Optical module and optical receptacle

Abstract

To provide an optical module capable of inhibiting a tolerance range from being biased even if an end face of an optical transmission body is inclined.SOLUTION: The optical module comprises: a light receiving element; a light-emitting element; an optical transmission body; and an optical receptacle for causing reception light from an end face of the optical transmission body to reach the light receiving element and transmission light from the light-emitting element to reach the end face of the optical transmission body. In comparison to an optical module for comparison, in a direction along an optical path between a second optical surface and a transmission reflection part, a principal ray of the reception light is closer to a principal ray of the transmission light between the transmission reflection part and a first optical surface. The first optical surface deflects the reception light and the transmission light to get close to an extended line of a central axis of the optical transmission body.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an optical module and an optical receptacle. [Background technology]

[0002] There is known an optical receptacle for optically coupling light from an optical transmission body such as an optical fiber to a light receiving element arranged on a substrate and optically coupling light from a light emitting element arranged on a substrate to the optical transmission body. Such a method of communication using light to a light receiving element and light from a light emitting element via one optical transmission body is called bidirectional communication. Bidirectional communication via one optical transmission body does not require the use of an optical transmission body for transmission and an optical transmission body for reception, and can simplify the device. For example, Patent Document 1 discloses an optical transmission module having an optical member (optical receptacle) used for such bidirectional communication via one optical transmission body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-251375 A Summary of the Invention [Problem to be solved by the invention]

[0004] 1 shows a schematic cross-sectional view of a conventional optical module 1 used for the above-mentioned bidirectional communication. The optical module 1 has a light receiving element 20 and a light emitting element 30 arranged on a substrate 10, an optical receptacle 40, and an optical transmission body 50.

[0005] Bidirectional communication in such an optical module 1 is as follows. That is, received light from optical transmission body 50 to light receiving element 20 enters optical receptacle 40 from first optical surface 41 of optical receptacle 40, is reflected by transmission reflecting portion 40a, is emitted from optical receptacle 40 at second optical surface 42, and reaches light receiving element 20. On the other hand, transmitted light from light emitting element 30 to optical transmission body 50 enters optical receptacle 40 from third optical surface 43, is reflected by reflecting portion 44, is transmitted while being refracted at transmission reflecting portion 40a, is emitted from optical receptacle 40 at first optical surface 41, and reaches the end face of optical transmission body 50.

[0006] Here, it is preferable that the light from the light-emitting element 30 stably reaches the optical transmission body 50. Therefore, in order to allow the light from the light-emitting element 30 to stably reach the end face of the optical transmission body 50, the end face of the optical transmission body 50 may be inclined as shown in Fig. 1. By inclining the end face of the optical transmission body 50 in this manner, it is possible to suppress so-called return light, in which the transmitted light from the light-emitting element 30 emitted from the first optical surface 41 is reflected by the end face of the optical transmission body 50 and returns to the light-emitting element 30, and the operation of the light-emitting element 30 is stabilized.

[0007] However, the present inventors have found that tilting the end face of the optical transmission body 50 causes the following problem. That is, when the end face of the optical transmission body 50 is tilted, the light is refracted at the end face. Specifically, the transmitted light is refracted when it enters the end face of the optical transmission body 50, and the received light is refracted when it leaves the end face of the optical transmission body 50.

[0008] When the end face of optical transmission body 50 is inclined in this manner, light is refracted, and the inventors have found that this makes it difficult to align optical receptacle 40 with light receiving element 20 and light emitting element 30 arranged on substrate 10. This will be described below with reference to Figures 2A and 2B.

[0009] FIG. 2A is a graph showing the change in the coupling efficiency of received light and transmitted light relative to the misalignment of optical receptacle 40 when the end face of optical transmission body 50 is not inclined, and FIG. 2B is a graph showing the change in the coupling efficiency of received light and transmitted light relative to the misalignment of optical receptacle 40 when the end face of optical transmission body 50 is inclined.

[0010] 2A and B, the solid line shows the change in the coupling efficiency of received light when optical receptacle 40 is moved in the Z direction, based on the reference (movement amount 0 μm) when the center of second optical surface 42 is aligned with the center of light receiving element 20, and the dashed line shows the change in the coupling efficiency of transmitted light when optical receptacle 40 is moved in the Z direction, based on the reference (movement amount 0 μm) when the center of third optical surface 43 is aligned with the center of light emitting element 30. In Figures 2A and B, the coupling efficiency is represented as an upwardly convex curve, but the top of the curve has an approximately straight portion where the coupling efficiency does not change much even if the movement distance changes.

[0011] The substantially linear portion relates to the positional deviation tolerance range when aligning optical receptacle 40 with light receiving element 20 and light emitting element 30 arranged on substrate 10 .

[0012] Specifically, from the viewpoint of widening the positional deviation tolerance range, it is preferable that optical receptacle 40 is designed so that this straight-line portion is long. Also, from the viewpoint of suppressing a decrease in coupling efficiency even if the position is deviated in either of the two directions along the Z axis, it is preferable that optical receptacle 40 is designed so that the change in coupling efficiency is the same whether it is moved in the + direction or the - direction in the graph. That is, it is preferable that the midpoint of the approximately straight-line portion (hereinafter also referred to as the tolerance center) is located near the line of 0 μm of movement, and the curve showing the coupling efficiency is symmetrical with respect to the line of 0 μm of movement.

[0013] 2A and 2B, when the end face of the optical transmission body 50 is not inclined, the tolerance center is close to the line of zero movement (see FIG. 2A), but when the end face of the optical transmission body 50 is inclined, the tolerance center becomes farther from the line of zero movement (see FIG. 2B). For example, in the example shown in FIG. 2B, the light receiving element 20 or the light emitting element 30 relative to the optical receptacle 40 is vulnerable to misalignment in the + direction, and misalignment in this direction results in a large decrease in coupling efficiency. Note that FIGS. 2A and 2B are images for explaining changes in the tolerance range, and numerical values ​​are tentative.

[0014] An object of the present invention is to provide an optical module that can suppress deviation in the tolerance range even if the end face of the optical transmission body is inclined, and an optical receptacle used in the optical module. [Means for solving the problem]

[0015] The present invention relates to the following optical module and optical receptacle. [1] An optical module having a light receiving element, a light emitting element, an optical transmission body, and an optical receptacle for allowing received light from an end face of the optical transmission body to reach the light receiving element and for allowing transmitted light from the light emitting element to reach the end face of the optical transmission body, wherein the optical receptacle has a first optical surface for allowing the received light from the end face of the optical transmission body to enter an inside of the optical receptacle and for emitting the transmitted light that has passed through the inside of the optical receptacle toward the end face of the optical transmission body, and a second optical surface for making the transmission light from the light-emitting element incident on the light-receptacle enter the interior of the optical receptacle; a third optical surface that is disposed at a position farther from the first optical surface than the second optical surface, for making the transmission light from the light-emitting element incident on the light-receptacle enter the interior of the optical receptacle or for making the reception light that has passed through the interior of the optical receptacle exit toward the light-receiving element; and a third optical surface that reflects the reception light that has entered on the first optical surface toward the second optical surface and transmits the transmission light that has entered the interior of the optical receptacle on the third optical surface or for making the reception light that has passed through the interior of the optical receptacle exit toward the light-receiving element. a transmission reflector for reflecting the transmission light incident on the first optical surface toward the first optical surface and for transmitting the reception light incident on the first optical surface, and an end face of the optical transmission body facing the first optical surface is inclined with respect to a plane perpendicular to the central axis of the optical transmission body in a cross section including the central axis of the optical transmission body and parallel to the optical axis of the light emitting element, and the optical axis of the light emitted from the first optical surface and the central axis of the optical transmission body are aligned, compared to a comparative optical module configured such that and the first optical surface, a chief ray of the received light and a chief ray of the transmitted light are located closer to each other, an intersection point between the chief ray of the received light and the first optical surface is defined as a first intersection point, an intersection point between the chief ray of the transmitted light and the first optical surface is defined as a second intersection point, and when the chief ray of the received light, the chief ray of the transmitted light, the first intersection point, and the second intersection point are projected onto the cross section, the first intersection point and the second intersection point are located in the same region out of two regions bisected by an extension line of a central axis of the optical transmission body, and the first optical surface projects the chief ray of the received light and the chief ray of the transmitted light,An optical module that refracts the light so as to approach an extension line of the central axis of the optical transmission body. [2] The optical module described in [1], wherein the cross section includes an optical path between the first optical surface and the transmission-reflection section, and an optical path between the second optical surface and the transmission-reflection section. [3] The optical module described in [1] or [2], wherein, in the cross section, the center of the first optical surface is located at a position that does not overlap with an extension of the central axis of the optical transmission body, and the central axis of the first optical surface is inclined so as to approach the extension of the central axis of the optical transmission body as it approaches the transmissive reflector. [4] The optical module according to any one of [1] to [3], wherein a chief ray of the received light and a chief ray of the transmitted light overlap between the first optical surface and the transmitting / reflecting portion. [5] The optical module according to any one of [1] to [4], wherein a chief ray of the received light and a chief ray of the transmitted light are parallel to a bottom surface of the optical receptacle between the first optical surface and the transmitting / reflecting portion. [6] The optical module described in any one of [1] to [5], wherein a chief ray of the received light or the transmitted light between the second optical surface and the light receiving element or the light emitting element, and a chief ray of the transmitted light or the received light between the third optical surface and the light emitting element or the light receiving element are perpendicular to a bottom surface of the optical receptacle. [7] The optical module described in any one of [1] to [6], further comprising a reflecting section arranged on an optical path between the third optical surface and the transmissive reflecting section for reflecting the transmitted light from the third optical surface toward the transmissive reflecting section, or for reflecting the received light from the transmissive reflecting section toward the third optical surface. [8] An optical receptacle for use in the optical module described in any one of [1] to [7]. Effect of the Invention

[0016] According to the present invention, it is possible to provide an optical module that can suppress deviation in the tolerance range even when the end face of the optical transmission body is inclined, and an optical receptacle used in the optical module. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing a conventional (for comparison) optical module. [Diagram 2] 2A and 2B are graphs for explaining the deviation of the tolerance range of an optical receptacle. [Diagram 3] 3A to 3D are diagrams showing an optical module according to the first embodiment. [Figure 4] 4A and 4B are diagrams illustrating an optical module according to the first embodiment. [Diagram 5] 5A and 5B are diagrams showing optical paths in the optical module according to the first embodiment. [Figure 6] 6A and 6B are graphs showing the simulation results. [Figure 7] 7A and 7B are graphs showing the simulation results. [Figure 8] 8A to 8D are diagrams showing an optical module according to the second embodiment. [Figure 9] 9A and 9B are diagrams illustrating an optical module according to the second embodiment. [Figure 10] 10A to 10D are diagrams showing an optical receptacle according to the third embodiment. [Figure 11] 11A and 11B are diagrams illustrating an optical receptacle according to the third embodiment. [Figure 12] 12A to 12D are diagrams showing an optical module according to the fourth embodiment. [Figure 13] 13A and 13B are diagrams illustrating an optical module according to the fourth embodiment. [Figure 14] 14A to 14D are diagrams showing an optical module according to the fifth embodiment. [Figure 15] 15A and 15B are diagrams illustrating an optical module according to the fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] [Embodiment 1] [Optical module configuration] Hereinafter, an optical module according to a first embodiment of the present invention will be described in detail with reference to the drawings.

[0019] Fig. 3A is a plan view of the optical module 100 according to the first embodiment of the present invention, Fig. 3B is a bottom view, Fig. 3C is a front view, and Fig. 3D is a side view. Fig. 4A is a cross-sectional view taken along line AA in Fig. 3C, and Fig. 4B is a partially enlarged view of Fig. 4A. Figs. 5A and 5B are diagrams for explaining the optical path in the optical module 100 in a simplified manner, and are not drawn to actual scale.

[0020] 3A to 3D and 4A, the light receiving element, the light emitting element, and the light transmitting body are omitted, whereas in Fig. 4B, 5A, and 5B, the light receiving element 20, the light emitting element 30, and the light transmitting body 50 are shown, and the optical paths between them are also shown. As shown in FIGS. 3A to 5B, optical module 100 includes light receiving element 20 and light emitting element 30 arranged on substrate 10, optical transmission body 50, ferrule 60, and optical receptacle 400. As shown in FIG.

[0021] 5A and 5B show cases where the light receiving element 20 and the light emitting element 30 are arranged differently on the substrate 10. Fig. 5A shows a case where the light receiving element 20 is closer to the optical transmission body 50 than the light emitting element 30 is on the substrate 10. Fig. 5B shows a case where the light emitting element 30 is closer to the optical transmission body 50 than the light receiving element 20 is on the substrate 10. The optical paths for bidirectional communication in the embodiments of Figs. 5A and B are as follows, respectively.

[0022] That is, in Fig. 5A, in a cross section including the central axis CA1 of the optical transmission body and parallel to the optical axis of the light emitting element 30 (hereinafter, this cross section is also referred to as the "reference cross section"), the end face of the optical transmission body 50 facing the first optical surface 410 is inclined with respect to a plane perpendicular to the central axis of the optical transmission body 50. As a result, the received light from the end face of the optical transmission body 50 is refracted and emitted. In the example shown in Fig. 5A, the end face of the optical transmission body 50 is inclined so as to approach the optical receptacle 400 as it moves upward (away from the substrate 10). Therefore, the received light is refracted at the end face of the optical transmission body 50 so as to move upward (away from the substrate 10) and toward the upper side (opposite side of the substrate 10) of the extension line of the central axis of the optical transmission body 50 and is emitted. The received light thus emitted enters optical receptacle 400 while being refracted at first optical surface 410 of optical receptacle 400, is reflected at transmission / reflection section 450, is emitted from optical receptacle 400 at second optical surface 420, and reaches light receiving element 20. In addition, in Figures 5A and 5B, the reference cross section is a plane parallel to the YZ plane in the XYZ coordinate system consisting of mutually orthogonal X-axis, Y-axis, and Z-axis, when the axis parallel to central axis CA1 of optical transmission body 50 is set as the Z-axis. In addition, in this specification, the "optical axis of light-emitting element 30" means a central light ray of a three-dimensional emitted light flux from light-emitting element 30.

[0023] On the other hand, the transmission light emitted from light-emitting element 30 enters optical receptacle 400 from third optical surface 430 of optical receptacle 400, is reflected by reflecting section 440, passes through transmitting / reflecting section 450 while being refracted, and is emitted from optical receptacle 400 while being refracted by first optical surface 410 to reach the end face of optical transmission body 50. At this time, the transmission light is refracted at first optical surface 410 from a position above the extension of the central axis of optical transmission body 50 toward the extension of the central axis of optical transmission body 50 (below).

[0024] 5B, the end face of optical transmission body 50 is similarly inclined, and received light from the end face of optical transmission body 50 is refracted and emitted. As described above, received light is refracted at the end face of optical transmission body 50 so as to be emitted upward (to the opposite side of substrate 10) above the extension line of the central axis of optical transmission body 50. The received light thus emitted enters optical receptacle 400 while being refracted at first optical surface 410 of optical receptacle 400, transmits through transmission-reflection section 450 while being refracted, is reflected at reflection section 440, is emitted from optical receptacle 400 at third optical surface 430, and reaches light receiving element 20.

[0025] On the other hand, the transmission light emitted from light-emitting element 30 enters optical receptacle 400 from second optical surface 420, is reflected by transmission / reflection section 450, and is emitted from optical receptacle 400 while being refracted by first optical surface 410, and reaches the end face of optical transmission body 50. At this time, the transmission light is also refracted at first optical surface 410 from a position above the extension line of the central axis of optical transmission body 50 toward the extension line side (below) of the central axis of optical transmission body 50 and is emitted.

[0026] Here, in the optical module 100 shown in FIGS. 5A and 5B, the optical path is as follows compared to FIG. 1, which can prevent the tolerance range from being biased. That is, as can be seen from Figures 5A and 5B and Figure 1, compared to a comparative optical module (see Figure 1) in which the optical axis of the light emitted from the first optical surface 410 is configured to coincide with the central axis of the optical transmission body 50, in the direction along the optical path between the second optical surface 420 and the transmission reflector 450, the chief ray of the received light and the chief ray of the transmitted light are closer to each other between the transmission reflector 450 and the first optical surface 410 (hereinafter, this is also referred to as optical path condition 1).

[0027] Optical path condition 1 can also be expressed as follows: When the chief ray of the received light and the chief ray of the transmitted light between the transmitting and receiving section 450 and the first optical surface 410 are projected onto the above-mentioned reference cross section, the chief ray of the received light and the chief ray of the transmitted light in the optical module 100 of the present invention are closer to each other than the chief ray of the received light and the chief ray of the transmitted light in the comparative optical module 1.

[0028] 5A and 5B, when the intersection point between the principal ray of the received light and the first optical surface is defined as the first intersection point, the intersection point between the principal ray of the transmitted light and the first optical surface is defined as the second intersection point, and the principal ray of the received light, the principal ray of the transmitted light, the first intersection point P1, and the second intersection point P2 are projected onto the reference cross section, the first intersection point P1 and the second intersection point P2 are located in the same region of two regions bisected by an extension line of the central axis of the optical transmission body, and the first optical surface refracts the principal ray of the received light and the principal ray of the transmitted light so as to approach the extension line of the central axis of the optical transmission body (hereinafter, this is also referred to as optical path condition 2). In the present embodiment, the reference cross section includes the optical path between the first optical surface and the transmission-reflection section, and the optical path between the second optical surface and the transmission-reflection section. The case where the light is projected onto the reference plane includes the case where the chief ray of the received light and the chief ray of the transmitted light are on the reference plane. An example of a case where the chief ray of the received light and / or the chief ray of the transmitted light does not exist on the reference cross section is an optical module described in the third embodiment, which will be described later. By satisfying the optical path conditions 1 and 2, deviation of the tolerance range is suppressed. Details will be described later.

[0029] It is more preferable that the chief ray of the received light and the chief ray of the transmitted light be as follows. That is, as shown in Figures 5A and 5B, it is preferable that the chief ray of the received light and the chief ray of the transmitted light overlap between first optical surface 410 and transmission reflection unit 450. Also, as shown in Figures 5A and 5B, it is preferable that the chief ray of the received light and the chief ray of the transmitted light between first optical surface 410 and transmission reflection unit 450 are parallel to the bottom surface of optical receptacle 400. This further suppresses deviation of the tolerance range.

[0030] Hereinafter, each component of the optical module 100 according to the first embodiment will be described.

[0031] (substrate) There are no particular limitations on the substrate 10 as long as it is capable of arranging the light receiving element 20 and the light emitting element 30. Examples of the substrate 10 include a glass composite substrate, a glass epoxy substrate, a flexible substrate, and the like.

[0032] (Light receiving element and light emitting element) The light receiving element 20 is not particularly limited as long as it can receive light (received light). There may be one or more light receiving elements 20. In this embodiment, there are multiple light receiving elements 20 (for example, 12 elements), which are lined up in a row in the X direction. Examples of the light receiving elements 20 include photodiodes and the like. There is no particular limit to the light emitting element 30 as long as it can emit light (transmitted light). There may be one or more light emitting elements 30. In this embodiment, there are multiple light emitting elements 30 (for example, 12 elements), which are lined up in a row in the X direction. Examples of the light emitting elements 30 include VCSELs and the like.

[0033] It is not necessary for all the light receiving elements 20 to be arranged in a row, and it is not necessary for all the light emitting elements 30 to be arranged in a row. For example, in one optical module 100, four light receiving elements 20 and four light emitting elements 30 may be arranged to face four second optical surfaces 420 and four third optical surfaces 430, respectively, as shown in FIG. 5A, and the other four light receiving elements 20 and four light emitting elements 30 may be arranged to face four third optical surfaces 430 and four second optical surfaces 420, respectively, as shown in FIG. 5C. That is, the four light receiving elements 20 and four light emitting elements 30 may be arranged in a row in the X direction to face a plurality of second optical surfaces 420, and the other four light emitting elements 30 and four light receiving elements 20 may be arranged in a row in the X direction to face a plurality of third optical surfaces 430.

[0034] (Optical transmission body) The type of the optical transmission body 50 is not particularly limited. Examples of the type of the optical transmission body 50 include an optical fiber and an optical waveguide. The optical transmission body 50 may be one or more in number corresponding to the number of the light receiving element 20 and the light emitting element 30. In this embodiment, the number of the optical transmission bodies 50 is more than one (for example, 12) corresponding to the light receiving element 20 and the light emitting element 30, and they are arranged in a row in the X direction. As described above, in the above reference cross section, the end face of the optical transmission body 50 facing the first optical surface 410 is inclined with respect to a plane perpendicular to the central axis of the optical transmission body 50. In the example shown in FIGS. 5A and 5B, the end face of the optical transmission body 50 is inclined so as to approach the optical receptacle 400 as it goes upward (away from the substrate 10).

[0035] (Ferrule) Ferrule 60 is a member that holds an end of optical transmission body 50 and positions it with respect to optical receptacle 400. In the present embodiment, ferrule 60 is attached to optical receptacle 400 by a guide pin or the like, so that the end face of optical transmission body 50 is aligned with first optical surface 410.

[0036] (Optical receptacle) The configuration of optical receptacle 400 included in optical module 100 will now be described.

[0037] Optical receptacle 400 has a first optical surface 410, a second optical surface 420, a third optical surface 430, a reflecting portion 440, and a transflective portion 450.

[0038] Optical receptacle 400 is formed using a material that is transparent to light (transmitted light and received light) of a wavelength used in optical communication. Examples of such materials include transparent resins such as polyetherimide (PEI) and cyclic olefin resin. Optical receptacle 400 is manufactured by, for example, injection molding. Below, each component of optical receptacle 400 will be described.

[0039] <First optical surface> First optical surface 410 is a surface facing the end face of optical transmission body 50. First optical surface 410 allows received light from the end face of optical transmission body 50 to enter the inside of optical receptacle 400, and allows transmitted light that has passed through the inside of optical receptacle 400 to exit toward the end face of optical transmission body 50.

[0040] In the present embodiment, first optical surface 410 is configured to be able to control the incoming light and the outgoing light so as to satisfy the above-mentioned optical path conditions 1 and 2. This suppresses deviations in the tolerance range of optical receptacle 400.

[0041] In this embodiment, the first optical surface 410 is a convex lens surface, and its center C2 is located at a position that does not overlap with an extension of the central axis CA1 of the optical transmission body 50 in the reference cross section, as shown in Figures 5A and B. In the example shown in Figures 5A and B, the center C2 of the first optical surface 410 is located above the extension of the central axis CA1 of the optical transmission body 50 (on the opposite side to the substrate 10). In addition, the central axis CA2 of the first optical surface 410 is inclined so as to approach the extension of the central axis CA1 of the optical transmission body 50 as it approaches the transmission-reflection section 450.

[0042] <Second optical surface> Second optical surface 420 is disposed at a position closer to first optical surface 410 than third optical surface 430, and faces light receiving element 20 (see FIG. 5A) or light emitting element 30 (see FIG. 5B). In the present embodiment, second optical surface 420 is a convex lens surface that is convex toward light receiving element 20 or light emitting element 30, and causes received light that has passed through the inside of optical receptacle 400 to be emitted toward light receiving element 20 (see FIG. 5A), or causes transmitted light from light emitting element 30 to be incident into optical receptacle 400 (see FIG. 5B). In the present embodiment, received light that has passed through the inside of optical receptacle 400 is parallel light, and second optical surface 420 converges the parallel light to reach light receiving element 20 (see FIG. 5A). Alternatively, in the present embodiment, second optical surface 420 collimates light radially emitted from light emitting element 30 and causes the light to enter optical receptacle 400 (see FIG. 5B).

[0043] <Third optical surface> Third optical surface 430 is disposed at a position farther from first optical surface 410 than second optical surface 420, and faces light emitting element 30 (see FIG. 5A) or light receiving element 20 (see FIG. 5B). In the present embodiment, third optical surface 430 is a convex lens surface that is convex toward light emitting element 30 or light receiving element 20, and causes transmitted light from light emitting element 30 to enter optical receptacle 400 (see FIG. 5A), or causes received light that has passed through optical receptacle 400 to exit toward light receiving element 20 (see FIG. 5B). In the present embodiment, third optical surface 430 causes transmitted light radially emitted from light emitting element 30 to enter optical receptacle 400 so as to become parallel light (see FIG. 5A). Alternatively, in this embodiment, the received light that has passed through the inside of optical receptacle 400 is parallel light, and third optical surface 430 converges the parallel light to reach light receiving element 20 (see FIG. 5B).

[0044] <Transmission / reflection section> The transmission reflection unit 450 reflects the received light incident on the first optical surface 410 toward the second optical surface 420 and transmits the transmitted light incident inside the optical receptacle 400 at the third optical surface 430 (see FIG. 5A), or reflects the transmitted light incident inside the optical receptacle 400 at the second optical surface 420 toward the first optical surface 410 and transmits the received light incident on the first optical surface 410 (see FIG. 5B). The transmission reflection unit 450 only needs to have a function of reflecting one of the received light and the transmitted light having different wavelengths and transmitting the other. An example of such a transmission reflection unit 450 includes a wavelength separation filter. The wavelength separation filter is, for example, glass coated with a multilayer film.

[0045] 5A and 5B, in the present embodiment, transmission-reflection section 450 is disposed in rectangular parallelepiped recess 401b recessed from the top surface side of optical receptacle 400. Recess 401b serves to temporarily extract the received light and transmitted light to the outside of optical receptacle 400 and cause them to reach transmission-reflection section 450, thereby controlling the optical path.

[0046] The inner surface of the recess 401b has a transmitting surface. Specifically, the inner surface of the recess 401b has a first transmitting surface 410b located opposite the first optical surface 410, a second transmitting surface 420b located opposite the second optical surface 420, and a third transmitting surface 430b located opposite the reflecting portion 440.

[0047] 5A, received light that enters optical receptacle 400 at first optical surface 410 transmits through first transmitting surface 410b, enters recess 401b, and is reflected by transmitting and reflecting portion 450. The reflected received light transmits through second transmitting surface 420b, enters optical receptacle 400, and is emitted from optical receptacle 400 at second optical surface 420. On the other hand, the transmitted light that enters optical receptacle 400 at third optical surface 430 is reflected by reflecting portion 440, passes through third transmitting surface 430b and enters recess 401b, passes through transmitting reflecting portion 450 while being refracted, passes through first transmitting surface 410b and enters optical receptacle 400, and is emitted from optical receptacle 400 at first optical surface 410.

[0048] 5B, received light that enters optical receptacle 400 at first optical surface 410 passes through first transmitting surface 410b and enters recess 401b, passes through transmitting reflecting portion 450 while being refracted, and passes through third transmitting surface 430b to enter optical receptacle 400. The received light that enters optical receptacle 400 is reflected by reflecting portion 440, and is emitted from optical receptacle 400 at third optical surface 430. On the other hand, the transmission light that enters optical receptacle 400 at second optical surface 420 transmits through second transmitting surface 420b and enters recess 401b, is reflected by transmitting reflector 450, and transmits through first transmitting surface 410b to enter optical receptacle 400. The transmission light that has entered optical receptacle 400 is emitted from optical receptacle 400 at first optical surface 410.

[0049] Here, it is preferable that the transmissive reflector 450 is configured so as to realize the optical path conditions 1 and 2 as shown in Figures 5A and 5B described above. Specifically, for example, the transmissive reflector 450 is configured so that the thickness thereof is appropriately designed so that the optical paths of the received light and the transmitted light become the optical paths as shown in Figures 5A and 5B.

[0050] <Reflector> Reflecting section 440 is disposed on the optical path between third optical surface 430 and transmitting / reflecting section 450, and reflects the transmitted light from third optical surface 430 toward transmitting / reflecting section 450 (see FIG. 5A), or reflects the received light from transmitting / reflecting section 450 toward third optical surface 430 (see FIG. 5B). There are no particular limitations on reflecting section 440 as long as it can perform the above-mentioned functions. In the present embodiment, reflecting section 440 is a flat surface (inclined surface) inclined at an angle of 45° with respect to the bottom surface of optical receptacle 400.

[0051] (simulation) Fig. 6A is a graph showing a change in coupling efficiency of received light when the center of the light receiving element 20 is moved in the Z direction and the Y direction relative to the center of the second optical surface 420 in the optical module 100 according to the first embodiment as shown in Fig. 5A. In Fig. 6A, the solid line shows the case where the light receiving element 20 is moved in the Z direction, and the dashed line shows the case where the light receiving element 20 is moved in the Y direction. Similarly, Fig. 6B is a graph showing a change in coupling efficiency of received light when the center of the light receiving element 20 is moved in the Z direction and the Y direction relative to the center of the second optical surface 42 in the optical module 1 of the comparative example shown in Fig. 1. In Fig. 6B, the solid line shows the case where it is moved in the Z direction, and the dashed line shows the case where it is moved in the Y direction.

[0052] On the other hand, Fig. 7A is a graph showing a change in coupling efficiency of transmitted light when the center of the light-emitting element 30 is moved in the Z direction and the Y direction with respect to the center of the third optical surface 430 in the optical module 100 according to the first embodiment as shown in Fig. 5A. In Fig. 7A, the solid line shows the case where the light-emitting element 30 is moved in the Z direction, and the dashed line shows the case where the light-emitting element 30 is moved in the Y direction. Similarly, Fig. 7B is a graph showing a change in coupling efficiency of received light when the center of the light-emitting element 30 is moved in the Z direction and the Y direction relative to the center of the third optical surface 430 in the optical module 1 of the comparative example shown in Fig. 1. In Fig. 7B, the solid line shows the case where it is moved in the Z direction, and the dashed line shows the case where it is moved in the Y direction.

[0053] 6A and 6B, the point where the movement amount is 0 μm indicates the case where the center of the light receiving element 20 and the center of the second optical surface 420 coincide with each other when viewed from the Y direction. Similarly, in Figures 7A and 7B, the point where the movement amount is 0 μm indicates the case where the center of the light emitting element 30 and the center of the third optical surface coincide with each other when viewed from the Y direction.

[0054] As can be seen from a comparison between FIG. 6A and FIG. 6B and a comparison between FIG. 7A and FIG. 7B, in the optical module 100 according to the present embodiment, the line of 0 μm of movement and the center of the linear portion where the coupling efficiency does not change (tolerance center) are closer than in the optical module 1 of the comparative example. That is, in the optical module 100 according to the present embodiment, deviation of the tolerance range is suppressed. Specifically, in the example shown in FIG. 6A to FIG. 7B, deviation of the tolerance range (vulnerability to positional deviation in the + direction) in which the coupling efficiency suddenly decreases when each of the light receiving element 20 and the light emitting element 30 moves to a certain extent in the + direction is suppressed. This is because the optical module 100 satisfies the optical path conditions 1 and 2 as shown in FIG. 5A compared to FIG. 1.

[0055] (effect) According to the optical module 100 of the present embodiment, the optical path conditions 1 and 2 are satisfied, thereby suppressing deviations in the tolerance range.

[0056] [Other embodiments] Hereinafter, embodiments 2 to 5 will be described which satisfy optical path conditions 1 and 2 in the same manner as embodiment 1. The following description of embodiments 2 to 5 will focus on the differences from embodiment 1. In embodiments 2 to 5, the same components as in embodiment 1 will be denoted by the same reference numerals and the description thereof will be omitted.

[0057] [Embodiment 2] Fig. 8A is a plan view of the optical module 100a according to the second embodiment of the present invention, Fig. 8B is a bottom view, Fig. 8C is a front view, and Fig. 8D is a side view. Fig. 9A is a cross-sectional view taken along line AA in Fig. 8C, and Fig. 9B is a partially enlarged view of Fig. 9A.

[0058] In the optical module 100a, the inclination direction of the end face of the optical transmission body 50a is different from that of the optical module 100 according to the first embodiment. Accordingly, in the optical module 100a, the position and inclination direction of the first optical surface 410a are different from those of the first embodiment. Specifically, as shown in FIG. 9B, in the optical module 100a, the end face of the optical transmission body 50a is inclined so as to approach the optical receptacle 400a as it approaches downward (closer to the substrate 10). Therefore, the received light is refracted at the end face of the optical transmission body 50a so as to be directed downward (toward the substrate 10) from the extension line of the central axis CA1 of the optical transmission body 50a and is emitted (see FIG. 9B and FIG. 4B for comparison). In this embodiment, the center of the first optical surface 410a is located downward (toward the substrate 10) from the extension line of the central axis CA1 of the optical transmission body 50a. Moreover, the central axis of the first optical surface 410a is inclined so as to approach the extension line of the central axis CA1 of the optical transmission body 50a as it approaches the transmission-reflection portion 450. The optical receptacle 400a of the optical module 100a may be configured to satisfy the optical path conditions 1 and 2 for the received light refracted downward at the end face of the optical transmission body 50a. That is, as shown in FIG. 9B, in the optical module 100a, the optical path conditions 1 and 2 are satisfied in the lower region of the two regions divided in half by the extension line of the central axis CA1 of the optical transmission body 50 in the cross section including the optical path. In the first embodiment, the optical path conditions 1 and 2 are satisfied in the upper region of the two regions divided in half. As a result, in the second embodiment, the deviation of the tolerance range is suppressed similarly to the first embodiment (see comparison of FIG. 9B and FIG. 4B).

[0059] (effect) The optical module 100a according to the second embodiment has the same effects as the optical module 100 according to the first embodiment.

[0060] [Embodiment 3] Fig. 10A is a plan view of optical receptacle 400b according to embodiment 3 of the present invention, Fig. 10B is a bottom view, Fig. 10C is a front view, and Fig. 10D is a side view. Fig. 11A is a cross-sectional view taken along line AA in Fig. 10C, and Fig. 11B is a partially enlarged view of Fig. 11A.

[0061] Recess 401b of optical receptacle 400b differs from recess 401b of embodiment 1 in that it has a configuration for suppressing return light. Recess 401b will be described below.

[0062] As shown in FIG. 11B, recess 401b has first transmitting surface 411b, second transmitting surface 421b, and third transmitting surface 431b. In recess 401b, as shown in FIG. 10A, first transmitting surface 411b and second transmitting surface 421b are inclined with respect to a vertical plane perpendicular to central axis CA1 of optical transmission body 50. Specifically, in the present embodiment, when optical receptacle 400b is viewed in plan as shown in FIG. 10A, one end of first transmitting surface 411b is inclined so as to approach closer to the front surface of optical receptacle 400b, and the other end is inclined so as to move further away. Similarly, one end of second transmitting surface 421b is inclined so as to approach closer to the front surface of optical receptacle 400b, and the other end is inclined so as to move further away. Note that in the present embodiment, first transmitting surface 411b and second transmitting surface 421b are parallel to each other. In this way, by tilting the first transmitting surface 411b and the second transmitting surface 421b, the received light and the transmitted light do not transmit perpendicularly through the first transmitting surface 411b and the second transmitting surface 421b. Specifically, in the third embodiment, the received light and the transmitted light transmitted through the first transmitting surface 411b and / or the second transmitting surface 421b are refracted so as to move away from or approach the above-mentioned reference cross section (refracted in the X direction in FIGS. 5A and 5B). This suppresses so-called return light, in which the received light and the transmitted light are reflected by the first transmitting surface 411b and the second transmitting surface 421b and returned. The inclination angle may be appropriately set from the viewpoint of suppressing return light.

[0063] (effect) Optical receptacle 400b according to the third embodiment has the effect of suppressing deviations in the tolerance range, similar to embodiment 1. Furthermore, optical receptacle 400b according to the third embodiment has the effect of suppressing return light.

[0064] [Embodiment 4] Fig. 12A is a plan view of the optical module 100c according to the fourth embodiment of the present invention, Fig. 12B is a bottom view, Fig. 12C is a front view, and Fig. 12D is a side view. Fig. 13A is a cross-sectional view taken along line AA in Fig. 12C, and Fig. 13B is a partially enlarged view of Fig. 13A.

[0065] Optical module 100c according to the fourth embodiment has optical receptacle 400c. As shown in Fig. 13A, optical receptacle 400c differs from optical receptacle 400 according to the first embodiment in that optical receptacle 400c does not have a reflecting portion and has third optical surface 430 on the back surface of optical receptacle 400c.

[0066] 13B, in optical module 100c according to the fourth embodiment, when third optical surface 430 faces light receiving element 20, received light from optical transmission body 50 enters optical receptacle 400c from first optical surface 410, passes through transmission reflector 450, and is emitted from third optical surface 430 toward the light receiving element. On the other hand, when third optical surface 430 faces light emitting element 30, transmitted light from light emitting element 30 enters from third optical surface 430, passes through transmission reflector 450, and is emitted from first optical surface 410 toward the end face of optical transmission body 50.

[0067] (effect) The optical module 100c according to the fourth embodiment has the effect of suppressing deviations in the tolerance range, similar to the first embodiment.

[0068] [Embodiment 5] Fig. 14A is a plan view of optical receptacle 400d according to embodiment 5 of the present invention, Fig. 14B is a bottom view, Fig. 14C is a rear view, and Fig. 14D is a side view. Fig. 15A is a cross-sectional view taken along line AA in Fig. 14C. Fig. 15B is a partial enlarged view of Fig. 15A.

[0069] Optical receptacle 400d differs from optical receptacle 400 of the first embodiment in that it has groove 401d for holding optical transmission element 50 instead of ferrule 60. In the present embodiment, groove 401d is provided in plurality and extends in the direction from the front to the back of optical receptacle 400d. As shown in Fig. 15B, optical transmission element 50 placed in groove 401d is pressed down by lid 402d.

[0070] (effect) The optical module 100d according to the fifth embodiment has the effect of suppressing deviation in the tolerance range, similar to the embodiment 1. Moreover, in the optical module 100d according to the fifth embodiment, the optical transmission body 50 can be held by the groove 401d. [Industrial Applicability]

[0071] The optical module and optical receptacle according to the present invention are useful, for example, in optical communications using an optical transmission medium. [Explanation of symbols]

[0072] 1, 100, 100a, 100c, 100d Optical Module 10 Substrate 20 Photodetector 30 Light emitting element 40, 400, 400b, 400c, 400d Optical Receptacles 40a, 450 Transmissive reflective section 41, 410, 410a 1st optical surface 42, 420 Second optical surface 43, 430 Third optical surface 44, 440 Reflector 50, 50a Optical transmission body 60, 60a ferrule 401b Recess 401d Groove 402d lid 410b, 411b 1st transmission surface 420b, 421b 2nd transmission surface 430b, 431b 3rd transmission surface

Claims

1. A light receiving element; A light-emitting element; A light transmitting body; an optical receptacle for allowing received light from an end face of the optical transmission body to reach the light receiving element and for allowing transmitted light from the light emitting element to reach the end face of the optical transmission body; An optical module having The optical receptacle includes: a first optical surface for allowing the received light from the end face of the optical transmission body to enter an interior of the optical receptacle and for allowing the transmitted light that has passed through an interior of the optical receptacle to exit toward the end face of the optical transmission body; a second optical surface for emitting the received light that has passed through an interior of the optical receptacle toward the light receiving element or for causing the transmitted light from the light emitting element to enter an interior of the optical receptacle; a third optical surface that is disposed at a position farther from the first optical surface than the second optical surface, and that causes the transmission light from the light-emitting element to enter an interior of the optical receptacle or causes the received light that has passed through an interior of the optical receptacle to exit toward the light-receiving element; and a transmission / reflection section for reflecting the receiving light incident on the first optical surface toward the second optical surface and transmitting the transmitting light incident on the inside of the optical receptacle with the third optical surface, or for reflecting the transmitting light incident on the inside of the optical receptacle with the second optical surface toward the first optical surface and transmitting the receiving light incident on the first optical surface; having In a cross section including a central axis of the optical transmission body and parallel to an optical axis of the light emitting element, an end surface of the optical transmission body facing the first optical surface is inclined with respect to a plane perpendicular to the central axis of the optical transmission body, In comparison with a comparative optical module configured such that the optical axis of the light emitted from the first optical surface coincides with the central axis of the optical transmission body, a chief ray of the received light and a chief ray of the transmitted light are closer to each other between the transmission and reflection unit and the first optical surface in a direction along the optical path between the second optical surface and the transmission and reflection unit, an intersection point between a chief ray of the received light and the first optical surface is a first intersection point, an intersection point between a chief ray of the transmitted light and the first optical surface is a second intersection point, and when the chief ray of the received light, the chief ray of the transmitted light, the first intersection point, and the second intersection point are projected onto the cross section, the first intersection point and the second intersection point are located in the same region out of two regions divided in half by an extension line of a central axis of the optical transmission body, and the first optical surface refracts the chief ray of the received light and the chief ray of the transmitted light so as to approach the extension line of the central axis of the optical transmission body. Optical module.

2. The optical module according to claim 1 , wherein the cross section includes an optical path between the first optical surface and the transmission-reflection portion, and an optical path between the second optical surface and the transmission-reflection portion.

3. In the cross section, a center of the first optical surface is located at a position that does not overlap with an extension of a central axis of the optical transmission body, The central axis of the first optical surface is inclined so as to approach an extension line of the central axis of the optical transmission body as it approaches the transmission-reflection portion.

2. The optical module according to claim 1.

4. The optical module according to claim 1 , wherein a chief ray of the received light and a chief ray of the transmitted light overlap each other between the first optical surface and the transmitting / reflecting portion.

5. The optical module according to claim 1 , wherein a chief ray of the received light and a chief ray of the transmitted light are parallel to a bottom surface of the optical receptacle between the first optical surface and the transmission-reflection portion.

6. 2. The optical module according to claim 1, wherein a chief ray of the received light or the transmitted light between the second optical surface and the light receiving element or the light emitting element, and a chief ray of the transmitted light or the received light between the third optical surface and the light emitting element or the light receiving element are perpendicular to a bottom surface of the optical receptacle.

7. 2. The optical module according to claim 1, further comprising a reflecting section disposed on an optical path between the third optical surface and the transmission / reflection section, for reflecting the transmission light from the third optical surface toward the transmission / reflection section, or for reflecting the reception light from the transmission / reflection section toward the third optical surface.

8. An optical receptacle for use in the optical module according to any one of claims 1 to 7.

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