JPH06208041A - Optical module - Google Patents

Abstract

PURPOSE:To obtain the optical module which generates a stable light output and good in assembly even if the assembly position precision varies. CONSTITUTION:The light emitted by a light emitting element 1 is reflected in an obliquely polished rod lens 2. The light propagated in the obliquely polished rod lens 2 is converged and inputted to an optical fiber 3. The obliquely polished surface of the obliquely polished rod lens 2 reflects the light output of the light emitting element 1 and converges it into an optical fiber, so the assembly position precision of a prism never deviates and the stable light output is obtained. The obliquely polished rod lens 2 is only positioned after the optical fiber 3 and light emitting element 1 are previously positioned, so the optical transmission module which is good in assembly is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module for optical communication.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a conventional optical module, in which 3 is an optical fiber, 5 is a prism, 6 is a rod lens, and 7 is an optical element. Prism 5
The rod lens 6 and the rod lens 6 are fixed to the metal block by soldering.

Next, the operation will be described. The optical element 7 and the optical fiber 3 are connected by a prism 5 that converts the direction of the optical path L and an optical path that passes through a rod lens 6 that collects light according to a refractive index distribution.

In the case of the optical transmission module, the light output from the optical element 7 is reflected in the prism 5 and the rod lens 6
Entered in. The light input to the rod lens 6 is condensed and input to the optical fiber 3.

In the case of the optical receiving module, the light input from the optical fiber 3 is input to the rod lens 6. The light input to the rod lens 6 is condensed and input to the prism 5. The light input to the prism 5 is reflected in the prism 5 and its optical axis is converted, and then input to the optical element 7.

[0006]

Since the conventional optical module is constructed as described above, the positional accuracy is deviated when the rod lens 6 and the prism 5 are fixed, and a gap is formed between the rod lens 6 and the prism 5. Occurs, and multiple reflection of light occurs at the end surface of the rod lens 6 and the end surface of the prism 5,
There is a problem that the transmission characteristics are not stable.

Further, in the conventional optical module, the light reflected by the plane of the prism 5 on the optical element 7 side is not directly input to the optical element, or the light reflected by the surface of the optical element 7 is not directly input to the prism 5. The optical axis and the prism 5
The angle formed by the plane and the angle formed by the optical axis with the surface of the optical element 7 must be kept at an angle other than a right angle. As a result, when the optical fiber 3 is fixed, the method of adjusting the optical axis between the optical fiber 3 and the optical element 7 at the time of assembly is such that the rod lens 6 and the prism 5 are finely moved in the X, Y, and Z directions, respectively, and positioned at the same time. The element 7 needs to be finely moved in the X and Z directions to be positioned, resulting in poor assembly.

The present invention has been made in order to solve the above problems, and it is possible to obtain a stable transmission characteristic without shifting the positional accuracy of the prism and at the same time to obtain an optical module having a good assembling property. Has an aim.

[0009]

The optical module according to the present invention is such that the rod lens also functions as a prism by obliquely polishing one end of the rod lens and the curved surface of the side surface of the rod lens prevents reflected light. is there.

[0010]

In the optical module according to the present invention, since the rod lens also functions as a prism, stable optical output can be obtained without shifting the positional accuracy.

Further, in the optical module according to the present invention, since the rod lens has a cylindrical shape, even if the angle formed by the optical axis of the optical element and the rod lens is a right angle, the side surface of the rod lens has a cylindrical shape. Light reflected by the side surface of the lens is dispersed and is not input to the optical element.

[0012]

【Example】

Example 1. FIG. 1 is a block diagram showing an optical transmission module according to the present invention. In the figure, 1 is a light emitting element, 2 is an obliquely polished rod lens, and 3 is an optical fiber.

Next, the operation will be described. The light output from the light emitting element 1 is reflected in the oblique polishing rod lens 2. The light passing through the oblique polishing rod lens 2 is condensed and input to the optical fiber 3. The optical path shown in FIG. 1 shows a path of light that is input from the light emitting element 1 to the optical fiber through the obliquely polished rod lens 2.

Since the rod lens is cylindrical in FIG. 1, the reflected light M is dispersed and is not input to the light emitting element even if the output optical axis of the light emitting element 1 and the rod lens 2 make a right angle. After the fiber 3 and the light emitting element 1 are pre-positioned, the oblique polishing rod lens 2 may be positioned so that the light output from the light emitting element 1 is condensed in the optical fiber.

As described above, in FIG. 1, since the obliquely polished surface of the obliquely polished rod lens 2 reflects the light output from the light emitting element 1 and collects it in the optical fiber, the accuracy of the prism assembly position shifts. Stable light output without
Furthermore, since the optical fiber 3 and the light emitting element 1 are pre-positioned and then the slanted polishing rod lens 2 is positioned, an optical transmitter module having a good assembling property can be obtained.

Example 2. FIG. 2 is a block diagram showing an optical receiving module according to the present invention. In the figure, 4 is a light receiving element, 2 is an obliquely polished rod lens, and 3 is an optical fiber.

Next, the operation will be described. Optical fiber 3
The light output from is input to the oblique polishing rod lens 2. The light input to the oblique polishing rod lens 2 is reflected by the oblique polishing end of the oblique polishing rod lens 2 and output from the side surface of the oblique polishing rod lens 2. The light passing through the obliquely polished rod lens 2 is condensed and input to the light receiving element 4. The optical path shown in FIG. 2 shows the path of light that is input from the optical fiber 3 to the light receiving element 4 via the obliquely polished rod lens 2.

Further, in FIG. 2, since the obliquely polished rod lens 2 has a cylindrical shape, even if the angle between the optical axis of the light input to the light receiving element 4 and the obliquely polished rod lens 2 is a right angle, the surface of the light receiving element 4 is Since the reflected light M of the light is dispersed on the side surface of the oblique polishing rod lens 2 and is not input to the optical fiber 3, the light output from the optical fiber 3 from the oblique polishing rod lens 2 after the optical fiber 3 and the light receiving element 4 are pre-positioned. It may be positioned so that the output is condensed in the light receiving element 4.

As described above, since the obliquely polished rod lens 2 in FIG. 2 reflects the light output from the optical fiber 3 and focuses it on the light receiving element, the prism assembly position accuracy does not shift and stable light receiving characteristics are obtained. Optical fiber 3 obtained
Since it is only necessary to position the light-receiving element 4 in advance and then position the obliquely polished rod lens 2, an optical receiving module with good assemblability can be obtained.

[0020]

As described above, according to the present invention, since the rod lens also functions as a prism, stable operation characteristics can be obtained without deviation of the assembly position accuracy of the prism, and the assembling property is good. It has the effect of being cheaply assembled.

[Brief description of drawings]

FIG. 1 is a diagram showing an optical transmission module according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an optical receiver module according to a second embodiment of the invention.

FIG. 3 is a diagram showing a conventional optical transmission module.

[Explanation of symbols]

 1 light emitting element 2 obliquely polished rod lens 3 optical fiber 4 light receiving element 5 prism 6 optical element

Claims (2)

[Claims] 1. A light emitting element, an obliquely polished rod lens into which light emitted from the light emitting element is input from a side surface, and the incident light is reflected by a surface having one end obliquely polished and emitted from the other end, and the obliquely polished rod lens. An optical module, comprising: an optical fiber to which the output light from the polishing rod lens is input. 2. An optical fiber into which light is input and a light output from this optical fiber are incident, and the incident light is reflected by a surface whose one end is obliquely polished and emitted from its side surface. An optical module comprising: a light receiving element on which the output light of the obliquely polished rod lens is incident.