JP3295327B2 - Bidirectional optical module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bidirectional optical module for transmitting an optical signal bidirectionally using one optical fiber.

[0002]

2. Description of the Related Art In recent years, with the expansion of optical fiber communication networks,
2. Description of the Related Art Communication systems that transmit optical signals bidirectionally using one optical fiber have been increasingly introduced.

Conventionally, a bidirectional optical module used for bidirectional transmission using a single optical fiber is disclosed in
What is described in 138347 gazette is known.
FIG. 12 shows a configuration of a conventional bidirectional optical module.

In FIG. 12, reference numeral 41 denotes a semiconductor light emitting device;
42, a semiconductor light receiving element; 43, a semiconductor light receiving element for monitoring the output of the semiconductor light emitting element 41;
Reference numeral 1 denotes a heat sink on which the semiconductor light receiving elements 42 and 43 are mounted.
7 is a half mirror that transmits a part of the incident light and reflects the other, 48 is an optical fiber, 49 is a light that condenses the light emitted from the semiconductor light emitting element 41 on the optical fiber 48 and is a light that is emitted from the optical fiber 48. , A lens support for holding a lens 49, a slide ring 51 for attaching the optical fiber 48 to the lens support 50, a sealing case 52 for shielding outside air,
Reference numeral 53 denotes a ferrule which is a holding member for holding the optical fiber 48 at the center thereof, and reference numeral 54 fixes the ferrule 53 to the sealing case 52 and seals an insertion hole of the ferrule 53 of the sealing case 52. Solder seal.

In the above configuration, the light emitted from the semiconductor light emitting element 41 enters the half mirror 47, and a part of the light is reflected in a direction at 90 degrees with respect to the incident direction. At 48. The light emitted from the optical fiber 48 in the direction of the lens 49 enters the half mirror 47 via the lens 49, and a part of the light goes straight and enters the semiconductor light receiving element 42.

As described above, in the above-described conventional art, a bidirectional optical module for transmitting an optical signal bidirectionally using one optical fiber has been configured.

[0007]

However, FIG.
In the conventional bidirectional optical module shown in FIG.
4 and semiconductor light emitting element 41 mounted on carrier 45
In addition, in order to optically couple the semiconductor light receiving element 42 and the optical fiber 48, it is necessary to perform precise position adjustment of each member. In addition, the semiconductor light emitting element 41 and the semiconductor light receiving element 42 are arranged such that the light incident direction and the light
Since it is different by 0 degrees, mounting and wiring work for assembling are complicated, and furthermore, a margin of space is required for assembling adjustment, so that there is a problem that miniaturization of the module becomes difficult. .

The present invention solves the above-mentioned conventional problems, and provides a bidirectional optical module that has fewer positions for position adjustment, is easy to assemble, can be reduced in size, and is superior to the conventional one. The purpose is to do.

[0009]

In order to solve this problem, the present invention provides a half mirror in a cutting groove provided in one optical fiber, and a reflecting mirror at a position facing the tip end surface of the optical fiber. A light branching portion for condensing light in a direction perpendicular to the optical axis of the optical fiber, and a semiconductor light-emitting element and a semiconductor light-receiving element mounted on the same semiconductor substrate in a plane. A first lens and a second lens are arranged such that light emitted from the optical fiber is made incident on an optical fiber via a reflection mirror, and light emitted from the optical fiber is made incident on a semiconductor light receiving element via a half mirror. , A bidirectional optical module.

According to this configuration, the positioning of the reflecting mirror and the half mirror for coupling light to the optical fiber is performed with mechanical accuracy, and the semiconductor light emitting element and the semiconductor light receiving element are mounted on the same substrate in a plane, so that a complicated position can be obtained. The number of positions to be adjusted is reduced, and as a result, an excellent bidirectional optical module that is easy to assemble and can be downsized is obtained.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, there is provided an optical fiber having a cutting groove formed in a direction inclined with respect to a central axis, and a front end face of the optical fiber facing the optical fiber. At a position where a reflection mirror is provided obliquely with respect to the center axis of the optical fiber, a half mirror inserted and fixed in the cutting groove, and a recess provided with a mirror-like inclined surface at least at one position on the wall surface. Having a semiconductor substrate, a semiconductor light-emitting element provided in the recess, a semiconductor light-receiving element provided on the semiconductor substrate, and light emitted from the semiconductor light-emitting element to the optical fiber via the reflection mirror. A bidirectional optical module comprises a first lens for incidence, and a second lens for allowing light emitted from the optical fiber via the half mirror to enter the semiconductor light receiving element. According to this configuration, an oblique cutting groove is provided in one optical fiber, and an optical branching section can be mechanically assembled by inserting a half mirror into this groove, and the semiconductor light emitting element and the semiconductor light receiving element can be mechanically assembled. By planar mounting on the same substrate, there are few places where complicated position adjustment is performed, and as a result, assembly is easy and downsizing can be realized.

According to a second aspect of the present invention, there is provided an optical transmission system in which a groove having a width and a depth slightly larger than the outer diameter of an optical fiber is formed on one plane, and the optical fiber is inserted and fixed in the groove. An optical fiber mounting substrate made of a member, wherein a first cutting groove into which the half mirror is inserted and fixed is formed in the groove of the optical fiber mounting substrate so as to correspond to the cutting groove of the optical fiber. Since the optical fiber and the half mirror are fixed to the optical fiber mounting substrate, alignment of the optical fiber can be prevented while preventing misalignment of the optical fiber, and furthermore, the cutting groove can be easily processed and the half mirror can be firmly fixed.

According to a third aspect of the present invention, a second cutting groove inclined at approximately 45 degrees with respect to the central axis of the optical fiber is formed at a position on the optical fiber mounting substrate facing the distal end surface of the optical fiber. Since the reflecting mirror is inserted and fixed in the second cutting groove, and the mounting angle of the reflecting mirror is determined by the processing accuracy of the cutting groove, no adjustment is required, and the fixing mirror can be fixed more firmly.

According to a fourth aspect of the present invention, an inclined plane inclined at approximately 45 degrees with respect to the axis of the groove is formed on an end surface of the optical fiber mounting substrate which intersects one end of the groove for inserting and fixing the optical fiber. In addition, the reflection mirror is provided on the inclined plane, and the mounting angle of the reflection mirror is determined by the inclination angle of the inclined plane, so that angle adjustment is unnecessary, and the reflection mirror is mounted on an inclined plane larger than the reflection mirror. It can be attached, and the reflection mirror can be fixed firmly.

According to a fifth aspect of the present invention, the center of the optical fiber in the first cutting groove into which the half mirror is inserted so that the angle between the light incident on the half mirror and the reflected light is an acute angle. A reflecting portion for setting an inclination angle with respect to an axis and deflecting a traveling direction of light toward the second lens in an optical path between the half mirror and the second lens; By making the angle between the light and the light an acute angle, it is possible to suppress the polarization characteristics of the half mirror, in which the ratio of transmission and reflection changes depending on the polarization component of the incident light. The emitted light can be guided to any place.

According to a sixth aspect of the present invention, the first lens and the second lens are formed integrally with the optical fiber mounting substrate, and the mounting of the first lens and the second lens and the adjustment of the optical axis are performed. Can be eliminated, and productivity can be increased.

According to a seventh aspect of the present invention, the angle of the mirror-like inclined surface provided on the wall surface of the depression of the semiconductor substrate is set to approximately 45 degrees with respect to the surface direction of the semiconductor substrate, and the semiconductor device is mounted on the bottom surface of the depression. The semiconductor light emitting device emits light parallel to the mounting surface by reflecting the light emitted from the semiconductor light emitting element on the slope and emitting the light in a direction perpendicular to the surface of the semiconductor substrate. The element and the semiconductor light receiving element that receives light perpendicular to the mounting surface can be mounted on the same semiconductor substrate in a plane, and the mounting positions of the two elements can be accurately determined from above the semiconductor substrate. You can figure out.

[0018] The invention according to claim 8 is that the recess of the semiconductor substrate is formed by processing by anisotropic etching, and further, the slope of the recess is mirror-finished by gold plating, and the surface has a smooth inclination. Can form an accurate slope, and the light reflection ability can be increased to the utmost.

According to a ninth aspect of the present invention, an electronic circuit for controlling a semiconductor light emitting element and a semiconductor light receiving element provided on a semiconductor substrate is integrally formed on the semiconductor substrate. In addition, noise at the time of amplifying the electric signal of the semiconductor light receiving element can be reduced.

According to a tenth aspect of the present invention, the semiconductor substrate provided with the semiconductor light emitting element and the semiconductor light receiving element is provided in a sealed package shielded from the outside air, and the first lens and the second lens are sealed with each other. It is formed integrally with one wall surface of the stop package, improves the reliability of the semiconductor light emitting element and the semiconductor light receiving element by the sealing action of the sealing package, and attaches the first lens and the second lens. Is unnecessary, and the optical axis adjustment can be simplified, so that the productivity is improved.

According to an eleventh aspect of the present invention, a semiconductor substrate provided with a semiconductor light emitting element and a semiconductor light receiving element is provided in a sealed package shielded from the outside air, and one wall surface of the sealed package is attached to an optical fiber mounting substrate. Since the optical fiber mounting substrate also functions as a sealing member, an independent sealing member is not required, and the semiconductor light receiving / emitting element on the semiconductor substrate and the optical fiber, half mirror, and reflection mirror are used. By simultaneously performing the operation of adjusting the optical axis of the configured light branching unit and the operation of sealing the light receiving / emitting element, the number of operation steps can be reduced.

According to a twelfth aspect of the present invention, the semiconductor substrate is provided in a package having a plurality of electrodes, and the direction of the electrodes is substantially orthogonal to the direction of the mounting axis of the optical fiber. Since the optical fibers do not overlap each other, it is possible to prevent the optical fibers from being damaged when the electrodes are soldered.

According to a thirteenth aspect of the present invention, there is provided a holding member for holding one end of an optical fiber inserted and fixed in a groove of an optical fiber mounting substrate on a center axis thereof, and attaching the holding member to the optical fiber. It is attached to the end face of the mounting board, holding member (for example, ferrule) and other ferrule,
For example, by coupling in a precision sleeve, the bidirectional optical module can be detachably connected to another optical fiber.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In the following description, the same reference numerals in the drawings denote members having the same and substantially the same function, and a redundant description of the members will be omitted.

FIG. 1 is a cross-sectional view for explaining a configuration of a bidirectional optical module for explaining a first embodiment of the present invention. In FIG. The cut groove 3 having a width of more than 10 microns, which is inclined at 45 degrees with respect to the optical axis, transmits about 1/2 of the incident light and the other 1/2.
And is fixedly inserted into the cutting groove 2. Reference numeral 4 denotes a reflection mirror, which is provided at a position facing the distal end face 5 of the optical fiber 1 at an angle of 45 degrees with respect to the optical axis of the optical fiber 1. Reference numerals 6 and 7 denote optical lenses such as spherical lenses, 8 denotes a semiconductor substrate such as a silicon substrate, 9 denotes a depression provided in the semiconductor substrate 8, and a mirror-finished slope 10 is provided on the wall surface thereof. Reference numeral 11 denotes a semiconductor light emitting element such as a laser mounted in the depression 9 of the semiconductor substrate 8, reference numeral 12 denotes a semiconductor light receiving element such as a photodiode mounted on the surface of the semiconductor substrate 8, reference numeral 13 denotes a package in which the semiconductor substrate 8 is provided, and reference numeral 14 denotes a package. Are electrodes electrically connected to the semiconductor substrate 8 by wires 15.

In the above configuration, the light 16 emitted from the semiconductor light emitting element 11 is reflected by the mirror-like inclined surface 10 of the depression 9, travels in a direction perpendicular to the semiconductor substrate 8, and is focused by the first optical lens 6. While the optical path is 90
The optical fiber 1 is bent once and enters the optical fiber 1. The light that has traveled in the optical fiber 1 is reflected by the half mirror 3 so that about half of the light 17 is reflected and the optical path is bent by 90 degrees. It is incident on 12. Thus, it functions as a bidirectional optical module.

In the above-described structure, an optical fiber 1 is provided with an oblique cutting groove 2 and a half mirror 3 is inserted into the cutting groove 2 to mechanically assemble an optical branching portion. Element 11 and semiconductor light receiving element 12
Is mounted on the same substrate, the number of locations where complicated position adjustment is performed is reduced, and as a result, an effect is obtained that an easy assembly and a small bidirectional optical module can be realized.

In the first embodiment, the light 16 emitted from the semiconductor light emitting element 11 is condensed on the reflection mirror 4, and
The light 17 reflected by the half mirror 3 is transmitted to the light receiving element 12.
Although it has been described that each member is arranged so that light is condensed,
Similar effects can be obtained even if the positions of the semiconductor light emitting element 11 and the semiconductor light receiving element 12 are reversed. Furthermore, although the description has been made using a spherical lens as the first optical lens 6 and the second optical lens 7, any condensing lens such as an aspherical lens or a Fresnel lens can be used.

FIG. 2A is a side view for explaining a configuration of an optical branching unit in a bidirectional optical module according to a second embodiment of the present invention, and FIG. 2B is an optical branching unit of FIG. 2A and 2B, reference numeral 18 denotes an optical fiber in which a groove 19 having a width and a depth slightly larger than the outer diameter of the optical fiber 1 is formed on one plane. It is a mounting substrate and is formed of a light transmitting member such as a quartz glass or silicon substrate. The optical fiber 1 is inserted and fixed in the groove 19 of the optical fiber mounting substrate 18, and the first cutting groove 20 a having a width of about several tens of microns for inserting the half mirror 3 is formed in the optical fiber 1 on the optical fiber mounting substrate 18. It is integrally formed corresponding to the installation position of the cutting groove 2, and the first
When the cutting groove 20a is formed, the cutting groove 2 of the optical fiber 1 can be formed at the same time.

In the above configuration, the optical fiber mounting board 1
By fixing the optical fiber 1 and the half mirror 3 to the optical fiber 8, it is possible to prevent the optical fiber 1 from being misaligned and to align the optical fiber 1, and the processing of the cut grooves 2 and 20 a is easy, and the half mirror 3 is firmly fixed. The effect that it can be obtained is obtained.

In the configuration of the second embodiment shown in FIGS. 2A and 2B, the second cutting groove 20b inclined by 45 degrees with respect to the central axis of the optical fiber 1 is provided with the optical fiber mounting board 18.
Formed at a position facing the distal end face 5 of the optical fiber 1 above,
The reflecting mirror 4 is inserted and fixed in the second cutting groove 20b. With this configuration, the mounting angle of the reflecting mirror 4 can be determined by the processing accuracy of the second cutting groove 20b, and the angle can be adjusted. Is unnecessary, and the effect that the reflection mirror 4 can be firmly fixed can be obtained.

FIG. 3 is a cross-sectional view for explaining the configuration of the optical branching unit according to the third embodiment of the present invention. In FIG. 3, one end of the groove 19 for inserting and fixing the optical fiber 1 is
A surface intersecting with the end surface 21 of the optical fiber mounting substrate 18 is formed on an inclined plane 22 inclined at 45 degrees with respect to the axis of the groove 19, and the reflecting mirror 4 is bonded and fixed to the inclined plane 22. Accordingly, the mounting angle of the reflection mirror 4 is determined by the inclination angle of the inclined plane 22, so that angle adjustment becomes unnecessary, and the reflection mirror 4 can be firmly fixed by attaching the reflection mirror 4 to the inclined plane 22. The effect is obtained.

FIG. 4 is a cross-sectional view for explaining the structure of an optical branching unit according to a fourth embodiment of the present invention. In FIG. 4, the light enters the reflecting mirror 4 with respect to the base 18a of the optical fiber mounting board 18. The inclined plane 22 is provided so that the direction of the light 16 is inverted upside down from the configuration in FIG. 3. In this configuration, the point that the light 16 does not pass through the inside of the optical fiber mounting substrate 18 is that Although different from the configuration of FIG. 3, similar effects can be obtained.

In the third embodiment shown in FIG. 3, the cut groove 2 with respect to the central axis of the optical fiber 1 is formed so that the angle 23 between the light incident on the half mirror 3 and the reflected light becomes an acute angle. The angle of inclination with respect to the first cutting groove 20a is set, and the light traveling direction is set to the second optical lens in the block 18b of the optical fiber mounting substrate 18 in the optical path between the half mirror 3 and the second optical lens 7. Reflector 24 for polarization in seven directions
Is provided.

When the angle 23 between the incident light and the reflected light is large, the half mirror 3 depends on the polarization component of the incident light,
Since a problem occurs in which the ratio of the reflected light and the transmitted light changes, this configuration can suppress unnecessary polarization characteristics of the half mirror 3, and further, by providing the reflecting portion 24,
The effect is obtained that the light reflected by the half mirror 3 can be guided to an arbitrary place.

Although the reflecting section 24 has been described as a configuration in which a light reflecting surface is formed on one plane of the block 18b provided on the optical fiber mounting board 18, the reflecting section reflects light and provides an optical path in an arbitrary direction. Any member that can be controlled can be used.

In the fourth embodiment shown in FIG. 4, the direction of the light 17 emitted from the half mirror 3 is reversed from that in FIG. , The inclination angle of the reflection part 24, and the inclination angle of the cutting groove 2 of the optical fiber 1 are set.
A similar effect can be obtained with this configuration.

FIG. 5 is a sectional view for explaining the structure of an optical branching unit according to a fifth embodiment of the present invention.
The first optical lens 6 and the second optical lens 7, which are two lenses, are integrally formed with an optical fiber mounting substrate 18. With this configuration, it is not necessary to attach each optical lens and adjust the optical axis, and it is possible to obtain an effect that productivity can be improved.

In FIG. 5, two optical lenses 6, 7 are provided.
Is a spherical lens, but this optical lens may have any lens configuration or material such as an aspherical lens, a Fresnel lens, or a gradient index lens that can be integrally formed with the optical fiber mounting substrate 18.

FIG. 6 is a perspective view for explaining the configuration of a semiconductor substrate according to a sixth embodiment of the present invention. In FIG. 6, a mirror-like inclined surface 10 provided on a wall surface of a depression 9 of a semiconductor substrate 8 has: An angle of 45 degrees is formed with respect to the surface direction of the semiconductor substrate 8, and light 16 emitted from the semiconductor light emitting element 11 mounted on the bottom surface of the depression 9 is reflected by the inclined surface 10, and is perpendicular to the semiconductor substrate 8. It is configured to emit light.

With the above configuration, the semiconductor light-emitting element 11 that outputs light parallel to the mounting surface and the semiconductor light-receiving element 12 that receives light perpendicular to the mounting surface can be mounted on the same semiconductor substrate 8 by plane mounting. In addition, the mounting position of the two elements 11 and 12 can be accurately grasped from above the mounting surface of the semiconductor substrate 8.

Further, if the depression 9 of the semiconductor substrate 8 is processed by anisotropic etching and the slope 10 of the depression 9 is plated with gold, an accurate slope with a smooth inclination of the surface can be formed, and the light reflection ability can be improved. The effect of increasing to the maximum can be obtained.

FIG. 7 is a perspective view for explaining the structure of a semiconductor substrate according to a seventh embodiment of the present invention. In FIG. 7, a semiconductor light emitting element 11 and a semiconductor light receiving element 12 are mounted on a semiconductor substrate 8. For example, the semiconductor light emitting element 11
, And an integrated circuit 26 for amplifying the output of the semiconductor light receiving element 12. The semiconductor light emitting element 11, the semiconductor light receiving element 12, and each integrated circuit 2 are mounted.
Since the connection wiring with the wirings 5 and 26 can be shortened, the effect of significantly reducing the noise of the electric signal can be obtained.

Although the integrated circuits 25 and 26 have been described as a drive circuit and an amplifier circuit, respectively,
1 and a circuit for controlling the semiconductor light receiving element 12
Any circuit can be provided.

FIG. 8 is a sectional view for explaining the structure of the semiconductor light receiving element / semiconductor light emitting element portion according to the eighth embodiment of the present invention. In FIG. 8, the semiconductor light emitting element 11 and the semiconductor light receiving element 12 are mounted. The semiconductor substrate 8 is provided in a package 13 having a plurality of electrodes 14, which is sealed by a sealing plate 27 to shield from outside air, and two optical lenses 6 and 7 are integrated on the sealing plate 27. It is formed by molding.

With the above structure, the semiconductor light emitting element 11 and the semiconductor light receiving element 12 are not affected by the outside air, so that their life and reliability can be improved. There is no need to attach the two optical lenses 6 and 7 to be combined,
Since the adjustment of the optical axis can be simplified, the effect of increasing the productivity can be obtained.

The sealing plates 27 are made of light 16, 17
It is sufficient that only the optical lenses 6 and 7 through which light is transmitted are made of a light transmitting member, and the other portions are made of any material that blocks light as long as the material can seal the package 13. be able to.

FIG. 9 is a cross-sectional view for explaining the overall configuration of a bidirectional optical module according to the ninth embodiment of the present invention. In FIG. 9, a semiconductor substrate 8 on which a semiconductor light emitting element 11 and a semiconductor light receiving element 12 are mounted is shown. To a plurality of electrodes 14
The package 13 is provided in a package 13 which is sealed with an optical fiber mounting board 18 and shielded from the outside air.

With the above configuration, the optical fiber mounting board 1
8 also serves as a sealing plate of the package 13, so that an independent sealing plate as shown in FIG.
Semiconductor substrate 8, semiconductor light emitting element 11, semiconductor light receiving element 1
2 to adjust the optical axis of the light receiving / light emitting element unit composed of the optical fiber 1, the half mirror 3, and the reflecting mirror 4, and to seal the semiconductor light emitting element 11 and the semiconductor light receiving element 12. Since the stopping operation can be performed at the same time, the effect of reducing the number of operation steps can be obtained.

Further, as shown in FIG. 9, if the optical fiber mounting substrate 18 and the two optical lenses 6 and 7 are integrally formed, the operation of mounting the optical lenses becomes unnecessary, and the adjustment of the optical axis can be simplified. Is obtained.

In the configuration of the ninth embodiment, if the package 13 including the semiconductor light emitting element 11 and the semiconductor light receiving element 12 can be sealed using the optical fiber mounting board 18, the shape of the optical fiber mounting board 18, The structure is not limited to the above.

Further, in the configuration of the ninth embodiment shown in FIG. 9, the directions of the optical fiber 1 and the electrode 14 are drawn in parallel with each other for convenience, but the tenth embodiment of the present invention shown in FIG. If the configuration is such that the direction of the mounting axis of the optical fiber 1 and the direction of the electrode 14 are at right angles to each other as shown in the external perspective view showing the bidirectional optical module, the optical fiber 1 does not overlap the electrode 14. When the electrode 14 is soldered to another substrate, the effect of preventing damage to the optical fiber 1 can be obtained.

FIG. 11 is a sectional view for explaining the structure of an optical branching unit according to an eleventh embodiment of the present invention. In FIG. 11, the optical fiber 1 inserted and fixed in a groove 19 of an optical fiber mounting board 18 is shown. One end 28 is held at the center of the ferrule 29, and this ferrule 29 is
8 is attached in close contact with the end face 30.

According to the above configuration, when the ferrule 29 and the ferrule holding another optical fiber are connected, for example, in a precision sleeve, the bidirectional optical module can be detachably connected to the other optical fiber. Since the optical fiber 1 is not attached in a bare state, an effect that a bidirectional optical module that can be easily handled can be provided is obtained.

Although the ferrule 29 has been described as being attached in close contact with the end face 30 of the optical fiber mounting substrate 18, the optical fiber 1 is not exposed in a bare state between the optical fiber mounting substrate 18 and the ferrule 29. The mounting means and configuration are not limited to those described above.

[0056]

As described above, according to the bidirectional optical module of the present invention, the half mirror is provided in the cut groove provided in one optical fiber, and the reflection mirror is provided in the position facing the distal end surface. A light branching portion that couples light in a direction perpendicular to the optical axis of the optical fiber, the semiconductor light-emitting element and the semiconductor light-receiving element are mounted on the same semiconductor substrate in a plane, and emitted from the semiconductor light-emitting element. By arranging two optical lenses so that light enters the optical fiber via the reflection mirror and light emitted from the optical fiber enters the light receiving element via the half mirror, a bidirectional optical module is constructed. In addition, the positioning of the reflection mirror and the half mirror for condensing light on the optical fiber can be performed with mechanical accuracy, and the semiconductor light emitting element and the semiconductor light receiving element are mounted on the same substrate. The by surface mounting, the less locations to perform complicated position adjustment, so that the assembly is facilitated, it is possible to realize miniaturization.

Further, by fixing the optical fiber and the half mirror to the optical fiber mounting substrate, it is possible to prevent the optical fiber from being misaligned and to align the optical fiber, to facilitate the processing of the cut groove, and to firmly fix the half mirror. be able to.

Further, since the semiconductor light emitting element and the semiconductor light receiving element can be mounted on the same semiconductor substrate in a plane, the mounting positions of the two elements can be accurately grasped from above the semiconductor substrate. .

Further, if the depression of the semiconductor substrate is processed by anisotropic etching and the slope of the depression is plated with gold,
It is possible to form an accurate slope with a smooth inclination of the surface, and the light reflection efficiency is improved.

Further, by integrally forming the two optical lenses on the sealing plate, the semiconductor light emitting element and the semiconductor light receiving element can be prevented from being affected by the outside air.
The life and reliability can be improved, and the work of mounting two optical lenses that are optically coupled to the semiconductor light emitting element and the semiconductor light receiving element becomes unnecessary, and the adjustment of the optical axis can be simplified, so that the productivity can be increased.

Further, by sealing the package with an optical fiber mounting substrate formed integrally with the two optical lenses, an independent sealing plate is not required, and the package is composed of an optical fiber, a half mirror and a reflection mirror. Since the operation of adjusting the optical axis of the light branching unit and the installation part of the light receiving element and the light emitting element to each other and the operation of sealing the installation part of the light receiving element and the light emitting element can be performed at the same time, the number of work steps is reduced. Also, the work of mounting the two optical lenses is not required, and the work of adjusting the optical axis is simplified.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a bidirectional optical module for explaining a first embodiment of the present invention.

FIGS. 2A and 2B are a side view and a cross-sectional view illustrating a configuration of an optical branching unit in a bidirectional optical module according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a configuration of an optical branching unit in a bidirectional optical module according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a configuration of an optical branching unit in a bidirectional optical module according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of an optical branching unit in a bidirectional optical module according to a fifth embodiment of the present invention.

FIG. 6 is a perspective view illustrating a configuration of a semiconductor substrate in a bidirectional optical module according to a sixth embodiment of the present invention.

FIG. 7 is a perspective view illustrating a configuration of a semiconductor substrate in a bidirectional optical module according to a seventh embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating a configuration of a semiconductor light receiving element / semiconductor light emitting element portion in a bidirectional optical module according to an eighth embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating an overall configuration of a bidirectional optical module according to a ninth embodiment of the present invention.

FIG. 10 is an external perspective view of a bidirectional optical module according to a tenth embodiment of the present invention.

FIG. 11 is a sectional view illustrating a configuration of an optical branching unit in a bidirectional optical module according to an eleventh embodiment of the present invention.

FIG. 12 is a partial cross-sectional view illustrating a configuration of a conventional bidirectional optical module.

[Explanation of symbols]

1: optical fiber, 2, 20a, 20b: cutting groove, 3
... half mirror, 4: reflection mirror, 5: tip of optical fiber, 6, 7 ... optical lens, 8 ... semiconductor substrate,
9: recess, 10: mirror-like slope, 11: semiconductor light emitting element, 12: semiconductor light receiving element, 13: package, 14: electrode, 15: wire, 16, 17 ...
Light, 18 ... Optical fiber mounting board, 19 ... Groove, 2
Reference Signs List 1, 30: end face of optical fiber mounting board, 22: inclined plane, 23: angle between incident light and reflected light, 24: reflection part, 25: integrated circuit for driving semiconductor light emitting element, 2
6. Integrated circuit for amplifying the output of semiconductor light receiving element 27
... seal plate 28 ... one end of optical fiber 29 ...
Ferrule.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-10354 (JP, A) JP-A-9-181676 (JP, A) JP-A-7-202351 (JP, A) JP-A-6-202351 338090 (JP, A) JP-A-59-39084 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 6/42

Claims (13)

(57) [Claims] 1. An optical fiber having a cutting groove formed in a direction inclined with respect to a central axis, and a position oblique to the central axis of the optical fiber at a position facing a distal end surface of the optical fiber. A semi-mirror inserted and fixed in the cutting groove, a semiconductor substrate having a concave portion provided with a mirror-like inclined surface in at least one portion of a wall surface, and a semiconductor light emitting device provided in the concave portion. An element, a semiconductor light receiving element provided on the semiconductor substrate, a first lens for causing light emitted from the semiconductor light emitting element to enter the optical fiber via the reflection mirror, and A bi-directional optical module, comprising: a second lens that causes light emitted through the half mirror to enter the semiconductor light receiving element. 2. An optical fiber mounting substrate comprising a light transmitting member in which a groove having a width and a depth slightly larger than the outer diameter of the optical fiber is formed on one plane, and the optical fiber is inserted and fixed in the groove. The first cutting groove, into which the half mirror is inserted and fixed, is formed in the groove of the optical fiber mounting substrate so as to correspond to the cutting groove of the optical fiber. Bidirectional optical module. 3. A second cutting groove inclined at approximately 45 degrees with respect to the central axis of the optical fiber is formed at a position facing the distal end surface of the optical fiber on the optical fiber mounting substrate, and the second cutting groove is formed. The bidirectional optical module according to claim 2, wherein the reflection mirror is inserted and fixed in the groove. 4. An inclined plane inclined at approximately 45 degrees with respect to the axis of the groove is formed on an end surface of the optical fiber mounting substrate that intersects one end of the groove for inserting and fixing an optical fiber. The bidirectional optical module according to claim 2, wherein the reflection mirror is provided. 5. An inclination angle of the first cutting groove into which the half mirror is inserted with respect to a central axis of the optical fiber is set so that an angle formed between light incident on the half mirror and reflected light thereof is an acute angle. 3. The bidirectional optical module according to claim 2, further comprising a reflecting portion for changing a traveling direction of light toward the second lens in an optical path between the half mirror and the second lens. 6. The bidirectional optical module according to claim 2, wherein the first lens and the second lens are formed integrally with the optical fiber mounting substrate. 7. An angle of a mirror-like inclined surface provided on a wall surface of a dent of a semiconductor substrate is set to approximately 45 degrees with respect to a surface direction of the semiconductor substrate, and light is emitted from a semiconductor light emitting element mounted on a bottom surface of the dent. 2. The bidirectional optical module according to claim 1, wherein the light is reflected by the slope and emitted in a direction perpendicular to the surface of the semiconductor substrate. 8. The bidirectional optical module according to claim 7, wherein the recess of the semiconductor substrate is formed by processing by anisotropic etching, and further, the slope of the recess is gold-plated to have a mirror surface. 9. The bidirectional optical module according to claim 1, wherein an electronic circuit for controlling the semiconductor light emitting element and the semiconductor light receiving element provided on the semiconductor substrate is integrally formed on the semiconductor substrate. 10. A semiconductor substrate provided with a semiconductor light emitting element and a semiconductor light receiving element is provided in a sealed package shielded from the outside air, and the first lens and the second lens are provided on one wall surface of the sealed package. The bidirectional optical module according to claim 1, wherein the optical module is formed integrally. 11. A semiconductor substrate provided with a semiconductor light emitting element and a semiconductor light receiving element is provided in a sealed package shielded from the outside air, and one wall surface of the sealed package is formed by an optical fiber mounting substrate. The bidirectional optical module according to claim 2. 12. The bidirectional light according to claim 1, wherein the semiconductor substrate is provided in a package having a plurality of electrodes, and the direction of the electrodes is substantially orthogonal to the direction of the mounting axis of the optical fiber. module. 13. A holding member for holding one end of an optical fiber inserted and fixed in the groove of the optical fiber mounting board on a central axis of the optical fiber, and holding the holding member to an end face of the optical fiber mounting board. 3. The bidirectional optical module according to claim 2, wherein the optical module is attached to the optical module.