section of FIG. It is a three-dimensional curved surface having a curvature in the (X1-X2 direction).

  Further, as shown in FIG. 8, in the cross-sectional shape of the curved portion 14, both side surfaces 14c, 14c facing in the left-right direction (X1-X2 direction) are perpendicular to the straight line of the cross section of the inner peripheral surface 14a. Both side surfaces 14c, 14c are flat surfaces facing each other in parallel.

  The cross-sectional shape of the light guide member 10 in the linear portion 13 is the same as the cross-sectional shape of the light guide member 10 in the curved portion 14 shown in FIG. A surface 13b facing forward (Z1 direction) of the straight portion 13 is continuous with the inner peripheral surface 14a of the curved portion 14, and is a flat surface extending in the vertical direction (Y1-Y2 direction). A surface 13c facing the rear side (Z2 direction) of the straight portion 13 is continuous with the outer surface 14b of the curved portion 14, and is a curved surface having a curvature in the left-right direction (X1-X2 direction).

  A positioning portion 15 is formed to protrude integrally with the curved portion 14 of the light guide member 10. As shown in FIG. 3, the side surfaces 15 a and 15 a facing the left and right direction (X1-X2) of the positioning portion 15 are the same plane as the side surfaces 14 c and 14 c of the bending portion 14. As shown in FIG. 6, the front end surface 15b of the positioning portion 15 facing the Z1 direction is a flat surface, and the rear end surface 15c facing away from the front end surface 15b is also a flat surface. The front end face 15b and the rear end face 15c are parallel to each other, and these faces are parallel to the second end face 12 and the first end face center line O1. The lower end surface 15d of the positioning portion 15 is a plane in a direction orthogonal to the first end surface center line O1. The positioning portion 15 has a recess 15e formed upward from the lower end surface 15d. The upper inner bottom surface 15f of the recess 15e is a flat surface parallel to the lower end surface 15d, and the inner side surfaces 15g and 15g are flat surfaces parallel to the both side surfaces 15a and 15a.

  As shown in FIG. 2, the inner surface of the front (Z1 direction) of the storage space 7a formed in the central housing portion 7 is parallel to both the left-right direction (X1-X2 direction) and the vertical direction (Y1-Y2). It is a butting plane 17.

  As shown in FIGS. 2 and 3, an abutting surface 16 a is formed inside the central housing portion 7. The abutting surface 16a is a horizontal flat surface parallel to the upper surface of the base portion 2, and a fitting projection 16b is integrally formed upward on the abutting surface 16a. The upper surface 16c of the fitting protrusion 16b is a flat surface parallel to the abutting surface 16a. The side surfaces 16d and 16d facing the left and right direction (X1-X2 direction) of the fitting protrusion 16b are parallel to each other and extend vertically from the abutting surface 16a.

  As shown in FIG. 3, the inner side surface of the positioning space 9 a formed in the upper housing portion 9 in the left-right direction (X1-X2 direction) has parallel plane portions 9 b and 9 b, and the plane portions 9 b and 9 b The base portion 2 extends perpendicularly to the top surface. The facing interval W2 in the left-right direction (X1-X2 direction) of the flat portions 9b, 9b is substantially the same as the facing interval W1 between the side surfaces 14c, 14c of the curved portion 14 of the light guide member 10.

  As shown in FIG. 2, in the positioning space 9 a formed in the upper housing portion 9, a first facing portion that faces the uppermost end portion (the upper end of the second end surface 12) of the light guide member 10 without a gap. A second facing portion 9d that faces the outer peripheral surface of the light guide member 10 without a gap is formed at a substantially boundary portion between the curved portion 14 and the straight portion 13.

  An assembly process of the first module 21 will be described. The assembly process of the second module 22 is the same as that of the first module 21.

  The light guide member 10 is inserted into the storage space 7a from the insertion port 7c of the central housing part 7 separated from the lower housing part 6. At this time, the internal center line of the linear portion 13 of the light guide member 10, that is, the first end surface center line O1 is linearly inserted toward the bottom portion 7b of the storage space 7a. 3, the lower end surface 15d of the positioning portion 15 shown in FIG. 3 is abutted against the abutting surface 16a in the central housing portion 7, or the upper inner bottom surface 15f of the recess 15e formed in the positioning portion 15 is The position of the light guide member 10 in the Y1 direction is determined by abutting against the upper surface 16c of the fitting protrusion 16b. Further, the fitting protrusion 16b fits in the left-right direction (X1-X2 direction) with almost no gap in the recess 15e of the positioning part 15, and the positioning part 15 is positioned in the left-right direction.

  When the upper housing portion 9 is attached to the central housing portion 7 and fixed by bonding or screwing, the curved portion of the light guide member 10 is placed in the positioning space 9a formed in the upper housing portion 9 as shown in FIG. 14 is fitted so that there is almost no gap in the left-right direction (X1-X2 direction), and the bending portion 14 is positioned so as not to move in the X1-X2 direction. In addition, as shown in FIG. 2, the first facing portion 9 c and the second facing portion 9 d formed inside the upper housing portion 9 are mainly formed on the surface 14 b on the outer peripheral side of the curved portion 14 of the light guide member 10. Abut. Thereby, the light guide member 10 is prevented from coming off from the central housing portion 7, and the vertical direction (Y1-Y2 direction) of the light guide member 10 in the housing 1 is prevented. Moreover, since the light guide member 10 is pushed downward (Y1 direction) and forward (Z1 direction) by the first facing portion 9c and the second facing portion 9d, the front portion of the straight portion 13 of the light guide member 10 is flat. The front surface 13b is abutted against a vertical abutting plane 17 in the storage space 7a of the central housing portion 7, and the light guide member 10 is positioned forward (Z1 direction).

  It should be noted that the storage space 7a of the central housing portion 7 is stored by setting the interval between the inner surfaces facing in the left-right direction (X1-X2 direction) to be substantially the same as the width dimension W1 of the light guide member 10 shown in FIG. The light guide member 10 may be positioned and held in the space 7a with almost no movement in the left-right direction (X1-X2 direction).

  As described above, by inserting the light guide member 10 in the Y1 direction which is one direction into the storage space 7a of the central housing portion 7, the linear portion 13 can be inserted into the storage space 7a and the positioning portion 15 is fitted. It can be fitted with the mating protrusion 16b. Further, the light guide member 10 can be positioned and held so that it does not move inside the housing 1 and is not detached by fixing the upper housing part 9 on the central housing part 7. After that, the lower part of the central housing part 7 is inserted into the lower housing part 6, and the central housing part 7 and the lower housing part 6 are positioned without moving with each other. Fix it. In a state where this assembling process is completed, the first end surface 11 of the light guide member 10 is in close contact with the upper surface of the coating layer 4 without a gap, and the optical element 3 faces the first end surface 11. At this time, the optical axis that is the center line of the light emitting region or the light receiving region of the optical element 3 is set substantially parallel to the first end surface center line O1.

  The optical fiber 23 is provided with a clad around the core portion, and is inserted and held in the holding hole 7e of the fiber holding portion 7d. Alternatively, only the core portion of the optical fiber is inserted and held in the holding hole 7e. When the optical fiber 23 is held in the holding hole 7e, the end surface of the core of the optical fiber 23 comes into close contact with the second end surface 12 of the light guide member 10 without a gap.

  When the first module 21 is used as a light emitting module, light emitted from the optical element 3 enters the light guide member 10 from the first end face 11. The light travels while being reflected at the boundary surface between the light guide member 10 and the external air layer, and is given from the second end surface 12 into the core portion of the optical fiber 23.

  When the first module 21 is used as a light receiving module, the optical element 3 is a light receiving element. An optical signal sent through the core portion of the optical fiber 23 enters the light guide member 10 from the second end face 12, reflects between the light guide member 10 and the outer air layer, and travels. The light exits from the first end face 11 and enters the optical element 3.

  As shown in FIG. 6, when the light incident from the first end surface 11 goes to the second end surface 12, the light hits the outer peripheral surface 14 b of the bending portion 14 and is reflected and directed to the second end surface 12. . Even when light is incident from the second end face 12, the light strikes the outer peripheral surface 14 b of the bending portion 14 and is reflected and directed to the first end face 11. At this time, since the inner center line O3 has a curved shape along the circular arc locus, the bending portion 14 has a 90 degree orientation of light incident from the first end face 11 or light incident from the second end face 12. Therefore, it is difficult to leak light from the outer peripheral surface 14b to the outside, and the coupling loss of light can be reduced.

  As shown in FIG. 8, the cross-sectional shape of the light guide member 10 at the curved portion 14 is such that the inner peripheral surface 14a does not have a curvature in the X1-X2 direction, and the outer peripheral surface 14b is X1-X2. It has a curvature on the side. The internally reflected light r1 reflected by the outer peripheral surface 14b is easily reflected so as to concentrate in the direction of the inner center line O3, and is incident on the inner peripheral surface 14a having no curvature. The angle can be reduced, and leakage of external light from the inner peripheral surface 14a can be easily suppressed.

  Conversely, by keeping the inner surface 14a horizontal in the X1-X2 direction in the cross section, the surface 14a can be easily used as a rotation stopper in the housing 1, and the surface 14a is used for positioning. It becomes easy to use as a surface.

  FIG. 7 is a diagram showing the influence of the positioning portion 15 being formed integrally with the light guide member 10. 7, the first end surface 12 (one end surface of the bending portion 14) is the starting end, and the distance from the starting end to the front end surface 15b of the positioning portion 15 is the second end surface 12 (of the bending portion 14). It is expressed as a distance x in a direction perpendicular to one end face). The vertical axis in FIG. 7 indicates the coupling loss of light.

  When used as a light receiving module (i), the coupling loss means a loss of the amount of light emitted from the first end surface 11 with respect to the amount of light input to the second end surface 12, and is used as the light emitting module (ii). In this case, the coupling loss means a loss of the amount of light emitted from the second end surface 12 with respect to the amount of light input to the first end surface 11.

  In FIG. 6, the length dimension of the bending portion 14 in the direction perpendicular to the second end surface 12 (one end surface of the bending portion 14) starts from the second end surface 12 (one end surface of the bending portion 14). L indicates. L is 8 mm.

  FIG. 7 shows that the coupling loss occurs when the distance x is 1/8 or more and 3/8 or less of L, whether it is used as the light receiving module (i) or the light emitting module (ii). Can be reduced. Moreover, as shown in FIG. 6, since the positioning part 15 is provided in the side close | similar to the 2nd end surface 12 in the curved part 14, the direction used as a light reception module (i) is a light emission module (ii). The coupling loss can be made smaller than when it is used.

  In addition, in order to reduce the coupling loss in the case of the light emitting module, a metal film or a white film may be formed on the front end face 15b of the positioning portion 15, and a means for increasing the light reflectance of the front end face 15b may be provided.

4 and 5 show modifications of the positioning portion provided on the light guide member.
In the positioning portion 115 of the light guide member 110 shown in FIG. 4, the concave portion 115 e opens in the X1-X2 direction. When the recess 115e is fitted into the fitting protrusion of the central housing portion 7, the positioning accuracy of the light guide member 110 in the front-rear direction (Z1-Z2 direction) can be increased.

  In the positioning part 215 of the light guide member 210 shown in FIG. 5, a concave part 215e having a round hole is formed, and the fitting protrusion 216b of the central housing part 7 has a cylindrical shape. By fitting the recess 215e into the fitting protrusion 216b, the light guide member 210 can be easily positioned both in the left-right direction (X1-X2 direction) and in the front-rear direction (Z1-Z2 direction).

  4 and 5, the light guide member is positioned in the housing by inserting the light guide member in the Y2 direction with the first end surface center line O1 facing the housing space of the housing. Is possible.

DESCRIPTION OF SYMBOLS 1 Housing 2 Base part 3 Optical element which is a light emitting element or a light receiving element 4 Cover layer 6 Lower housing part 7 Central housing part 7a Storage space 7b Bottom part 7c Insertion port 7d Fiber holding part 9 Upper housing part (lid body)
9a Positioning space 10 Light guide member 11 First end surface 12 Second end surface 14 Curved portion 15 Positioning portion 15e Recess 23 Optical fibers 110 and 210 Light guide members 115 and 215 Positioning portion O1 First end surface center line O2 Second End face center line O3 Internal center line

Claims (6)

A housing, a light receiving element or a light emitting element provided in the housing, a light guide member made of a translucent material housed in the housing, and a fiber holding part provided in the housing for holding an end of an optical fiber; In an optical module having
The light guide member has a first end face facing the light receiving element or the light emitting element and a second end face facing the end face of the optical fiber, and passes through the centroid of the first end face. The first end surface center line orthogonal to the first end surface and the second end surface center line orthogonal to the second end surface through the centroid of the second end surface form an angle of less than 180 degrees. And a curved portion having a curved inner center line passing through the centroid of the cross section is provided between the first end surface and the second end surface,
A housing space is provided in the housing, the light emitting element or the light receiving element is disposed at the bottom of the housing space, and an insertion opening is opened at a position facing the bottom surface. An optical module, wherein the optical module is inserted into the housing space from the insertion port so that a center line of one end surface faces the bottom, and is positioned and held in the housing.   The light guide member is integrally formed with a positioning portion extending in parallel with the first end surface center line, and the positioning portion is in contact with the inside of the housing and is located on the bottom portion of the light guide member. The optical module according to claim 1, wherein positioning in a direction toward and positioning in a direction orthogonal to the direction are performed.   A concave portion or a hole portion is formed in the positioning portion, and a protrusion that fits into the concave portion or the hole portion is formed inside the housing, and the first end surface center line is positioned on the light guide member. The optical module according to claim 2, wherein the concave portion or the hole is fitted to the protrusion when inserted into the storage space so as to face the bottom.   The distance from the starting end to the positioning portion is 1 / L of the length L, where L is the total length of the bending portion in the direction perpendicular to the cross section of the end portion, with the end portion of the bending portion being the starting end. 4. The optical module according to claim 2, wherein the optical module is 8 or more and 3/8 or less.   The lid according to any one of claims 1 to 4, wherein a lid for closing the insertion port of the housing is provided, the light guide member is inserted into the storage space, and the light guide member is prevented from being detached by the lid. The optical module according to crab.   The cross-sectional shape of the light guide member at the curved portion is a curved surface in which the outer peripheral surface has a curvature in a direction orthogonal to the internal center line, and the inner peripheral surface is orthogonal to the internal center line. The optical module according to claim 1, wherein the optical module does not have a curvature in the direction of the optical module.

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