JP4163026B2 - Optical waveguide component and optical module using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical module used for, for example, optical communication and optical information processing, and more particularly to an optical transmission module having a configuration for monitoring a light output of a light emitting element such as a surface emitting laser diode. .
[0002]
[Prior art]
Conventionally, in a light emitting element such as a laser diode, the light emitted from the laser diode is monitored using a light receiving element such as a photodiode and fed back to a power source so that stable optical communication and optical information processing can be performed. The emitted light was controlled so as to emit light stably at a desired value.
[0003]
FIG. 5 is a diagram illustrating a configuration example of a conventional optical module. For example, since the edge-emitting laser 30 which is a typical laser diode has a structure having two light emitting surfaces as shown in FIG. 5A, the emitted light from one is used as a signal for the optical fiber 4. The incident light and the outgoing light from the other can be used by being incident on the light receiving element 3 for monitoring.
[0004]
As described above, since it is not necessary to split light specially for monitoring, the optical module configuration in the case of using the edge-emitting laser 30 is merely arranging the light receiving element 3, for example, a photodiode in the vicinity of the emission surface for monitoring. It's okay.
[0005]
However, since the light receiving structure of a general photodiode is a surface type, when an edge-emitting laser is mounted on a substrate, the photodiode needs to be arranged perpendicular to the substrate. On the other hand, when the photodiode is mounted on the substrate, the edge-emitting laser needs to be arranged perpendicular to the substrate.
[0006]
As described above, when an edge-emitting laser is used, a complicated mounting process is required, which becomes a problem particularly when an optical module in which a plurality of lasers are arrayed is manufactured.
[0007]
On the other hand, the surface emitting laser can be highly integrated, such as an array arrangement, and can be mounted on a substrate as compared with the conventional edge emitting laser 30, and can be mounted on a substrate. Recently, it has been attracting attention as a key component used for optical information processing that requires high integration.
[0008]
In the surface emitting laser, since one of the resonance mirrors is generally formed in the laser die, only the emitted light from the other mirror can be used. Therefore, when monitoring the emitted light, it is necessary to separate the light by some method and guide it to a photodiode as a light receiving element.
[0009]
As a method of separating light, a method of using a so-called half mirror that transmits a part of light and reflects the remaining part has been proposed (see Patent Document 1).
[0010]
That is, as shown in FIG. 5 (b), the half mirror 50 is installed at 45 ° above the surface emitting laser 40, and a part of the light is incident on the optical fiber 4 and the remaining part of the light receiving element 3 is incident.
[0011]
In this case, not only the half mirror 50 is required, but also the light receiving element 3 needs to be installed at right angles to the reflected light from the half mirror 50, which makes the assembly of the module complicated and makes it difficult to align the optical axis. .
[0012]
Further, as shown in FIG. 5C, a half mirror 50 is installed at 45 ° in front of the surface emitting laser 40 and another mirror 51 is installed, so that a part of the laser light is transferred to the substrate 100. A device that is incident on the light receiving element 3 mounted on is also proposed (see Patent Document 2). In this case, the light receiving element 3 can be installed on the same substrate as the surface emitting laser and can be mounted relatively easily. However, an optical component such as the lens 60 is required due to the use of two mirrors and a long optical path. As a result, the assembly becomes complicated and the optical axis alignment becomes more difficult.
[0013]
In addition, since these methods emit signal light perpendicular to the substrate, when signal light is incident on the optical fiber, it is necessary to arrange the optical fiber perpendicular to the substrate. It is difficult to realize a thin optical module.
[0014]
Further, as a method for facilitating the mounting, there is an example in which a surface emitting laser and a photodiode as a light receiving element are mounted on the same substrate, and light emitted from the surface emitting laser is divided into two laterally by a reflecting structure. (See Patent Document 3).
[0015]
In this example, the light emitted from the surface emitting laser is reflected by a mirror deposited with metal or the like without using a half mirror, and the light is divided into two. Then, one of the reflected light divided into two as a spatial beam using air as a medium is used for monitoring and the other is used as signal light.
[0016]
This mirror is formed by vapor-depositing a metal on a component in which a groove is formed along a specific plane direction by anisotropic wet etching or the like on a Si substrate or the like. For this reason, since light can be divided by a thin reflective structure without using a half mirror or the like, the light receiving element for monitoring can be mounted on the same substrate as the light emitting element.
[0017]
With such a configuration, while using a surface emitting laser, it is possible to divide a spatial beam in a horizontal direction with a small number of parts, and to reduce the thickness.
[0018]
[Patent Document 1]
USP5,771,254 (front page)
[0019]
[Patent Document 2]
USP5,761,299 (front page)
[0020]
[Patent Document 3]
JP 2002-72025 A (Page 1-5, FIG. 1)
[0021]
[Problems to be solved by the invention]
As described above, when trying to realize an optical module equipped with a means for monitoring emitted light by a conventional method using a half mirror, such as USP 5,771,254, USP 5,761,299, etc., in particular, a plurality of surface emitting types When manufacturing an optical module in which lasers are arrayed, the number of components such as mirrors and lenses increases.
[0022]
In addition, due to this, there is a problem that the assembly is complicated and the cost is increased. In addition, there is a problem that it is difficult to achieve high integration of components, which hinders miniaturization of the optical module.
[0023]
Furthermore, in the configuration disclosed in Japanese Patent Laid-Open No. 2002-72025, it is difficult to produce a reflective structure for separating light. That is, when the light reflecting structure is made, it is necessary to accurately form the reflecting surface, so that the etching process becomes extremely difficult. Therefore, there is a problem that the cost is high and it is not suitable for mass production.
[0024]
Accordingly, an object of the present invention is to form a small and thin optical module with a small number of components, and further, an optical waveguide component made of a transparent solid medium that divides the light emitted from the light emitting element into two is formed as an integrally molded component such as plastic. Thus, it is an object to provide an optical module that is easy to assemble and has high productivity.
[0025]
[Means for Solving the Problems]
In order to achieve the above object, according to one aspect of the present invention, a light-emitting element and a light-receiving element mounted on a substrate, a first surface on which light from the light-emitting element is incident, and incident light are different from each other. Second and third surfaces that deflect in the direction, a fourth surface that emits the first light deflected by the second surface, and a fifth surface that deflects the second light deflected by the third surface again. And a sixth surface for emitting the third light deflected by the fifth surface to the light receiving element, and a cross-sectional area of the solid medium along the traveling direction of the first light and the second light And an optical waveguide component made of a transparent solid medium that continuously decreases.
[0026]
As described above, the configuration in which the cross-sectional area of the solid medium continuously decreases along the traveling direction of the first and second lights increases the condensing action of the first and second lights, thereby further increasing the light receiving element. And the coupling efficiency with the optical fiber increases.
[0027]
Another aspect of the present invention is that the optical waveguide component is an integrally molded component such as plastic, so that assembly is simplified and mass productivity is improved.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. However, the protection scope of the present invention is not limited to the following embodiments, but extends to the invention described in the claims and equivalents thereof.
[0029]
FIG. 1 is a diagram showing an example of an optical module according to the present invention. FIG. 1A is a cross-sectional view of the optical module, and FIG. 1B is a perspective view of the optical module.
[0030]
First, the light emitting element 2 and the light receiving element 3 are mounted on a substrate, and the optical waveguide component 1 made of a transparent solid medium is fixed on the light emitting element 2 and the light receiving element 3 with a jig (not shown).
[0031]
The light emitted from the light emitting element 2, for example, the surface light emitting element, first enters the first surface 10 of the optical waveguide component 1 made of a transparent solid medium. At this time, in order to obtain high optical coupling, it is desirable that the area of the first surface 10 is larger than the light emitting area of the light emitting element.
[0032]
Thus, the light incident on the optical waveguide component made of a transparent solid medium is deflected by the second surface 11 and the third surface 12 provided on the optical waveguide component. Here, the light deflected on the second surface 11 is referred to as first light, and the light deflected on the third surface 12 is referred to as second light.
[0033]
First, when the first light propagates from the second surface 11 to the fourth surface 13, the cross-sectional area of the optical waveguide component made of a transparent solid medium continuously decreases. Since the waveguide is narrowed in a tapered shape, the light is condensed and the attenuation of light intensity can be suppressed.
[0034]
And the 1st light radiate | emitted from the 4th surface 13 of the optical waveguide component 1 is optically coupled with the core part 5 of the optical fiber 4, for example, and propagates an optical signal. At this time, if the area of the fourth surface 13 is smaller than the area of the core portion 5 of the optical fiber, most of the light emitted from the fourth surface 13 can be incident on the core portion 5. Can be raised.
[0035]
Similarly, when the second light also propagates from the third surface 12 to the fifth surface 14, the cross-sectional area of the optical waveguide component 1 made of a transparent solid medium continuously decreases. The attenuation of the light intensity is suppressed, and the light is deflected again by the fifth surface 14 to become third light.
[0036]
Then, the third light is emitted from the sixth surface 15 of the optical waveguide component, efficiently enters the light receiving element 3 mounted on the same substrate as the light emitting element 2, and the intensity thereof is monitored. At this time, if the area of the sixth surface 15 is smaller than the light receiving diameter of the light receiving element 3, most of the light emitted from the sixth surface can be incident on the light receiving portion, thereby further increasing the coupling efficiency. Can do. The monitored light is fed back to the surface light emitting element 2 so that the intensity is stabilized at a desired value.
[0037]
Usually, the ratio of the light divided by the second surface 11 and the third surface 12 described above is such that the first light deflected by the second surface 11 is about 95% of the total light emission, The remaining second light deflected by the surface 12 is about 5%.
[0038]
FIG. 6 is a diagram illustrating an example of a method for controlling the ratio of light to be divided. In this example, it is assumed that all the light incident from the first surface 10 is incident on the second surface 11 and the third surface 12. FIG. 6A shows a case where the area 11a of the second surface 11 and the area 12a of the third surface 12 are the same area. In this case, the divided light amounts are the same and are 50%.
[0039]
However, when the area 11b of the second surface 11 and the area 12b of the third surface 12 are different as shown in FIG. 6B, the amount of light divided by the ratio of the area 11b and the area 12b The amount of light to be divided increases as the area increases. Therefore, in the case shown in FIG. 6B, since the area of the second surface 11 is large, the amount of light to be deflected is large. As described above, when all the emitted light is incident on the second surface 11 and the third surface 12 of the optical waveguide component 1, the ratio of the areas of the second surface 11 and the third surface 12 is changed. By doing so, the amount of light to be split can be controlled. Since the amount of light for monitoring does not need that much, the amount of light deflected by the third surface 12 may be small.
[0040]
From the above configuration, the optical module in the present embodiment can be obtained. Next, the optical waveguide component made of a transparent solid medium in the embodiment of the present invention will be described in detail below. This optical waveguide component made of a transparent solid medium can be applied to other than the above-described optical module.
[0041]
An optical waveguide component made of a transparent solid medium is made of a material such as plastic or low-melting glass, and is poured into a mold and integrally formed in a molten state. Since such a forming method is used, complicated optical axis alignment and difficult etching are not required as in the prior art, and extremely precise optical waveguide components can be easily and mass-produced.
[0042]
In addition, although it is a single component, the cross-sectional area continuously decreases toward the light exit surface or toward the light deflection surface, so that the condensing function works and the signal light is efficiently transmitted to an optical fiber or other transmission medium. In addition to being able to enter well, it can also efficiently enter the light receiving element for monitoring.
[0043]
FIG. 2 is a cross-sectional view of an optical module on which an optical waveguide component made of a transparent solid medium having a convex lens is mounted. As shown in FIG. 2, the light coupling efficiency can be further increased by providing lenses on the entrance surface and exit surface of the optical waveguide component made of this transparent solid medium.
[0044]
For example, the coupling efficiency of incident light can be increased by providing the convex lens 7 on the first surface on which light from the surface light emitting element is incident. Furthermore, if the convex lens 8 is provided on the fourth surface, which is the light exit surface, the coupling efficiency with the optical fiber is increased, and if the convex lens 9 is provided on the sixth surface, the coupling efficiency with the light receiving element 3 is increased. Rises.
[0045]
FIG. 3 is a perspective view of an optical module in which a plurality of optical waveguide components 1 made of a transparent solid medium are arranged in parallel. As shown in FIG. 3, the optical waveguide component made of a transparent solid medium can be applied to an array structure in which a plurality of light emitting elements 2 and light receiving elements 3 are arranged in parallel on the same substrate. It is. Assembling can be facilitated by providing a plurality of sets of optical waveguide components 1 made of a transparent solid medium shown in FIG. 1 (b) and connecting them at one part to a single solid medium.
[0046]
Here, it is desirable that the adjacent continuous portion of the transparent solid medium is the side surface of the first surface 10. This is because, in the vicinity of the first surface 10, even though it is optically connected to the adjacent transparent medium, it is a region where the spread of incident light from the light emitting element is small, so that light leaks to the adjacent transparent solid medium. This is because no occurrence occurs. And it is desirable to isolate | separate the optical waveguide part in which the cross-sectional area of each optical waveguide component reduces continuously in a comb-tooth shape.
[0047]
FIG. 4 is a diagram showing an optical module using a support made of a second transparent solid medium. As shown in FIG. 4A, in order to reinforce and support the mechanical strength of the optical waveguide component, if the optical waveguide component 1 made of a transparent solid medium is used as the first solid medium, its upper surface ( (Not shown) or a support 6 made of a second transparent solid medium may be provided on the lower surface.
[0048]
Here, the first solid medium and the second solid medium may be one part physically coupled or may be separate parts. However, in order to maintain the performance of the optical waveguide component 1 made of the first transparent solid medium, the support 6 made of the second transparent solid medium has a lower refractive index than that of the first transparent solid medium. It is desirable.
[0049]
Further, as shown in FIG. 4B, the optical waveguide component 1 made of this transparent solid medium has a structure for fixing an optical fiber, for example, a structure 21 having a V groove 20 formed thereon. You may have in the vicinity on the extension of a surface.
[0050]
Alternatively, the support 6 made of the second transparent solid medium described above has a structure for fixing the optical fiber, for example, the structure 21 having the V-groove 20 formed in the vicinity of the extension of the fourth surface. You may have.
[0051]
By adopting such a configuration, it becomes unnecessary to separately prepare a fiber fixing component, and the optical axis alignment between the fourth surface and the optical fiber is facilitated.
[0052]
The exemplary embodiments are summarized as follows.
[0053]
(Appendix 1) An optical waveguide component made of a transparent solid medium,
A first surface on which light is incident;
Second and third surfaces for deflecting the incident light in two different directions;
A fourth surface for emitting the first light deflected by the second surface;
A fifth surface for again deflecting the second light deflected by the third surface;
A sixth surface for emitting third light deflected by the fifth surface,
An optical waveguide component, wherein a cross-sectional area of the solid medium continuously decreases along a traveling direction of the first light and the second light.
[0054]
(Appendix 2) In Appendix 1,
The optical waveguide component is a molded body of plastic or low-melting glass.
[0055]
(Additional remark 3) The light emitting element and light receiving element which were mounted on the board | substrate,
A first surface on which light from the light emitting element is incident; a second and third surfaces that deflect the incident light in two different directions; and a first light that is deflected on the second surface. A fourth surface, a fifth surface for deflecting the second light deflected by the third surface again, and a sixth surface for emitting the third light deflected by the fifth surface to the light receiving element. And an optical waveguide component made of a transparent solid medium in which a cross-sectional area of the solid medium continuously decreases along the traveling direction of the first light and the second light. And optical module.
[0056]
(Appendix 4) In Appendix 3,
An optical module, wherein at least one of the first surface, the fourth surface, and the sixth surface has a convex lens shape.
[0057]
(Appendix 5) In Appendix 3 or Appendix 4,
Furthermore, the optical waveguide component made of the transparent solid medium has a recess for fixing an optical fiber coupled with light emitted from the fourth surface.
[0058]
(Appendix 6) In any one of Appendices 3 to 5,
An optical module, wherein a plurality of optical waveguide components made of a transparent solid medium are arranged in parallel in the direction of emitted light, and the plurality of components are integrally formed.
[0059]
(Appendix 7) In any one of Appendices 3 to 6,
Furthermore, the optical waveguide component made of the transparent solid medium has a support made of a transparent solid medium having a lower refractive index than that of the component.
[0060]
(Appendix 8) In any one of Appendices 3 to 7,
An optical module, wherein the optical waveguide component is a molded body of plastic or low-melting glass.
[0061]
【The invention's effect】
As described above in detail, the optical module according to the present embodiment has a light emitting element and a light receiving element mounted on the same substrate, and is further provided with an optical waveguide component made of one transparent solid medium. The optical module having the means can be easily assembled.
[0062]
In addition, all of the light emitting element, the light receiving element, the optical waveguide component made of a transparent solid medium, and the optical fiber can be arranged in parallel to the substrate, and the component mountability is excellent. Further, high integration is possible, and the optical module can be reduced in size and thickness.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of an optical module according to the present invention.
FIG. 2 is a cross-sectional view of an optical module on which an optical waveguide component made of a transparent solid medium having a convex lens is mounted.
FIG. 3 is a perspective view of an optical module in which a plurality of optical waveguide components made of a transparent solid medium are arranged in parallel.
FIG. 4 is a diagram showing an optical module using a support made of a second transparent solid medium.
FIG. 5 is a diagram illustrating a configuration example of a conventional optical module.
FIG. 6 is a diagram illustrating an example of a method for controlling the ratio of light to be divided.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Optical waveguide component which consists of a transparent solid medium 2 Light emitting element 3 Light receiving element 4 Optical fiber 5 Core part 6 2nd transparent solid medium 7, 8, 9 Convex lens 10 1st surface 11 2nd surface 12 3rd Surface 13 Fourth surface 14 Fifth surface 15 Sixth surface 20 V-groove 21 Structure 100 formed with V-groove

Claims (4)

A first surface for incident light of a transparent solid medium, an optical waveguide component used in one or both of optical communication and optical information processing,
Second and third surfaces for deflecting the incident light in two different directions;
A fourth surface that is positioned in the traveling direction of the first light deflected by the second surface and emits the first light ;
A fifth surface located in the traveling direction of the second light deflected by the third surface and deflecting the second light again;
Located in the traveling direction of the third light deflected by the fifth surface, it has a sixth surface that emits the third light,
The fourth surface emits light in a direction perpendicular to the incident light, the sixth surface emits light in a direction opposite to the incident light,
Before SL first light and the second optical waveguide part cross-sectional area of the solid medium along the light traveling direction is characterized in that it condenses continuously reduced light. A light emitting element and a light receiving element mounted on the substrate,
A transparent solid medium, a first surface that incident light from the front Symbol light emitting element, a second and a third surface that deflects the two different directions light the incident, deflected by the second surface The second light is positioned in the traveling direction of the first light and is disposed in the traveling direction of the fourth surface that emits the first light and the second light deflected by the third surface. It possesses a fifth surface for deflecting again located in the traveling direction of the fifth third light deflected in terms of, and a sixth surface for emitting the third light to the light receiving element, the fourth surface is a light emitted in a direction perpendicular to the light the incident surface of the sixth light emitted in the opposite direction to the light the incident, before Symbol first light and the second An optical waveguide component in which the cross-sectional area of the solid medium continuously decreases along the light traveling direction to collect light ;
An optical module used for one or both of optical communication and optical information processing . Oite to claim 2,
An optical module, wherein a plurality of optical waveguide components made of a transparent solid medium are arranged in parallel in the direction of the emitted light, and the plurality of components are integrally formed. Oite to claim 2 or claim 3,
Furthermore, the optical waveguide component made of a transparent solid medium has a support made of a transparent solid medium having a lower refractive index than that of the component.

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