Optical module

Abstract

To provide an optical module which can be miniaturized.SOLUTION: An optical module according to the present disclosure includes a light output unit that outputs light, a lens including an incidence surface on which the light output from the light output unit is incident and an emission surface having a first emission portion that emits the light incident on the incidence surface, and a light receiving element that receives the light refracted by the incidence surface.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to optical modules. [Background technology]

[0002] In an optical transceiver, an optical module called a Transmitter Optical Subassembly (TOSA) is used to transmit an optical signal. As a related technique for optical modules such as TOSA, there is an optical module disclosed in Patent Document 1.

[0003] According to the optical module disclosed in Patent Document 1, light output from a light-emitting element passes through a first lens corresponding to a collimating lens and is reflected by a reflecting surface located after the first lens. The light reflected by the reflecting surface is then collected and received by a light-receiving element corresponding to a monitor PD (Photo Diode), thereby monitoring the optical power with the light-receiving element. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-004916 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in recent years, to cope with the further spread of optical communications and to ensure competitiveness against rival companies, there has been a demand for miniaturization of optical modules such as TOSA.

[0006] However, the optical module disclosed in Patent Document 1 is configured to utilize light reflected by a reflective surface, which requires the provision of a reflective surface. Furthermore, since the path of the light output from the light-emitting element and the path of the light reflected by the reflective surface must be different, the path of the light becomes longer. This makes it difficult to miniaturize the optical module.

[0007] In view of the above-mentioned problems, an object of the present disclosure is to provide an optical module that can be made smaller. [Means for solving the problem]

[0008] An optical module according to one aspect includes: an optical output unit that outputs light; a lens including an incident surface on which the light output from the light output portion is incident and an exit surface having a first exit portion that emits the light incident on the incident surface; and a light receiving element that receives the light refracted by the incident surface. [Effects of the Invention]

[0009] According to the above-described aspect, it is possible to provide an optical module that can be made smaller. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of an optical module according to a related art. [Figure 2] 1A and 1B are diagrams illustrating an example of the configuration of a light-emitting element according to the present disclosure. [Figure 3] 3 is a diagram showing a specific example of the configuration of the light-emitting element shown in FIG. 2. FIG. [Figure 4] 1A and 1B are diagrams illustrating an example of the configuration of a light-emitting element according to the present disclosure. [Figure 5] 1 is a diagram illustrating an example of the configuration of an optical module according to the present disclosure. [Figure 6] 1A and 1B are diagrams illustrating an example of mounting an optical module according to a related art. [Figure 7] 1A and 1B are diagrams illustrating an example of an implementation of an optical module according to the present disclosure. [Figure 8] 1 is a diagram illustrating an example of the configuration of an optical module according to the present disclosure. [Figure 9] 1 is a diagram illustrating an example of the configuration of an optical module according to the present disclosure. [Figure 10] 1 is a diagram illustrating an example of the configuration of an optical module according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following description and drawings have been omitted and simplified as appropriate for clarity of explanation. In addition, in the following drawings, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary. In addition, in the following description, the optical module will be described as a TOSA, but examples of optical modules are not limited to TOSAs.

[0012] <Related technologies> Before describing each embodiment of the present disclosure, a related art will be described. 1 is a diagram showing an example of the configuration of an optical module 90 according to related art. Note that the optical module 90 is an optical module that the present inventors have studied, and is not the optical module disclosed in Patent Document 1.

[0013] 1, an optical module 90 includes a light emitting element 91, a collimator lens 92, an isolator 94, a prism 97, a monitor PD 93, a condenser lens 95, and an optical fiber 96. In FIG. 1, the optical path is indicated by a dotted line (the same applies to the following drawings).

[0014] The light emitting element 91 is an element that outputs light. The collimating lens 92 is a lens that collimates the light output from the light emitting element 91 . The isolator 94 is an element that reduces the amount of light that returns to the collimator lens 92 out of the light that has been output from the collimator lens 92 and passed through the isolator 94 .

[0015] The prism 97 is an element that branches the light output from the isolator 94 and outputs the branched light to the monitor PD 93 and the condenser lens 95. As shown in Fig. 1, the prism 97 may have a half mirror that transmits and reflects a certain proportion of the incident light. In this case, the prism 97 outputs the transmitted light and the reflected light to the monitor PD 93 and the condenser lens 95, respectively. The monitor PD 93 is an element that receives the light branched by the prism 97 and monitors the optical power of the received light. For example, based on the optical power monitored by the monitor PD 93, a control unit (not shown) adjusts the optical power of the light output from the light-emitting element 91.

[0016] The condenser lens 95 is a lens that condenses the light output from the prism 97 into the optical fiber 96 . The optical fiber 96 is an optical fiber that propagates the light output from the condenser lens 95 .

[0017] As described above, there is a demand for miniaturization of the optical module 90. In each of the embodiments described below, the prism 97 constituting the optical module 90 is eliminated to achieve miniaturization of the optical module.

[0018] <Prerequisite configuration for each embodiment> Next, the prerequisite configurations of the first and second embodiments will be described.

[0019] In the first and second embodiments, it is assumed that a light emitting element having the following functions is used. The light is output at an angle to the collimating lens in the subsequent stage. For example, the light emitting element emits light at an angle that is not parallel to the optical axis of the collimating lens. The light has an emission angle (for example, the angle between the optical axis of the collimator lens and the direction of travel of the light output from the light emitting element) and a spread angle. The emission angle and spread angle of the light may be large.

[0020] Furthermore, in the first and second embodiments, it is assumed that a collimator lens having the following functions is used. The lens diameter is such that some of the light emitted from the light-emitting element at an angle is refracted, causing light leakage.

[0021] Here, an example of the light emitting elements used in the first and second embodiments will be described. Here, two light emitting elements 11X and 11Y will be taken as an example.

[0022] FIG. 2 is a diagram showing an example of the configuration of a light emitting device 11X according to the present disclosure. 2, the light-emitting element 11 has an inclined optical axis 111 and is configured to output light in the direction of the inclined optical axis 111. Therefore, the light-emitting element 11X outputs light that is inclined with respect to the collimating lens at the subsequent stage. Furthermore, the light emitting element 11X is configured so that the emission angle 112 and the spread angle 113 of the light are large.

[0023] FIG. 3 is a diagram showing a specific example of the configuration of the light emitting element 11X shown in FIG. As shown in FIG. 3, for example, the light emitting element 11X can be configured to include an SOA (Semiconductor Optical Amplifier) ​​114, a SiPh (Silicon Photonics) chip 115, and a BOA (Booster Optical Amplifier) ​​.

[0024] The SOA 114 is a light source that outputs light. The SiPh chip 115 is a chip that performs various processes on the light output from the SOA 114, including wavelength adjustment and modulation. The BOA 116 is an amplifier that amplifies the light output from the SiPh chip 115 and outputs the amplified light.

[0025] FIG. 4 is a diagram showing a configuration example of a light emitting device 11Y according to the present disclosure. 4, the light emitting element 11Y is installed so that the light emitting element 11Y itself is tilted, and therefore the light emitting element 11Y outputs light that is tilted with respect to the collimating lens at the subsequent stage. Similarly to the light emitting element 11X, the light emitting element 11Y has a large light emission angle 112 and a large spread angle 113.

[0026] In the first and second embodiments described below, either the light emitting element 11X or 11Y can be used, but it is preferable to use the light emitting element 11X in consideration of the mounting area, etc. Therefore, in the first and second embodiments, the light emitting element 11X will be used. Hereinafter, each embodiment including the first and second embodiments will be described.

[0027] <First Embodiment> FIG. 5 is a diagram showing an example of the configuration of an optical module 10 according to the present disclosure. As shown in FIG. 5, the optical module 10 includes a light emitting element 11, a collimating lens 12, a monitor PD 13, an isolator 14, a condenser lens 15, and an optical fiber 16.

[0028] The light emitting element 11 is an element that outputs light, and is realized by a light emitting element 11X. Therefore, the light emitting element 11 has an inclined optical axis 111, and outputs light at an angle relative to the downstream collimator lens 12. Furthermore, the light emitting element 11 has a large emission angle 112 and a large spread angle 113 of light.

[0029] Collimating lens 12 is a lens that collimates the light output from light-emitting element 11, and includes an incident surface 121 onto which the light output from light-emitting element 11 is incident, and an exit surface 122 having a first exit portion 123 that emits collimated light from the light incident on incident surface 121. As shown in Fig. 5 , the direction in which first exit portion 123 emits light is different from the direction of optical axis 111 of light-emitting element 11.

[0030] Here, the lens diameter of the collimator lens 12 is set so that a part of the light outputted from the light emitting element 11 at an angle is refracted at the incident surface 121, thereby causing leakage light L to occur.

[0031] In optical module 10, light refracted by incident surface 121 is emitted from second exit portion 124, which is located at a position on exit surface 122 different from first exit portion 123, and becomes leaked light L. The optical power of leaked light L is approximately 0.2 to 0.5 [dB].

[0032] Therefore, in optical module 10, monitor PD 13 is installed near collimating lens 12, and generally on the negative X and Y sides as viewed from collimating lens 12, and monitor PD 13 receives leakage light L and monitors the optical power of leakage light L. Then, for example, a control unit (not shown) adjusts the optical power of light output from light-emitting element 11 based on the optical power monitored by monitor PD 13. This makes it possible to eliminate prism 97, which constitutes optical module 90, from optical module 10.

[0033] 5 is an example. For example, there is a case where leakage light L is output from the collimator lens 12 to the negative side in the X direction and the positive side in the Y direction. In such a case, the monitor PD 13 may be disposed roughly on the negative side in the X direction and the positive side in the Y direction as viewed from the collimator lens 12.

[0034] The isolator 14 is an element that reduces the return light that returns to the collimator lens 12 out of the light that is output from the first emission part 123 of the collimator lens 12 and passes through the isolator 14 . The condenser lens 15 is a lens that condenses the light output from the isolator 14 into the optical fiber 16 . The optical fiber 16 is an optical fiber that propagates the light output from the condenser lens 15 .

[0035] Thus, the functions of the isolator 14 , the condenser lens 15 , and the optical fiber 16 in the optical module 10 are substantially the same as the functions of the isolator 94 , the condenser lens 95 , and the optical fiber 96 in the optical module 90 .

[0036] As described above, according to this embodiment 1, the optical module 10 is configured so that the leaked light L that is refracted by the incident surface 121 of the collimator lens 12 and emitted from the second emission portion 124 of the collimator lens 12 is received by the monitor PD 13.

[0037] This makes it possible to eliminate the prism 97 included in the optical module 90 according to the related art. As a result, the optical module 10 can be made smaller than the optical module 90 according to the related art. Furthermore, because the prism 97 is eliminated, the component costs and mounting costs for the prism 97 can be reduced. As a result, the optical module 10 can be made less expensive than the optical module 90 according to the related art. Furthermore, in the optical module 10, the optical power of the light extracted for monitoring by the monitor PD 13 is approximately 0.2 to 0.5 dB, which is the same as when the prism 97 is used. Therefore, the optical module 10 can be made smaller and less expensive than the optical module 90 according to the related art, without increasing the optical loss of the entire optical module.

[0038] Furthermore, since the optical module 10 can eliminate the prism 97, it is free from the effects of mounting errors resulting from the mounting of the prism 97. Furthermore, it is free from the effects of positional and angular deviations of the prism 97 that may occur when there is a temperature change. As a result, the optical module 10 is able to suppress fluctuations in the optical output to the optical fiber 16, compared to the optical module 90 according to the related art.

[0039] Furthermore, compared to the optical module 90 according to the related art, the optical module 10 is capable of controlling the temperatures of all of the basic components that make up the optical module 10, which also makes it possible to improve reliability. This effect will be explained below.

[0040] Fig. 6 is a diagram illustrating an example of implementation of an optical module 90 according to the related art. In the example of Fig. 6, the light-emitting element 91 constituting the optical module 90 is realized by the light-emitting element 11X shown in Fig. 3. In addition, in the example of Fig. 6, the optical fiber 96 is omitted.

[0041] As shown in FIG. 6, the optical module 90 is provided with a TEC (Thermoelectric cooler) 17, and the temperature of components arranged on the TEC 17 can be controlled. The TEC 17 has a stepped structure in the Z direction, including an upper stage 17a and a lower stage 17b. The size (X and Y dimensions) of a general-purpose TEC 17 is predetermined, and a custom-made product can be made larger, but this increases the cost. Therefore, considering the cost, it is preferable to use a general-purpose TEC 17.

[0042] However, it is difficult to reduce the size of the optical module 90 because it is configured with the prism 97. Therefore, among the components that make up the optical module 90, the monitor PD 93, the condenser lens 95, and the prism 97 cannot be disposed on the TEC 17.

[0043] As a result, the optical module 90 contains a mixture of components arranged on the TEC 17 and components not arranged on the TEC 17. In this case, when there is a temperature change, the amount of positional deviation differs between the components arranged on the TEC 17 and the components not arranged on the TEC 17, resulting in a large fluctuation in the optical output to the optical fiber 96.

[0044] Fig. 7 is a diagram illustrating an example of mounting an optical module 10 according to the present disclosure. Note that, in the example of Fig. 7, the light-emitting element 11 constituting the optical module 10 is also realized by the light-emitting element 11X shown in Fig. 3. In the example of Fig. 7, the optical fiber 16 is omitted.

[0045] As shown in Fig. 7, the optical module 10 has a configuration in which the prism 97 is eliminated, thereby enabling miniaturization. Therefore, all of the basic components constituting the optical module 10 can be arranged on the TEC 17. Specifically, in the example of Fig. 7, the light emitting element 11, collimator lens 12, isolator 14, and condenser lens 15 are arranged on the upper stage 17a of the TEC 17, and the monitor PD 13 is arranged on the lower stage 17b of the TEC 17. The TEC 17 corresponds to a temperature control element.

[0046] As a result, the optical module 10 can control the temperatures of all of the basic components that make up the optical module 10, and therefore can suppress fluctuations in the optical output to the optical fiber 16 even when there is a temperature change, thereby improving the reliability of the optical module 10.

[0047] The above describes the advantageous effects of the optical module 10 compared to the optical module 90 according to the related art. However, the optical module 10 also provides advantageous effects compared to the optical module disclosed in Patent Document 1.

[0048] Specifically, since the optical module 10 can install the monitor PD 13 near the collimating lens 12, the optical path is simpler than in the optical module disclosed in Patent Document 1, and there is no need to provide a reflective surface. As a result, the optical module 10 can be made more compact than the optical module disclosed in Patent Document 1. Furthermore, since the optical path is simpler than in the optical module disclosed in Patent Document 1, the optical module 10 is easier to design and does not require the preparation of components with complex structures. As a result, the optical module 10 can also be made less expensive than the optical module disclosed in Patent Document 1.

[0049] <Embodiment 2> FIG. 8 is a diagram showing an example of the configuration of an optical module 10A according to the present disclosure. As shown in FIG. 8, the optical module 10A differs from the optical module 10 in the installation position of the monitor PD 13.

[0050] In the optical module 10, the leaked light L was emitted from the second emission portion 124 on the emission surface 122. Therefore, the monitor PD 13 was configured to receive the leaked light L by being installed near the collimator lens 12 and generally on the negative side in the X direction and the negative side in the Y direction when viewed from the collimator lens 12.

[0051] In contrast, in the optical module 10A, the leaked light L is emitted from a second emission part 124 located on a side surface 125 that shares at least one side with the incident surface 121 and the emission surface 122. Therefore, the monitor PD 13 is installed near the collimating lens 12 and generally on the negative side in the Y direction when viewed from the collimating lens 12, and is configured to receive the leaked light L.

[0052] 8 is an example. For example, there is a case where the leaked light L is output from the collimating lens 12 to the positive side in the Y direction, that is, from a second exit portion 124 (not shown) located on the side surface 126 opposite to the side surface 125. In such a case, the monitor PD 13 may be disposed roughly on the positive side in the Y direction when viewed from the collimating lens 12.

[0053] The optical module 10A differs from the optical module 10 only in the installation position of the monitor PD 13, and the other structures are the same as those of the optical module 10. Therefore, the optical module 10A can achieve the same effects as the optical module 10.

[0054] <Third Embodiment> The third embodiment corresponds to an embodiment that is a higher-level concept of the first embodiment described above. FIG. 9 is a diagram showing an example of the configuration of an optical module 20 according to the present disclosure. As shown in FIG. 9, the optical module 20 includes an optical output unit 21, a lens 22, and a light receiving element .

[0055] The light output unit 21 outputs light. The light output unit 21 corresponds to the light emitting element 11. The lens 22 includes an incident surface 221 on which the light output from the light output unit 21 is incident, and an exit surface 222 having a first exit unit 223 that emits the light that has entered the incident surface 221. The lens 22 corresponds to the collimating lens 12. The light receiving element 23 receives the light refracted by the incident surface 221. The light receiving element 23 corresponds to the monitor PD13.

[0056] 9 is an example. For example, there is a case where light refracted by the incident surface 221 is output from the lens 22 to the negative side in the X direction and the positive side in the Y direction. In such a case, the light receiving element 23 may be disposed roughly on the negative side in the X direction and the positive side in the Y direction when viewed from the lens 22.

[0057] As described above, according to the third embodiment, the optical module 20 is configured such that the light refracted by the incident surface 221 of the lens 22 is received by the light-receiving element 23. This allows the optical module 20 to be miniaturized. Specifically, the optical module 20 does not require a prism (such as the prism 97 constituting the optical module 90 according to the related art) for branching light to the light-receiving element 23, thereby enabling miniaturization. Furthermore, the optical module 20 eliminates the component and mounting costs of the prism, thereby enabling cost reduction. Furthermore, in the optical module 20, the optical power of the light received by the light-receiving element 23 is approximately 0.2 to 0.5 dB, which is equivalent to that when a prism is used. Therefore, the optical module 20 allows miniaturization and cost reduction without increasing the optical loss in the entire optical module, as compared to when a prism is used.

[0058] The light output unit 21 outputs light in the direction of the tilted optical axis, while the first output unit 223 outputs light in a direction different from the optical axis direction. In addition, in lens 22, the light refracted by incident surface 221 is output from second exit portion 224 provided at a position different from first exit portion 223.

[0059] In the optical module 20 , the second emission part 224 is located on the emission surface 222 . Therefore, the light receiving element 23 is installed near the lens 22 and, as viewed from the lens 22, roughly on the negative side in the X direction and the negative side in the Y direction, and receives light that is refracted by the incident surface 221 and emitted from the second emission section 224.

[0060] <Fourth Embodiment> The fourth embodiment corresponds to an embodiment that is a higher-level concept of the second embodiment described above. FIG. 10 is a diagram illustrating an example of the configuration of an optical module 20A according to the present disclosure. As shown in FIG. 10, the optical module 20A differs from the optical module 20 in the installation position of the light receiving element 23.

[0061] In the optical module 20A, the second emission part 224 is located on a side surface 225 that shares at least one side with the incident surface 221 and the emission surface 222. Therefore, the light receiving element 23 is installed near the lens 22 and roughly on the negative Y-direction side when viewed from the lens 22, and receives light that is refracted by the incident surface 221 and emitted from the second emission section 224.

[0062] 10 is an example. For example, there is a case where light refracted by incident surface 221 is output from lens 22 to the positive side in the Y direction, that is, output from second emission part 224 (not shown) located on side surface 226 opposite side surface 225. In such a case, light receiving element 23 may be disposed roughly on the positive side in the Y direction when viewed from lens 22.

[0063] Here, optical module 20A differs from optical module 20 only in the installation position of light receiving element 23, and other structures are the same as optical module 20. Therefore, optical module 20A can obtain the same effects as optical module 20.

[0064] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0065] Furthermore, the surface from which the monitoring light is emitted may be provided with an appropriate degree of roughness to scatter the light, thereby improving the positional tolerance of the monitor PD 13 and the light receiving element 23. Specifically, the spread angle of the light emitted from the second exit portions 124, 224 is increased. This improves the positional tolerance of the monitor PD 13 and the light receiving element 23. For example, the spread angle of the light emitted from the second exit portions 124, 224 is larger than the spread angle of the light emitted from the first exit portions 123, 223.

[0066] Furthermore, each drawing is merely an example for describing one or more embodiments. Each drawing may relate not only to one particular embodiment, but also to one or more other embodiments. As will be understood by those skilled in the art, various features described with reference to any one drawing can be combined with features shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features shown in any one drawing are necessarily required to describe an exemplary embodiment, and some features may be omitted.

[0067] Furthermore, some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes. (Appendix 1) an optical output unit that outputs light; a lens including an incident surface on which the light output from the light output portion is incident and an exit surface having a first exit portion that emits the light incident on the incident surface; a light receiving element that receives the light refracted by the incident surface, Optical module. (Appendix 2) the light output unit outputs light in an optical axis direction; the first exit portion emits the light incident on the incident surface in a direction different from the optical axis direction; 10. The optical module according to claim 1. (Appendix 3) the lens has a second exit portion provided at a position different from the first exit portion, the light receiving element receives the light refracted by the incident surface and emitted from the second emission portion. 3. The optical module according to claim 1 or 2. (Appendix 4) the second exit portion is located on the exit surface, 10. The optical module according to claim 3. (Appendix 5) the second exit portion is located on a side surface having at least one side shared with the incident surface and the exit surface; 10. The optical module according to claim 3. (Appendix 6) a spread angle of the light emitted from the second exit portion is larger than a spread angle of the light emitted from the first exit portion; 10. The optical module according to claim 3. (Appendix 7) an isolator through which the light emitted from the first emission portion of the lens passes; a condenser lens that condenses light that has passed through the isolator; an optical fiber that propagates the light focused by the focusing lens; a temperature control element capable of temperature control, the temperature control element includes the optical output unit, the lens, the light receiving element, the isolator, and the condenser lens. 3. The optical module according to claim 1 or 2. [Explanation of symbols]

[0068] 10,10A optical module 11, 11X, 11Y light-emitting element 111 Optical axis 112 Exit angle 113 Spread Angle 114 SOA 115 SiPh chips 116 BOA 12 Collimating lens 121 Incidence plane 122 Exit surface 123 First exit section 124 Second exit section 125,126 Side 13 Monitor PD 14 Isolator 15 Condenser lens 16 Optical Fiber 17 TEC 17a Upper 17b bottom row 20,20A Optical Module 21 Optical output section 22 Lens 221 Entrance plane 222 Exit surface 223 First exit part 224 Second exit section 225,226 Side 23 Photodetector L Light Leak

Claims

1. an optical output unit that outputs light; a lens including an incident surface on which the light output from the light output portion is incident and an exit surface having a first exit portion that emits the light incident on the incident surface; a light receiving element that receives the light refracted by the incident surface, Optical module.

2. the light output unit outputs light in an optical axis direction; the first exit portion exits the light incident on the incident surface in a direction different from the optical axis direction; 2. The optical module according to claim 1.

3. the lens has a second exit portion provided at a position different from the first exit portion, the light receiving element receives the light refracted by the incident surface and emitted from the second emission portion.

3. The optical module according to claim 1.

4. the second exit portion is located on the exit surface, 4. The optical module according to claim 3.

5. the second exit portion is located on a side surface having at least one side shared with the incident surface and the exit surface; 4. The optical module according to claim 3.

6. a spread angle of the light emitted from the second exit portion is larger than a spread angle of the light emitted from the first exit portion; 4. The optical module according to claim 3.

7. an isolator through which the light emitted from the first emission portion of the lens passes; a condenser lens that condenses light that has passed through the isolator; an optical fiber that propagates the light focused by the focusing lens; a temperature control element capable of temperature control, the temperature control element includes the optical output unit, the lens, the light receiving element, the isolator, and the condenser lens.

3. The optical module according to claim 1.

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