JPS61279190A - Semiconductor light emitting device with optical fiber - Google Patents

Abstract

PURPOSE:To provide stable coupling with respect to succeeding temperature change, by applying an external force to a part of the bottom of a package, forming an attaching part having the shape of a deformable post, and attaching the tip of a piece of optical fiber to the attaching part so as to face the emitting surface of a light emitting element. CONSTITUTION:A laser diode 2 is fixed on a secondary mount 2 through a bonding material. The secondary mount 2 is fixed on an attaching part 3a at the bottom part of a package 3 through a bonding material. Meanwhile, an optical fiber 4 is positioned at a fiber guide 5 so as to face a light emitting surface in such a way that the emitted light from the diode 1 can be efficiently converged. In order to align the diode 1 and the optical coupling end of the optical fiber 4, the optical fiber 4 is firmly fixed, and the attaching part 3a is deformed and adjusted so that the maximum optical coupling efficiency is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a semiconductor light emitting device with an optical fiber, and particularly to a semiconductor light emitting device with an optical fiber suitable for application to optical communications.

[Background of the invention]

2. Description of the Related Art A semiconductor light-emitting device with an optical fiber used for optical communication or the like is arranged in a package so that an output surface of a semiconductor light-emitting element such as a laser diode and an optical coupling end, which is the tip of an optical fiber, face each other. The optical coupling end of the optical fiber is processed into a photosphere lens in advance in order to efficiently introduce light from the semiconductor light emitting device. When optically coupled with this structure, the optical coupling efficiency changes due to the relative positional shift between the semiconductor light emitting element and the optical coupling end of the optical fiber.

Now, for example, a laser diode is used as a semiconductor element, a single mode fiber with a core diameter of 5 to 10 μφ is used as an optical fiber, and the optical axis direction is determined as a change in the relative position between the laser diode and the optical coupling end of the optical fiber. 2
If the direction perpendicular to the optical axis direction is the Y direction and the horizontal direction is the become. As can be seen from Figures 5 and 6, the optical coupling efficiency has a relatively large tolerance range for the amount of positional deviation in the Z direction, but for the amount of positional deviation in the Y direction (the same applies to the The tolerance range is small, and the efficiency decreases by about 15% for a positional deviation amount of ±1 μm. This result shows that a single mode fiber (core diameter 5 to 10 μmφ) is used as an optical fiber.
), and the above tolerance range becomes somewhat larger for multimode fibers (core diameter 45 to 62 μmφ). Therefore, in order to obtain high optical coupling efficiency,
When assembling or using a laser diode and an optical fiber, it is important to have a structure that does not cause misalignment between the laser diode and the tip of the optical fiber.

Therefore, in the conventional structure, as described in Japanese Unexamined Patent Publication No. 60-43889, the laser diode is bonded and fixed to the center of the package via a submount, and the tip side of the fiber is It has a structure in which it is joined and fixed via a support member. Therefore, external forces applied to the package will not cause relative positional deviation between the laser diode and the optical fiber, and in the event that positional deviation occurs, the optical coupling efficiency can be improved by deforming the support member on the fiber tip side. The structure is designed to recover.

However, in such a conventional structure, if the package is left in high temperature for a long time, the linear expansion coefficients of the fiber, stem, etc. are different, so thermal strain occurs in the support part on the fiber tip side, and the fiber fixing member is damaged. No consideration was given to deformation or breakage, which would cause a relative positional shift between the laser diode and the optical fiber.

[Purpose of the invention]

An object of the present invention is to provide a semiconductor light emitting device with an optical fiber that can always provide stable optical coupling efficiency even when the package is left in a high temperature atmosphere for a long time or at room temperature for a long time.

[Summary of the invention]

A feature of the present invention is that an external force is applied to a part of the bottom of the package to which the submount and the semiconductor light emitting element are attached to form a deformable post-shaped attachment part, and the tip of the optical fiber is attached to this attachment part to emit light from the semiconductor light emitting element. By mounting it so that it faces the surface, the semiconductor light emitting element and the optical coupling end of the tip of the optical fiber can be aligned to the optimum position while adjusting the post-shaped light emitting element mounting part. .

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

The laser diode 1 is fixed to a submount 2-L made of a material such as SiC via a bonding material such as solder. This submount 2 is a post-shaped mounting portion 3a at the bottom of a package 3 made of a material such as Kovar.
1 through a bonding material such as solder. On the other hand, the optical fiber 4 is positioned so as to face the output surface so that the light emitted from the laser diode 1 can be efficiently focused on the fiber guide 5 attached to the package 3, and the optical fiber 4 is located at the tip portion 4a and the intermediate portion 4b. Fixed with solder or adhesive. This fiber guide 5 is fixed to a tubular jacket guide 8 with a bonding material such as silver solder.

Further, this jacket guide 8 is fixed to the side surface of the package 3 with a bonding material such as silver solder. In addition,
This optical fiber 4 includes a core portion having a high refractive index such as quartz glass material, a cladding portion that covers this core portion and has a lower refractive index than the core portion, and a cladding portion such as nylon or the like that covers the surface to protect the core portion. The light incident on the core is confined due to the difference in refractive index, and is transmitted through repeated total reflections within the core.

A light receiving element 6 is provided to monitor the light emitted from the laser diode 1 and to always obtain a constant light output. A cap 7 prevents moisture from entering the package 3 and maintains airtightness.

In such a configuration, in order to align the laser diode 1 and the optical coupling end of the optical fiber 4, first,
The optical fiber 4 is fixed securely, and then adjustment is made by deforming the post-shaped attachment portion 3a of the package 3 so that the optical coupling efficiency is maximized. With this configuration, even if the package 3 is left at a high temperature for a long time, the optical coupling end of the optical fiber 4 will not protrude or shift its position because the optical fiber 4 is fixed by the fiber guide 5. On the other hand, if the attachment portion 3a of the package 3 is deformed for adjustment, an elastic aftereffect may occur and the attachment portion 3a may return to its original state within a short period of time. For example, attaching the post-shaped mounting portion 3d as shown in Fig. 2 to ■7.
The amount of recovery ■4□ due to the elastic aftereffect after deformation is the seventh
This is shown in Figure 3. In Fig. 3, the horizontal axis represents time, and the vertical axis represents return welfare ■4□. In addition, the width of each point in the figure indicates the width of the initial deformation. As can be seen from this figure, regardless of the size of the initial deformation r,
(2) and 2 become constant values within a relatively short time and remain stable thereafter without deformation. Therefore, it can be seen that the position of the laser diode 1 and the optical fiber 4 becomes stable when the position of the laser diode 1 is adjusted, left in that state for a short time, and then aligned again.

The above-mentioned post-shaped mounting portion 3a may have a cutout groove at its base, and may also have a prismatic or inverted conical shape in addition to a cylindrical shape. Furthermore, a structure may be considered in which position adjustment between the laser diode 1 and the light receiving element 6 is eliminated by arranging the laser diode 1 and the light receiving element 6 in the same mounting part.

The shape of the mounting portion 3a may be a slate shape such as a cylinder or a complicated shape, for example, as shown in FIG. 4.

This r-shape allows alignment in the lateral direction (X direction) and alignment in the vertical direction (Y direction) to be performed separately, which has the effect of allowing more accurate alignment.

〔Effect of the invention〕

According to the present invention, by aligning the laser diode and the optical fiber by deforming the laser diode part, it is possible to obtain a semiconductor light-emitting device with an optical fiber that has stable optical coupling against subsequent temperature changes. .

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of an embodiment of a half to three optical device with optical fibers, FIG. 2 is a diagram showing a light emitting element mounting part in FIG. 1,
FIG. 3 is a diagram illustrating the elastic surface aftereffect of the mounting portion shown in FIG. FIG. 6 is a diagram showing the amount of displacement in the Y direction and the optical coupling efficiency between the laser diode and the optical fiber. 1...Laser diode, 2...Submount, 3
... Package, 3a... Mounting part, 4... Optical fiber, 5... Fiber guide, 6... Light receiving element, 7
...Character 1st map 2nd map gun (V,) + a dimension to X (phantom Qin Q + wise V

Claims (1)

[Claims] 1. A semiconductor light emitting device with an optical fiber, which includes a light emitting element bonded to the bottom of a package via a submount, and an optical fiber fixed so that emitted light can be introduced into the vicinity of the light emitting element. The device is characterized in that the light emitting element and the submount are bonded and fixed to an easily deformable mounting part on the bottom of the package, and by deforming this mounting part, the direction of light emitted from the end face of the light emitting element can be adjusted. If so, it is a semiconductor light emitting device with optical fiber. 2. The shape of the light emitting element mounting part on the bottom of the package is prismatic.
The semiconductor light emitting device with an optical fiber according to claim 1, characterized in that the semiconductor light emitting device has a cylinder, an inverted cone, or an inverted L shape.