JPH0954228A - Optical transmission module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the man-hours for assembly and the yield for assembly by providing the above module with a reflection surface for changing the optical axis of an optical fiber and setting the position of a fixing surface at a position where the fixing surface does not enter the underside of a semiconductor photodetector. SOLUTION: A V-groove 4 is composed of two parts varying in width and depth. Namely, the part where the width of the V-groove 4 is wider and the depth is deeper is the fixing part 9 of the optical fiber 3. The part of the V-groove 4 on the side near the front end side than the fixing part 9 is an optical axis converting part 10 formed to the narrow width and the deep width. The fixing surface 11 for determining the position at the front end of the optical fiber 3 is formed in the boundary part between the fixing part 9 and the optical axis converting part 10. The position of the fixing surface 11 is set at the position where the surface does not enter the underside of the semiconductor photodetector 5. The light radiated from the end face of the optical fiber 3 is reflected at a reflection surface 12 disposed at the front end of the V-groove 4. This light is detected by the semiconductor photodetector 5 disposed on the optical axis converting part 10 of the V-groove 4 of the Si substrate 2 and is converted by photoelectric conversion to an electric signal, which is amplified by an amplifier 6 and is outputted from a terminal 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a planar mount optical receiver module for high speed optical communication.

[0002]

2. Description of the Related Art Conventionally, as a technique of an optical receiver module in such a field, there is "AT &T" 131-Type w ".
Some of them are disclosed in the technical data of "it Integrated Pre-Amp". 3A and 3B are explanatory views showing a configuration example of the conventional optical receiving module disclosed in the above document, FIG. 3A is an exploded perspective view, FIG. 3B is a side sectional view of a light receiving portion, and FIG. 4) is a front sectional view of a portion for fixing an optical fiber.

In the figure, 51 is an optical receiver module,
The light receiving module 51 includes a semiconductor light receiving element 52 and a Si substrate 5 on which a V groove 54 for mounting an optical fiber 53 is formed.
5. From a terminal 58 having a package 57 for accommodating the Si substrate 55 and the preamplifier 56, an output terminal for outputting an electric signal, a power supply terminal for supplying power to the semiconductor light receiving element 52 and the preamplifier 56. Composed.

As shown in FIG. 3 (c), the V groove 54 has a depth into which the entire optical fiber 53 is inserted.
Positioning can be performed by abutting the tip of the optical fiber 53 on the inclined surface of the tip of the groove. Also, with this slope as a reflecting surface, the light emitted from the optical fiber 53 is reflected,
Semiconductor light receiving element 52 in which the light is mounted on a Si substrate 55
It is designed to enter. Here, the optical fiber 53
In order to shorten the distance from the tip to the semiconductor light receiving element 52, the tip of the optical fiber 53 is fixed at a position where it enters below the semiconductor light receiving element 52.

[0005]

However, in the above-mentioned conventional optical receiving module, since the tip of the optical fiber enters under the semiconductor light receiving element, the semiconductor optical element is mounted on the Si substrate and then the optical fiber is mounted. If you try, you cannot confirm the position of the tip of the optical fiber.
There is a problem that the semiconductor light receiving element is damaged at the tip of the optical fiber or the tip of the optical fiber is damaged.

Further, since the position of the tip of the optical fiber cannot be confirmed, there is a problem that the optical fiber is not fixed at the proper position and the coupling efficiency is lowered. Further, if the optical fiber is first mounted, there is a problem that the reliability of fixing the optical fiber is deteriorated by the heat applied when mounting the semiconductor light receiving element.

[0007]

In order to solve the above-mentioned problems, the present invention fixes an optical fiber in a V groove formed in a substrate and forms a reflecting surface at the tip of the V groove to form an optical fiber. In an optical receiving module for converting an axis and inputting light to a semiconductor light receiving element mounted on the substrate, the V groove is composed of two parts having different shapes, and the tip of the optical fiber is fixed to a boundary part having different shapes. A surface is formed, and a reflection surface for converting the optical axis of the optical fiber is provided in a portion of the V-groove on the tip side of the fixed surface, and the fixed surface is positioned so as not to go under the semiconductor light receiving element. In addition, the depth of the portion of the V groove where the optical fiber is fixed is V for the entire optical fiber.
It is a depth that does not enter the groove.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing a first embodiment of an optical receiving module of the present invention, FIG. 1 (a) is an exploded perspective view, and FIG. 1 (c) is a side cross section of a light receiving portion. It is a figure. In the figure, reference numeral 1 denotes an optical receiving module, which is an optical receiving module 1.
Has the following configuration.

Reference numeral 2 is a Si substrate, and a V groove 4 for fixing the optical fiber 3 is provided on the Si substrate 2. 5
Is a semiconductor light receiving element, and a light incident surface is provided on the back surface,
It is mounted on the Si substrate 2 so that the incident surface is located at a predetermined position on the V groove 4. 6 is a preamplifier, and the preamplifier 6 and the Si substrate 2 are housed in a package 7. The package 7 is provided with a terminal 8 including an output terminal for outputting an electric signal, and a power supply terminal for supplying power to the semiconductor light receiving element 5 and the preamplifier 6.

Next, the shape of the V groove 4 will be described. 2A and 2B are explanatory views showing the first embodiment of the V groove, FIG. 2A is a plan view, FIG. 2B is a side sectional view, and FIG.
Is a front sectional view. As shown in FIG. 2, the V groove 4 is composed of two portions having different widths and depths.

That is, the wide and deep portion of the V-groove 4 serves as the fixing portion 9 of the optical fiber 3, and the tip end side of the V-groove 4 has a narrower width and a shallower optical axis conversion. Part 1
0, and a fixed surface 11 that determines the position of the tip of the optical fiber 3 is formed at the boundary between the fixed portion 9 and the optical axis conversion portion 10. The position of the fixed surface 11 is set so as not to go under the semiconductor light receiving element 5.

Here, the width of the fixing portion 9 of the V-groove 4 is not such a depth that the entire optical fiber 3 enters the V-groove 4, but the depth that the core 3a of the optical fiber 3 extends into the V-groove 4. It has such a width. For example, the optical fiber 3 has a core diameter of 10
In the case of a single mode optical fiber having a μm and a cladding diameter of 125 μm, if the width of the fixed portion 9 of the V groove 4 is 180 μm, the depth of the optical fiber 3 entering the V groove 4 is 81 μm, and the entire optical fiber 3 is V Does not enter groove 4.

The width of the optical axis converter 10 is about half that of the fixed portion 9, so that the optical axis converter 10 and the fixed portion 9 are separated.
The optical fiber 3 abuts on the slope of the boundary of the optical fiber 3, whereby the fixing surface 11 of the optical fiber 3 can be formed, and the light emitted from the optical fiber 3 can pass through the optical axis converter 10. Then, an inclined surface is formed at the tip of the optical axis conversion unit 10, and this inclined surface is used as the reflection surface 12 to form the optical fiber 3
The optical axis of the light radiated from is converted to the surface direction of the Si substrate 2. The semiconductor light receiving element 5 is mounted on the Si substrate 2 so that a light incident surface (not shown) provided on the back surface of the semiconductor light receiving element 5 is on the reflecting surface 12 of the V groove 4.

The operation of the optical receiving module according to the first embodiment described above will be described below. The light emitted from the end surface of the optical fiber 3 is reflected by the reflecting surface 12 provided at the tip of the V groove 4.
Reflected by the optical axis conversion unit 1 of the V groove 4 of the Si substrate 2
The light is received by the semiconductor light receiving element 5 provided on the surface 0. Then, the semiconductor light receiving element 5 performs photoelectric conversion to convert the optical signal into an electric signal, which is amplified by the preamplifier 6 and output from the terminal 8.

According to the above construction, the optical fiber 3 is fixed by the fixing portion 9 of the V groove 4, and the tip of the optical fiber 3 is formed at the boundary portion between the fixing portion 9 of the V groove 4 and the optical axis converting portion 10. Since the optical fiber 3 and the semiconductor light receiving element 5 can be coupled to each other without adjustment, the optical fiber 3 and the semiconductor light receiving element 5 can be coupled to each other without adjustment. Further, without using a lens, the inclined surface at the tip of the V groove 4 is used as a reflecting surface 12 for optical axis conversion, and the light emitted from the end surface of the optical fiber 3 is reflected by the reflecting surface 12, and the light is V groove 4. Since the structure is such that light is received by the semiconductor light receiving element 5 on the Si substrate 2 provided with, the light receiving module can be made small and thin.

Here, in the optical receiver module of the first embodiment of the present invention, the width of the fixing portion 9 of the V groove 4 is determined so that the entire optical fiber 3 does not enter the V groove 4. At this time, since the entire core 3a of the optical fiber 3 is located at a position lower than the incident surface of the bottom surface of the semiconductor light receiving element 5 and the radiation pattern from the optical fiber 3 hits the reflecting surface 12, the reflecting surface 12 To semiconductor light receiving element 5
The distance from the tip of the optical fiber 3 to the incident surface of the semiconductor light receiving element 5 is reduced even if the tip of the optical fiber 3 is retracted to a position where it does not enter under the semiconductor light receiving element 5. If the optical fiber 3 is a single-mode optical fiber having a core diameter of 10 μm and a cladding diameter of 125 μm, the distance from the end surface of the optical fiber 3 to the incident surface of the semiconductor light receiving element 5 is 140 to 170.
μm, which is the same as the conventional one in which the tip of the optical fiber is inserted under the semiconductor light receiving element 5.

Further, since the tip of the optical fiber 3 is fixed at the exposed position without entering under the semiconductor light receiving element 5, the assembly becomes easy. That is, after mounting the semiconductor light receiving element 5 on the Si substrate 2, the position of the tip of the optical fiber 3 is confirmed and the optical fiber is fixed. The optical fiber 3 is not fixed at the position of and the coupling efficiency does not decrease. Furthermore, since the optical fiber 3 is fixed after the position of the tip of the optical fiber 3 is confirmed, the assembly accuracy is improved and the allowable assembly range is improved.

[0018]

As described above, according to the present invention, the V groove formed on the substrate for fixing the optical fiber is composed of two portions having different shapes, and the optical fiber tip is provided at the boundary portion having the different shape. And a reflecting surface for converting the optical axis of the optical fiber is provided in the portion of the V groove on the tip side of this fixing surface, and the position of the fixing surface is set so as not to go under the semiconductor light receiving element. Therefore, after mounting the semiconductor light receiving element on the substrate, the position of the tip of the optical fiber can be confirmed and the optical fiber can be fixed. The optical fiber is not fixed and the coupling efficiency does not decrease. Furthermore, since the optical fiber is fixed after the position of the tip of the optical fiber is confirmed, the assembly accuracy is improved,
The allowable assembly range is improved, which can be expected to improve the assembly man-hour and the assembly yield.

Further, since the depth of the V groove is set so that the entire optical fiber does not enter, the distance from the reflecting surface at the tip of the V groove to the semiconductor light receiving element can be shortened, whereby the tip of the optical fiber is placed at the semiconductor light receiving element. Even if it is retracted to a position where it does not enter below, the distance from the end face of the optical fiber to the semiconductor light receiving element can be shortened, and the coupling efficiency does not decrease.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a first invention of an optical receiver module of the present invention.

FIG. 2 is an explanatory view showing a first embodiment of a V groove.

FIG. 3 is an explanatory diagram of a conventional optical receiver module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical receiving module 2 Si substrate 3 Optical fiber 4 V groove 5 Semiconductor light receiving element 9 Fixed part 10 Optical axis conversion part 11 Fixed surface 12 Reflective surface

Claims (2)

[Claims] 1. An optical fiber is fixed to a V groove formed on a substrate, a reflecting surface is formed at the tip of the V groove to convert the optical axis of the optical fiber, and the semiconductor light receiving element mounted on the substrate receives an optical signal. In the optical receiving module for inputting, the V groove is composed of two parts having different shapes, the fixing surface of the optical fiber tip is formed at a boundary portion having a different shape, and the portion of the V groove on the tip side of the fixing surface. An optical receiving module, characterized in that a reflecting surface for converting the optical axis of the optical fiber is provided on the optical fiber, and the fixed surface is positioned so as not to go under the semiconductor light receiving element. 2. The optical receiving module according to claim 1, wherein the depth of the portion of the V-groove where the optical fiber is fixed is such that the entire optical fiber does not enter the V-groove. module.