JPS61264778A - Semiconductor light-emitting device - Google Patents

Abstract

PURPOSE:To provide a compact and inexpensive semiconductor light-emitting device which can couple light emitted from an LD chip with a light-receiving element and which has a high reliability, by providing an opening in a stem for taking out light emitted from the LD chip and disposing a spherical lens in this opening. CONSTITUTION:A cap, which is provided with a window for taking out light emitted from the upper end face of an LD chip 12 so as to use the light for a signal, is attached to a stem 11. The stem 11 is provided with an opening for taking out emitted light so as to use the light for control, and a spherical lens 15 is fixed in the opening with a brazing material in a hermetically sealed manner. The spherical lens 15 is fixed at a predetermined distance from the end face of the LD chip, and the distance is previously calculated such that the lens can focus the light on and couple the light to a light-emitting element 14. Thus, since the section for mounting the LD chip 12 and the opening for taking out emitted light for control are provided integrally in the stem 11 with a high precision, the LD chip 12 as well as the spherical lens 15 can be positioned accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a semiconductor light emitting device, and particularly to the structure of a package in which a semiconductor laser is mounted.

(Prior Art) A semiconductor laser device (hereinafter referred to as an LD chip) used for optical communication emits laser light from both end faces.
The light emitted from one of the two end faces is used for signal transmission, and the light emitted from the other end face is used to sense output fluctuations in the output light due to effects such as temperature changes, and increase or decrease this output fluctuation. It is used for control purposes to keep the output of emitted light constant. In this case, a light receiving element such as a PIN photodiode is generally used to receive the emitted light for control purposes.

The configuration will be explained below using figures.

FIG. 3 is a sectional view of a conventional semiconductor light emitting device.

In this figure, 1 is a stem that also serves as a heat sink, 2
is an LD chip, 3 is a cap having a window for taking out the light emitted from the LD chip 2, 4 is a light receiving element, 5 is a thin optical glass for airtight sealing, 6 is a condensing lens, 7 is transparent glass,
8 is brazing material. As shown in this figure, the LD chip 2 is attached to the tip of the stem 1 and arranged so that the signal light output is emitted upward and the control light output is emitted downward. On the signal output light side, a cap having a transparent glass 7 through which light passes is welded and fixed to the stem 1 in an airtight manner. On the other hand, a hole is provided in the stem l at a position where the control output light is emitted, and a thin plate-shaped glass 5 through which the light passes is fixed with a brazing material 8 so as to be hermetically sealed. . Incidentally, in order to efficiently couple the signal output light to an optical fiber or the like, various coupling methods are usually adopted depending on the purpose, performance, and cost.

For example, in the case of coupling with a single mode optical fiber, high coupling is required, so an optical lens system that combines a ball lens and a gradient index lens is used, and in the case of coupling with a multimode optical fiber, a ball lens or a gradient index lens is used. I am trying to use .

However, on the control side, highly efficient coupling is not required because it is sufficient to extract a certain amount of output light for control signals. Usually, as shown in FIG. 3 above, the gradient index lens 8 is placed outside the semiconductor light emitting device and coupled to the light receiving element 4.

(Problems to be Solved by the Invention) However, in the device having the above configuration, the gradient index lens 6 for coupling the control output light to the light receiving element 4 is
, and also requires a member to fix it,
There are problems in that the number of parts and assembly man-hours increase, increasing costs, and the increase in the number of parts hinders miniaturization. Furthermore, there is a problem in that alignment of the optical axes becomes difficult because the number of parts for optical coupling increases.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned problems and provide a semiconductor light emitting device that can easily couple the light emitted from an LD chip to a light receiving element, is compact, inexpensive, and has high reliability.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a stem to which the LD chip is attached with an exit light exit port from the LD chip, and a ball lens in the exit light exit port. place,
The ball lens is hermetically sealed and fixed with brazing material.

(Function) As shown in FIG. 1, the emitted light from the LD chip 12 passes through the ball lens 15 which is hermetically sealed and fixed to the emitted light outlet provided in the stem 11 to the light receiving element 1.
Combined with 4. In this case, the ball lens 15 functions as an optical coupler, and optical coupling between the LD chip 12 and the light receiving element 14 can be easily and compactly performed.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a semiconductor light emitting device according to the present invention,
FIG. 2 is an external perspective view of the semiconductor light emitting device.

First, the structure of this device will be explained.

In FIGS. 1 and 2, 11 is a stem for attaching an LD chip, and also serves as a heat sink. Reference numeral 12 denotes an LD chip attached to the tip of the stem 11, and outputs light in the vertical direction from both end surfaces of the LD chip 12.

13 is a cap provided with a window for taking out the light emitted from the LD chip 12 at the top; 14 is a light receiving element; for example,
These include PIN photodiodes and avalanche photodiodes. 15 is a ball lens, and 16 is a brazing material for fixing the ball lens 15 and performing airtight sealing.

As shown in these figures, the LD chip 12 is attached to the distal end of the stem 11 with both end surfaces facing up and down. A cap is attached to the stem 11 by welding, and the cap is provided with an emitted light extraction window for extracting the emitted light from the upper end surface of the LD chip 12 to the outside for use as a signal. On the other hand, the stem 11 is provided with a control output light extraction port, and a ball lens 15 is fixed to the extraction port with a solder material 16 for hermetically sealing. The distance from the end face of the LD chip 12 is calculated in advance, and the ball lens 15 is fixed at a predetermined position so that the light is focused and coupled to the light receiving element 14 at a certain distance. In this embodiment, the mounting part of the LD chip 12 and the control light output outlet are integrally formed on the stem 11 with high precision, so the positioning of the LD chip 12 and the ball lens 15 can be accurately performed. It can be carried out. In addition, the control light output outlet is provided with a taper to accurately determine the vertical position of the ball lens 15, and the LD chip 12, the ball lens, and 15 are designed with high precision to monitor the output light. Positioning and fixing can be performed using a positioning solder device.

Furthermore, the present invention is not limited to the above embodiments,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described above in detail, the present invention includes a semiconductor laser chip that outputs emitted light from both end faces, a stem to which the semiconductor laser chip is attached, and a cap fixed to the stem. In the semiconductor light emitting device, the stem is provided with an opening for attaching light emitted from the semiconductor laser chip, a ball lens is disposed in the outlet, the ball lens is fixed with a brazing material, and hermetically sealed. (1) The light emitted from the LD chip can be easily combined with the control light receiving element, etc., and the number of parts and assembly man-hours can be reduced, leading to cost reduction.

(2) The number of parts can be reduced, the space required can be reduced, and compactness can be achieved.

(3) Connection loss of emitted light can be reduced and stable optical coupling can be performed.

As described above, the present invention has various advantages, and the effects brought about by it are remarkable.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a semiconductor light emitting device according to the present invention, FIG. 2 is an external perspective view of the semiconductor light emitting device, and FIG. 3 is a sectional view of a conventional semiconductor light emitting device. 11... Stem, 12... LD chip, 13...
Cap, 14... Light receiving element, 15... Ball lens,
16... wax wood.

Claims (2)

[Claims] (1) In a semiconductor light emitting device having a semiconductor laser chip that outputs emitted light from both end faces, a stem to which the semiconductor laser chip is attached, and a cap fixed to the stem, the stem includes a What is claimed is: 1. A semiconductor light-emitting device comprising: an exit port for emitted light, a ball lens disposed in the exit port, the ball lens fixed with a brazing material and hermetically sealed. (2) The semiconductor light emitting device according to claim 1, wherein the output light from the ball lens is guided to a light receiving element for obtaining a control signal.