JP2013045024A - Optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical member capable of accurately monitoring light power of a surface-emitting laser.SOLUTION: The optical member includes: an incident region 11 where light emitted from a light-emitting element is made incident; a branch region Z10 for branching the light made incident from the incident region 11 into a first direction and a second direction; a monitor light emitting region 13 for emitting the light branched into the first direction to the outside; and a communication light emitting region 14 for emitting the light branched into the second direction to the outside. The monitor light emitting region 13 is optically connected to an external optical monitor and the light branched into the first direction is made to reach the monitor light emitting region 13 without changing an optical path to shorten the optical path after branching light for monitoring and accurately monitor light power.

Description

  The present invention relates to an optical member.

  Patent Documents 1 and 2 describe a technique related to an optical member for monitoring the optical power of a surface emitting laser. In the optical unit described in Patent Document 1, a surface emitting laser unit and a light receiving unit that receives a part of laser light emitted from the surface emitting laser unit are mounted on the same plane on a substrate. The laser light emitted from the surface emitting laser unit is incident on the optical member by the collimating lens. The incident laser beam is branched at a branching portion in the optical member. One of the branched lights is reflected by the reflection mirror, then emitted from the optical member, and received by the light receiving unit. Further, in the optical waveguide component described in Patent Document 2, first and second reflecting surfaces are provided that divide incident light in two directions and reflect the incident light. After the light from the light emitting element is incident on the optical waveguide component, it is divided into two by the first and second reflecting surfaces. One of the divided lights is incident on the third reflecting surface through the solid medium. This solid medium is formed so that the cross-sectional area decreases in the traveling direction. The light incident on the third reflecting surface is reflected by the third reflecting surface and received by the light receiving element.

JP 2006-344915 A JP 2004-286895 A

  However, in the optical member described in Patent Document 1 and the optical waveguide component described in Patent Document 2, after the monitoring light is branched from the incident light, the direction of the monitoring light is further reflected by the reflecting surface. It needs to be changed in direction. Therefore, the optical path length from when the monitoring light is branched to when it is optically coupled to the monitoring light receiving element is long. Therefore, the monitoring accuracy is reduced due to transmission loss.

  Accordingly, an object of the present invention is to provide an optical member capable of accurately monitoring optical power.

  The optical member of the present invention is branched in the first direction, an incident region where the light emitted from the light emitting element is incident, a branch region where the light incident from the incident region is branched in the first direction and the second direction, and A first emission region that emits the emitted light to the outside and a second emission region that emits the light branched in the second direction to the outside. The first emission region is optically coupled to an external optical monitor, the second emission region is optically coupled to an external optical waveguide, and the light branched in the first direction is changed in optical path. Without reaching the first emission region. In the optical member of the present invention, the light branched in the first direction in the branch region is branched in the branch region and then coupled to the first emission region without changing the direction. Thereby, the optical path after a branch can be shortened. Therefore, since the optical loss of the monitor light after branching with the communication light can be reduced, the state of the communication light can be accurately monitored.

  In the optical member of the present invention, the incident area, the first emission area, and the second emission area all include a collimator lens. The branch region preferably branches at least a part of the outer periphery of the light collimated by the incident region in the first direction. In this case, the monitor light can be cut out without adversely affecting the quality of the communication light. Since the light incident on the branch region has an intensity distribution so that the light intensity decreases from the emission center toward the outer periphery, the weak light at a portion away from the emission center is cut out for monitoring. Therefore, the influence on communication itself can be reduced.

  In the optical member of the present invention, it is preferable that the optical member is the optical member described above, and the branch region branches the entire outer periphery of the light collimated by the incident region in the first direction. Of the light optically coupled to the optical waveguide from the second emission region, the light passing through the outer periphery of the second emission region has a large incident angle to the optical waveguide and excites higher-order mode light. For this reason, a spot-like intensity distribution is generated by the inter-mode interference of the transmitted light, which becomes a cause of deterioration in transmission quality due to mode speckle noise. However, with the above configuration, light passing through the outer periphery of the second emission region can be removed from the communication light, so that generation of mode speckle noise can be prevented. Therefore, deterioration of transmission quality can be suppressed.

  In the optical member of the present invention, the light emitting element and the light monitor are provided on the same side with respect to the optical member, and the branch region reflects a part of the light incident on the branch region in the first direction. It is preferable to have a reflective surface coupled to one emission region. Furthermore, a deflecting unit that deflects light incident from the incident region to the branch region may be further provided between the incident region and the branch region. In this case, the light emitting element and the optical monitor can be formed on the same surface. Therefore, the entire module can be reduced in size.

  ADVANTAGE OF THE INVENTION According to this invention, the optical member which can monitor optical power accurately can be provided.

It is a perspective view for demonstrating the structure of the optical member which concerns on 1st Embodiment. It is a figure for demonstrating the structure of the optical member which concerns on 1st Embodiment. It is a figure for demonstrating the structure of the optical member which concerns on the 1st modification of 1st Embodiment. It is a figure for demonstrating the structure of the optical member which concerns on the 2nd modification of 1st Embodiment. It is a figure for demonstrating the structure of the optical member which concerns on 2nd Embodiment. It is a figure for demonstrating the structure of the optical member which concerns on the modification of 2nd Embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view illustrating the configuration of the optical member 1 according to the first embodiment. FIG. 2 is a view for explaining the configuration of the optical member 1 according to the first embodiment, and is a cross-sectional view taken along line AA of FIG. As shown in FIGS. 1 and 2, the optical member 1 according to the present embodiment includes an incident region 11, a reflecting surface 12, a monitor light emitting region 13 (first emitting region), and a communication light emitting region 14 (second second). An emission region), a branch region Z10, a light propagation region Z11 (first light propagation region), and a light propagation region Z12 (second light propagation region). A concave portion B1 is provided on the surface of the optical member 1 having the monitor light emitting region 13, and a reflective surface 12 is provided on the bottom of the concave portion B1. In this figure, for the sake of simplicity, the case of a single channel will be described as an example. However, it is possible to construct a multi-channel optical member by integrating the components in parallel.

  The incident area 11 is an area where light emitted from the light emitting element 3 outside the optical member 1 enters. The incident area 11 is preferably a collimating lens, and the light that has passed through the incident area 11 is preferably collimated to light parallel to the direction D1 (z-axis direction of the coordinate system C1).

  The reflecting surface 12 is provided on the path of light collimated in the incident region 11 and incident in the direction D1. The reflecting surface 12 is provided in a shape and size that reflects some of incident light and does not reflect other light. That is, the light that passes through the peripheral portion S11 on the outer periphery of the light S10 out of the incident light is not reflected by the reflecting surface 12, but goes to the light propagation region Z11 extending in the direction D2 (z-axis direction of the coordinate system C1). Propagate. The outer periphery of the light S10 refers to an annular portion having a certain width from the outer peripheral end of the light S10 toward the center. The same applies to the other light. On the other hand, the light passing through the central portion S12 of the light S10 among the incident light is reflected by the reflecting surface 12 and propagates to the light propagation region Z12 extending in the direction D3. The reflective surface 12 may be provided with a reflective material by depositing a metal such as aluminum, or may not be provided with a reflective material. In the case where no reflecting material is provided, light is reflected by the difference in refractive index between a material such as a resin constituting the optical member 1 and the air around the optical member 1. In the latter case, the optical member 1 is preferably formed of a resin having a refractive index of about 1.6.

  The branch region Z10 is a region including the reflecting surface 12 in the optical member 1. The branch region Z10 is a region for branching light incident from the incident region 11 in the direction D2 (first direction) and the direction D3 (second direction). The branch region Z10 is provided with a light propagation region Z11 and a light propagation region Z12 extending in different directions.

  The light propagation region Z11 is a region connected to the branch region Z10, and is in the first direction (in the figure, on the opposite side of the incident direction of the incident region 11. The reverse side and the same side are hereinafter referred to as the optical member 1). For example, in FIG. 1, it extends in the xy plane direction and means both sides of the optical member 1. The light propagation region Z11 is provided on the optical path of light incident from the incident region 11 to the branch region Z10. A monitor light emission region 13 is provided at the end of the light propagation region Z11.

  The light propagation region Z12 is a region connected to the branch region Z10 and extends in the second direction (a direction orthogonal to the incident direction of the incident region 11 in the drawing). Further, a communication light emission region 14 is provided at the end of the light propagation region Z12.

  The monitor light emission region 13 is provided at the end of the light propagation region Z11. The monitor light emitting region 13 is a region where the light branched through the branch region Z10 and passed through the light propagation region Z11 is emitted to the outside as monitor light and optically coupled to the light monitor 4 outside the optical member 1. is there. The monitor light emitting region 13 can be configured by hollowing out the central portion of a normal collimating lens, for example. In addition, the monitor light emission region 13 is preferably provided in the peripheral portion S11 on the outer periphery of the light S10 incident from the incident region 11.

  The communication light emitting area 14 is provided at the end of the light propagation area Z12. The communication light emitting region 14 emits light that has been branched in the branch region Z10 and passed through the light propagation region Z12 as communication light, and is optically coupled to the optical fiber 5 outside the optical member 1. The communication light emitting area 14 is preferably a collimating lens.

  The incident area 11, the reflecting surface 12, the monitor light emission area 13, and the communication light emission area 14 described above can be integrally formed by molding a resin, for example.

  Next, the function of the optical member 1 will be described. Light emitted from the light emitting element 3 enters the optical member 1 in the incident region 11. Then, the light passing through the peripheral portion S11 on the outer periphery of the light S10 incident on the optical member 1 from the incident region 11 proceeds to the light propagation region Z11 extending in the direction D2. The light that has passed through the light propagation region Z11 reaches the monitor light emitting region 13 without changing the optical path, and is optically coupled to the optical monitor 4 through the monitor light emitting region 13. On the other hand, the light passing through the central portion S12 of the light S10 incident on the optical member 1 is reflected by the reflecting surface 12, and the optical path is changed to the light propagation region Z12 extending in the direction D3. The light that has passed through the light propagation region Z12 is optically coupled to the optical fiber (optical waveguide) 5 through the communication light emitting region 14.

  As described above, the optical member 1 branches a part of the light emitted from the light emitting element 3 in the direction optically coupled to the optical monitor 4 and then changes the direction of the optical path without changing the direction of the optical path. 13 is optically coupled to the light monitor 4 and enters the light monitor 4 through the monitor light emission region 13. Therefore, the branched optical path in the optical member 1 optically coupled to the optical monitor 4 is shortened, so that the optical power can be accurately monitored.

  FIG. 3 is a diagram for explaining a first modification of the first embodiment. The optical member 1a according to the first modification of the first embodiment includes an incident area 11a, a reflecting surface 12a, a monitor light emitting area 13a (first emitting area), and a communication light emitting area 14a (second emitting area). , A branch region Z10a, a light propagation region Z11a (first light propagation region) and a light propagation region Z12a (second light propagation region). Here, unlike the light propagation region Z11 and the monitor light emitting region 13 in the optical member 1, the light propagation region Z11a and the monitor light emitting region 13a are peripheral portions corresponding to only a part of the outer periphery of the light S10a incident from the incident region 11a. S11a is provided. Similarly to the optical member 1, the optical member 1a also branches a part of the light emitted from the light emitting element 3 in the direction D2 (z-axis direction of the coordinate system C1), and then monitors without changing the direction of the optical path. It is optically coupled to the light output region 13a and enters the light monitor 4 through the monitor light output region 13a. Therefore, the branched optical path in the optical member 1a optically coupled to the optical monitor 4 is shortened, so that the optical power can be accurately monitored.

  In this case, since the light S10a incident from the incident region 11a has a Gaussian distribution type intensity distribution in which the light intensity decreases from the emission center toward the outer periphery, the monitor light cut out from the light S10a is a peripheral portion away from the emission center. S11a faint light. Therefore, the monitor light can be cut out without giving excessive loss to the communication light, so that the influence on the communication itself can be reduced.

  As shown in FIGS. 1 and 2, the monitor light emission region 13 has a ring shape provided on the peripheral portion S <b> 11 over the entire outer periphery of the light S <b> 10 incident from the incident region 11. Is preferred. At this time, the branch area Z10 branches the entire circumference of the light collimated by the incident area 11 in the direction D2. Also in this case, since the monitor light cut out from the light S10 is weak light in the peripheral part S11 away from the light emission center, the monitor light can be cut out without giving excessive loss to the communication light.

  On the other hand, of the light that is optically coupled to the optical fiber 5 from the communication light output region 14, the light that passes through the outer periphery of the communication light output region 14 has a large incident angle to the optical fiber 5 and is higher in order during propagation. Mode light can be excited. For this reason, a spot-like intensity distribution is generated by the inter-mode interference of the transmitted light, which can be a cause of deterioration in transmission quality due to mode speckle noise. However, as described above, if the monitor light emitting region 13 is provided on the peripheral portion S11 over the entire outer periphery of the light S10 incident from the incident region 11, it passes through the outer periphery of the communication light emitting region 14. Since the light can be removed from the communication light, the generation of mode speckle noise can be prevented. Therefore, deterioration of transmission quality can be suppressed.

  Next, a second modification of the first embodiment will be described with reference to FIG. The difference from the first modification of the first embodiment is that, in the branch region Z10b, the monitor light is not transmitted and branched, but is reflected in a direction different from the direction D3 in which the communication light propagates. At the point of branching. Further, the light emitting element 3 and the light monitor 4 are provided on the same side with respect to the optical member 1b, and the branch region Z10b reflects a part of the light incident on the branch region Z10b in the direction D4 (first direction). A reflection surface 12b coupled to the monitor light emission region 13b is further provided.

  The optical member 1b according to the second modification of the first embodiment includes an incident region 11b, a reflecting surface 12b, a monitor light emitting region 13b (first emitting region), and a communication light emitting region 14b (second emitting region). , A branch region Z10b, a light propagation region Z11b (first light propagation region), and a light propagation region Z12b (second light propagation region).

  The incident area 11b is an area for allowing the light emitted from the light emitting element 3 to enter the optical member 1b.

  The reflecting surface 12b is a surface that reflects light incident from the incident region 11b. The reflective surface 12b is different from the reflective surface 12 of the optical member 1 according to the first embodiment in the following points. That is, while the reflecting surface 12 of the optical member 1 is a single flat surface, the reflecting surface 12b is composed of a flat central reflecting surface 12b2 and a peripheral reflecting surface 12b1 provided around the central reflecting surface 12b2. Has been. The peripheral reflection surface 12b1 is provided with a protrusion around the central reflection surface 12b2, and one of the protrusions is a reflection surface. The peripheral reflection surface 12b1 is a surface having an angle different from that of the central reflection surface 12b2. Specifically, this angle is as follows. That is, the peripheral reflection surface 12b1 reflects the light incident through the peripheral portion S11b on the outer periphery of the light S10b toward the light propagation region Z11b. On the other hand, the central reflecting surface 12b2 has an angle that reflects the light incident through the central portion S12b of the light S10b toward the light propagation region Z12b.

  The branch region Z10b is a region including the reflecting surface 12b in the optical member 1b. A light propagation region Z11b (extending in the direction D4 optically coupled to the light monitor 4) and a light propagation region Z12b (extending in the direction D3) are connected to the branch region Z10b. The light propagation region Z11b is a region connected to the branch region Z10b. A monitor light emission region 13b is connected to the end of the light propagation region Z11b. The light propagation region Z12b is a region connected to the branch region Z10b. A communication light emitting region 14b is connected to the end of the light propagation region Z12b. In the second modification of the first embodiment, the light emitting element 3 and the light monitor 4 are formed on the same substrate.

  Then, the function of the optical member 1b which concerns on the 2nd modification of 1st Embodiment is demonstrated. The light emitted from the light emitting element 3 enters the optical member 1b through the incident region 11b. The light incident on the optical member 1b travels in the direction D1 and is reflected by the reflecting surface 12b. Of the light incident on the optical member 1b, the light incident through the peripheral portion S11b on the outer periphery of the light S10b is reflected by the peripheral reflection surface 12b1, propagates in the light propagation region Z11b in the direction D4, and is monitored light emission region Optically coupled to the optical monitor 4 via 13b. On the other hand, of the light incident on the optical member 1b, the light incident through the central portion S12b of the light S10b is reflected by the central reflecting surface 12b2, propagates in the light propagation region Z12b in the direction D3, and transmits the communication light emitting region 14b. Is optically coupled to the optical fiber 5 via

  Also in the optical member 1b according to the second modification of the first embodiment described above, the same operations and effects as those of the optical member 1 according to the first embodiment are obtained. That is, the optical member 1b branches the light incident through the peripheral portion S11b of the light S10b emitted from the light emitting element 3 in a direction optically coupled to the light monitor 4 by reflecting the light by the peripheral reflecting surface 12b1. The optical path is optically coupled to the monitor light emitting area 13b without changing the direction of the optical path, and is incident on the optical monitor 4 through the monitor light emitting area 13b. Therefore, the optical power can be monitored with high accuracy.

  Moreover, the light emitting element 3 and the light monitor 4 are attached to the optical member 1b by further including a reflection surface 12b that reflects a part of the light incident on the branch region Z10b in the first direction and couples it to the monitor light emitting region 13b. On the other hand, it can be provided on the same side (when the monitor light is transmitted and branched, it is the opposite side). Therefore, the light emitting element 3 and the light receiving element 4 can be formed on the same substrate 6. Therefore, the entire module can be reduced in size.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view of the optical member 2 according to the second embodiment. The optical member 2 includes an incident region 21, a deflection surface 22A (deflection unit), a branch surface 22B (reflection surface), a monitor light emission region 23 (first emission region), and a communication light emission region 24 (second emission region). A branch region Z20, a light propagation region Z21 (first light propagation region), and a light propagation region Z22 (second light propagation region).

  The incident area 21 is an area where light emitted from the light emitting element 3 is incident on the optical member 2. Further, the deflection surface 22A causes light incident in the direction D1 from the light emitting element 3 via the incident region 21 to a direction of the branch region Z20 that is different from the light emission direction of the incident region 21 (toward the direction D3). To deflect.

  The branch surface 22B is provided on the path of light deflected by the deflection surface 22A (the path extending in the direction D3). More specifically, the branch surface 22B is provided in the peripheral portion S21 on the outer periphery of the light S20 that enters the branch region Z20 via the deflection surface 22A. The branch surface 22B reflects light passing through the peripheral portion S21 of the light S20 deflected by the deflecting surface 22A to branch in the direction D5, and passes through the light propagation region Z21 extending in the direction D5 to pass through the monitor light emitting region 23. Optically coupled to The direction D5 in which the light propagation region Z21 extends is different from the incident direction (direction D3) of the light incident on the branch region Z20, and is the incident direction (direction D1) of the light in the incident region 21. The optical member 2 faces the same side.

  The communication light emitting region 24 emits light (light traveling in the direction D3) that has passed through the central portion S22 of the light S20 deflected by the deflecting surface 22A and optically couples it to the optical fiber 5.

  The branch region Z20 is a region having the branch surface 22B in the optical member 2. The light propagation region Z21 and the light propagation region Z22 are connected to the branch region Z20. The light propagation region Z21 is a region connected to the branch region Z20. A monitor light emitting region 23 is connected to the end of the light propagation region Z21. The light propagation region Z22 is a region connected to the branch region Z20. Further, a communication light emitting region 24 is connected to the end of the light propagation region Z22.

  The monitor light emission region 23 optically couples the light reflected by the branch surface 22B and passing through the light propagation region Z21 to the optical monitor 4. The communication light emission region 24 optically couples the light reflected by the deflecting surface 22 </ b> A and passing through the light propagation region Z <b> 22 to the optical fiber 5.

  Next, the function of the optical member 2 will be described. Light emitted from the light emitting element 3 enters the optical member 2 from the incident region 21. The light incident on the optical member 2 travels in the direction D1, and is deflected in the direction D3 different from the direction D1 by the deflection surface 22A. The light passing through the peripheral portion S21 on the outer periphery of the light S20 traveling in the direction D3 is incident on the branch region Z20, then is branched at the branch surface 22B, passes through the light propagation region Z21 extending in the direction D5, and is then monitored light emission region The optical monitor 4 is optically coupled to the optical monitor 4. On the other hand, the light passing through the central portion S22 of the light S20 deflected by the deflecting surface 22A enters the branch region Z20, then passes through the light propagation region Z22 extending in the direction D3, and passes through the communication light emitting region 24 to the optical fiber. 5 is optically coupled.

  As described above, the optical member 2 branches the light emitted from the light emitting element 3 and deflected by the deflecting surface 22A by the branch surface 22B, and then optically enters the monitor light emitting region 23 without changing the direction of the optical path. Then, the light is incident on the light receiving element 4 through the monitor light emitting region 23. Therefore, the branched optical path in the optical member 2 optically coupled to the optical monitor 4 is shortened, and the optical power can be monitored with high accuracy. Further, the light emission direction D1 from the incident region 21 and the direction D5 which is the direction of the light after being reflected by the branch surface 22B are directed to the same side with the optical member 2 interposed therebetween. Therefore, the light emitting element 3 and the light receiving element 4 can be formed on the same substrate 6. Therefore, the entire module can be reduced in size.

  In FIG. 5, the branch surface 22B is provided, for example, in the peripheral portion S21 of the light S20 deflected from the deflection surface 22A. The peripheral portion S21 does not extend over the entire outer periphery of the light S20. However, as shown in FIG. 6, the peripheral portion S21 may extend over the entire outer periphery of the light S20.

  FIG. 6 is a diagram for explaining a configuration of a modified example of the second embodiment. The optical member 2a according to the modification of the second embodiment includes an incident region 21a, a deflection surface 22Aa (deflection unit), a branch surface 22Ba (reflection surface), a monitor light emission region 23a (first emission region), and communication light emission. A region 24a (second emission region), a branch region Z20a, a light propagation region Z21a (first light propagation region), and a light propagation region Z22a (second light propagation region) are provided. Among these, the incident region 21a and the deflection surface 22Aa have the same configuration and action as the incident region 21 and the deflection surface 22A in the optical member 2.

  The optical member 2a is different from the optical member 2 in that the peripheral portion S21a on the outer periphery of the light S20a has a ring shape over the entire outer periphery of the light S20a. Since the branch surface 22Ba is provided in the peripheral portion S21a of the light S20, the shape of the branch surface 22Ba is also a ring shape. Accordingly, the light propagation region Z21a, which is a region through which the light reflected by the branch surface 22Ba propagates, also has a cylindrical shape extending in the direction D5. On the other hand, the light propagation region Z22a has a columnar shape protruding in the direction D3 from the branch surface 22Ba. And the communication light emission area | region 24a is provided in the edge part of the light propagation area | region Z22a. Since the light propagation region Z22a has a columnar shape, legs can be provided around the light propagation region Z22a and mounted on the substrate.

  With such an optical member 2a, the branch region reflects a part of incident light in the direction D5 (first direction) and couples it to the monitor light emitting region 23a. The emission direction D1 and the direction D5 that is the direction of light after being reflected by the second reflecting surface 22B are directed to the same side with the optical member 2 interposed therebetween. Therefore, the light emitting element 3 and the light receiving element 4 can be formed on the same substrate 6. Further, since the peripheral portion S21a on the outer periphery of the light S20a has a ring shape over the entire outer periphery of the light S20a, light passing through the outer periphery of the communication light emitting region 24a can be removed from the communication light. That is, it is possible to suitably prevent the higher-order mode light from being excited in the communication light, and to prevent the occurrence of mode speckle noise. Therefore, deterioration of transmission quality can be suppressed.

  DESCRIPTION OF SYMBOLS 1,2 ... Optical member 11,21 ... Incident area | region, 12 ... Reflection surface, 22A ... Deflection surface, 22B ... Branch surface, 13, 23 ... Communication light emission area | region, 14, 24 ... Monitor light emission area | region, Z10, Z20 ... Branch region, Z11, Z12, Z21, Z22 ... Light propagation region.

Claims (5)

An incident region where light emitted from the light emitting element is incident;
A branch region that branches light incident from the incident region in a first direction and a second direction;
A first emission region for emitting the light branched in the first direction to the outside;
A second emission region for emitting the light branched in the second direction to the outside;
With
The first exit region is optically coupled to an external light monitor;
The second exit region is optically coupled to an external optical waveguide;
The light branched in the first direction reaches the first emission region without changing the optical path;
An optical member. The incident area, the first emission area, and the second emission area all include a collimator lens,
The branch region branches at least a part of the outer periphery of the light collimated by the incident region in the first direction;
The optical member according to claim 1. The branch region branches the entire outer periphery of the light collimated by the incident region in the first direction.
The optical member according to claim 2. The light emitting element and the optical monitor are provided on the same side with respect to the optical member,
The branch region has a reflective surface that reflects a part of light incident on the branch region in the first direction and couples the light to the first output region.
The optical member according to claim 1, wherein the optical member is an optical member. A deflection unit that deflects light incident from the incident region to the branch region is further provided between the incident region and the branch region.
The optical member according to claim 4.

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