JPH01291206A - Optical semiconductor module - Google Patents

Abstract

PURPOSE:To reduce the number of parts to reduce cost and to improve reliability by mounting a fiber assembly to an optical semiconductor assembly constituted of optical semiconductor elements and a piece of lens in such a manner that the fiber assembly can rotate around the axis inclined by a prescribed angle from the exit light axis thereof. CONSTITUTION:The fiber assembly 6 is formed by integrating the optical fibers 4 and the lens 5 by the optical semiconductor module formed to optical couple the light emitted from a optical semiconductor element 1 to the optical fibers 4 by 2 pieces of the lenses. This fiber assembly 6 is mounted to the optical semiconductor assembly 3 constituted of the optical semiconductor elements 1 and a piece of the lens 2 in such a manner that the fiber assembly can rotate around the axis z' inclined by the prescribed angle alpha from the exist light axis (z) of the optical semiconductor assembly, by which the selection of the optimum angle of the incident ray with the (z) axis within the range from -theta' up to +theta is enabled and the optimum optical coupling is attained. The reduced cost is thereby obtd. from the reduced number of parts and the improved reliability is attained from the decreased joint surfaces.

Description

[Detailed Description of the Invention] Overview An optical semiconductor module is provided that is formed by optically coupling an optical semiconductor element and an optical fiber, and that reduces the number of parts, lowers the cost, and improves reliability. In an optical semiconductor module in which light emitted from an optical semiconductor element is optically coupled to an optical fiber by two or more lenses, the optical fiber and at least one lens are integrated. to form a fiber assembly, and the fiber assembly is rotatably taken around an axis tilted at a predetermined angle with respect to the output optical axis of the optical semiconductor assembly, which is composed of at least an optical semiconductor element and one lens. Configure.

INDUSTRIAL APPLICATION FIELD The present invention relates to an optical semiconductor module comprising an optical semiconductor element and an optical fiber optically coupled.

For example, in an optical communication system that uses an optical fiber as an optical transmission path, an optical semiconductor element and an optical An optical semiconductor module is used in which a fiber input end face is fixed in a predetermined positional relationship and a condensing lens is provided between them.

In this type of optical semiconductor module, the positional relationship between the component parts directly affects the optical coupling efficiency, so each component is required to be positioned with extremely high precision of 1 μm or less. Furthermore, it is required that this positioning accuracy be maintained for a long period of time. In particular, semiconductor laser modules used for long-distance, high-speed communications require high output and a single wavelength, and therefore require characteristics such as high optical coupling efficiency and small amount of reflected feedback.

BACKGROUND OF THE INVENTION FIG. 3 shows a cross-sectional view of a conventional optical semiconductor module. 11 is an optical semiconductor element such as an LD (semiconductor laser), and 12 is a lens such as a ball lens. The relative positional relationship between the optical semiconductor element 11 and the first lens 12 is adjusted, and both are fixed in the best positional relationship. The adjustment of the positional relationship referred to here includes focus adjustment to adjust the separation distance between the optical semiconductor element 11 and the second lens 12 so that the light beam shape of the collimated light emitted from the second lens 12 is within a permissible range, and This can be divided into alignment adjustment, in which the first lens 12 is adjusted in a direction perpendicular to the optical axis with respect to the optical semiconductor element 11 so that the emission direction of the light is within a permissible range. In this way, the focus and alignment of the optical semiconductor element 11 and the first lens 12 are adjusted at the assembly stage.

13 is a terminal board, and a cap 14 made of Kovar or the like is resistance welded to this terminal board to package the optical semiconductor element 11 and the first lens 12. The cap 14 is provided with a glass window 15 for emitting a light beam. 16 is a terminal for supplying a drive current to the optical semiconductor element 11. A support member 17 is fixed on the terminal board 13, and an optical isolator 1 is mounted on this support member 17.
8 is installed. Optical semiconductor assembly 20 includes optical semiconductor element 11, lens 12, and optical isolator 18.
Configure.

21 is a second lens for adjusting the optical axis. A support member 22 is fixed on the optical isolator 18, and a cylindrical holder 23 is mounted on the support member 22.

Reference numeral 24 denotes an optical fiber, and one end face 24a of the optical fiber is obliquely polished together with a ferrule 25 to prevent reflected light from returning at the end face. 26 is an optical fiber end face 24a
It is a 2-2 lens for focusing a light beam on the cylindrical sleeve 27 and is inserted together with the ferrule 25 to form a fiber assembly 28. The reason why components such as the optical semiconductor assembly 20 and the fiber assembly 28 are assembled is that the optical axis of the entire module can be easily adjusted by adjusting the positional relationship of the assemblies.

To assemble the optical semiconductor module, the optical semiconductor assembly 20, the fiber assembly 28 and the second lens 21 are assembled.
It is assembled by adjusting the optical axis and fixing. This is because the optical fiber end face 24a is polished obliquely, so the optimal light beam entering the fiber assembly 28 is not parallel to the optical axis of the module, and the angle of the output light beam from the semiconductor assembly 20 also varies. This is because it is necessary to adjust the light beam incident on the optical fiber end face 24H at the second lens 21 so that it has an optimal angle.

Problems to be Solved by the Invention In the conventional optical semiconductor module as described above, a second lens is provided in order to obtain a light beam at an optimal angle to be incident on the obliquely polished end face of the optical fiber. There is a problem that the number of parts of the optical semiconductor module is large, and the price of the module is high.

The present invention has been made in view of these points, and its purpose is to provide an optical semiconductor module that reduces the number of parts, lowers the cost, and improves reliability.

A means to solve problems FIG. 1 is a diagram showing the principle of the present invention.

In the optical semiconductor module in which the light emitted from the optical semiconductor element X is optically coupled to the optical fiber 4 by two or more lenses, the optical fiber 4 and at least one
A fiber assembly 6 is formed by integrating the lenses 5. This fiber assembly 6 is attached to an axis 2 which is inclined at a predetermined angle α with respect to an output optical axis Z of an optical semiconductor assembly 3 which is composed of at least an optical semiconductor element 1 and one lens 2.
’ to be rotatably attached.

In this way, when the axis 2'' of the fiber assembly 6 is installed at a predetermined angle α with respect to the output optical axis 2 of the optical semiconductor assembly 3, the optimum incident light beam can be adjusted by rotating the fiber assembly 6 around the Z' axis. The angle with respect to the Z axis can be selected within the range of −0° to 10θ.

Therefore, the output light from the optical semiconductor assembly 3 is 10~
If it is between 10 and 10, it is possible to obtain optimal optical coupling with an optical system in which the second lens is removed.

Embodiments The present invention will be explained in detail below based on embodiments shown in the drawings. In the description of this embodiment, the same components as those of the conventional example shown in FIG. 3 are denoted by the same reference numerals, and the description thereof will be partially omitted.

FIG. 2 is a sectional view of an embodiment of the present invention. An optical semiconductor element 11 such as an LD and a lens 12 such as a ball lens are fixed together after focus adjustment and alignment adjustment, and are sealed in a cap 14 and packaged. A support member 17 is fixed on the terminal board 13, and an optical isolator 1 is provided on the support member 17 to prevent reflected feedback light from passing through.
8 is provided. Optical semiconductor element 11, first lens 12
The optical isolator 18 is then adjusted for focus and alignment and assembled integrally as an optical semiconductor assembly 'J20. In this way, by adjusting the focus and alignment at the assembly stage, it becomes easier to adjust the optical axis of the entire module by adjusting the alignment between the assemblies, and it is possible to achieve optical coupling efficiency above a predetermined value. It has become.

A cylindrical holder 30 is mounted on the optical isolator 18 so as to be inclined at a predetermined angle α. 24 is an optical fiber, and the end face 24a of the optical fiber is obliquely polished together with a ferrule 25, and this ferrule 25 is connected to the second-second lens 2.
After the fiber assembly 25 and the second lens 26 are inserted into the cylindrical sleeve 27 and the focus is adjusted, the ferrule 25 and the second-second lens 26 are fixed in the cylindrical sleeve 27 to obtain a fiber assembly 28.

The reason why the optical fiber end face 24a is polished obliquely is to prevent reflected feedback light from the optical fiber end face 24a. Therefore, the optimal incident light beam that enters the optical fiber end face 24a is not parallel to the optical axis Z of the optical semiconductor assembly 20, but is a light beam that is at a predetermined angle with respect to the optical axis 2. Therefore, in this embodiment, the cylindrical holder 30 is attached at a predetermined angle α with respect to the optical axis 2 of the optical semiconductor assembly 20, and the fiber assembly 28 is fitted into the cylindrical holder 30.

For example, the inclination angle of the optical fiber end surface 24H is 6°, the FM between the optical fiber 24 and the second-second lens 26 is 50 μm,
Assuming that the pitch of the second-second lens 26 is 0°16 and its focal length is 2.3 mm, the optimum angle of light incident on the fiber assembly 28 is approximately 1.4° with respect to the optical axis Z' of the fiber assembly 28. Become. Therefore, by setting the inclination angle α of the cylindrical holder 30 to 1.4°, by rotating the fiber assembly 28 within the holder 30, the optimum incident angle can be adjusted to the range of θ to 2.8° with respect to the Z axis. can be selected arbitrarily.

Therefore, even if the output angle of the output light from the optical semiconductor assembly IJ 20 varies within the range of 0° to 2.8°, it can be corrected by rotating the fiber assembly 28 within the cylindrical holder 30, which is not necessary in the past. It is possible to realize an optical system that does not use the conventional second lens.

Effects of the Invention Since the optical semiconductor module of the present invention is configured as detailed above, it is possible to reduce the cost by reducing the number of parts.
Furthermore, since the number of bonding surfaces is reduced, a highly reliable optical semiconductor module can be provided.

[Brief explanation of the drawing]

Figure 1 is a diagram of the principle of the present invention. FIG. 2 is a sectional view of an embodiment of the present invention; FIG. 3 is a sectional view of a conventional optical semiconductor module. 1.11... Optical semiconductor element, 2.12... Runs, 3.20... Optical semiconductor assembly, 4.24...Optical fiber, 5.26...2nd-2nd lens, 6.28...Fiber assembly, 18... Optical isolator 1 ．． 30...Cylindrical holder.

Claims (1)

[Scope of Claims] An optical semiconductor module in which light emitted from an optical semiconductor element (1) is optically coupled to an optical fiber (4) using two or more lenses, comprising: and at least one lens (5)
are integrated to form a fiber assembly (6), and the fiber assembly (6) is integrated with at least an optical semiconductor element (
1) and one lens (2). Features of optical semiconductor module.