JPS6057694A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To prevent the resonator, etc., of the titled laser from being deteriorated and to stabilize operation of the laser by a method wherein, when outgoing light emitted from a laser element is made to reflect by a window on the face of a cap to be used for sealing the outgoing light airtightly, the face of the cap is inclinedly constituted to an extent that the reflected light at the end face of the window doesn't return to the laser element. CONSTITUTION:A semiconductor element 1 is mounted on the laser submount 10 of a semiconductor laser and outgoing light 6 emitted from the laser element 1 is reflected by the light-outgoing window 2 of a cap to be used for sealing the outgoing light airtightly. The light-outgoing window 2 is inclinedly constituted to an extent that the reflected light 7 reflected by the light-outgoing window 2 of the cap 3 doesn't return to the active layer of the lase element 1. According to this constitution, the reflected light at both ends of the light-outgoing window 2 is prevented from intruding into the active layer of the laser element 1 and stabilization of the semiconductor laser is contrived. When a magnetooptic crystal 12 is used for an isolator for light source for optical communication, wherein this semiconductor laser has been used, deterioration of the resonator, etc., is prevented and operation of the laser is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a semiconductor laser device used as a light source for optical communications, optical information processing, optical sensors, and the like.

Conventional Structure and Problems When converting a semiconductor laser into a device, as shown in FIG. 1, a layer of sapphire glass, etc. A structure is used in which hermetic sealing is performed by a cap 3 having a structure in which a window 2 is disposed, and an electrode 4.5 is taken out by a hermetic seal.

FIG. 2 shows the groove ends of the semiconductor laser stack. The light 6 emitted from the resonator end face 8 on one side of the semiconductor laser is parallel to the resonator end face 8 of the semiconductor laser element 1 within the light exit plane of the hermetic sealing cap 3 of the semiconductor laser element 1 shown in FIG. A portion of the light is reflected by both end faces of the light emitting window 2, which is configured as follows, and returns to the active layer 9 of the semiconductor laser device 1. 10 is a laser submount. It has been pointed out that when reflected light from emitted light returns to the active layer of a semiconductor laser, this causes instability of the oscillation characteristics of the semiconductor laser and an increase in noise. That is, in order to use a semiconductor laser as a light source for optical communication or optical information processing, it is necessary to remove as much return light as possible.

OBJECTS OF THE INVENTION It is an object of the invention to prevent light reflected from the window of the soil cap from returning to the active layer of the semiconductor laser and to obtain a stable light source.

Structure of the Invention The structure of the present invention uses a semiconductor laser device and a cap for hermetically sealing the semiconductor laser device whose emission surface is inclined with respect to the resonator surface of the semiconductor laser device to prevent reflected light from returning to the active layer. It is something to prevent.

DESCRIPTION OF EMBODIMENTS The structure of the first embodiment of the semiconductor laser device of the present invention will be explained in the third
As shown in the figure. In FIG. 3, the emitted light 6 from the semiconductor laser element is reflected by the light emitting window 2 of the hermetic sealing cap 3 on the light emitting surface of the hermetic sealing cap 3, and the reflected light 7 is transmitted to the semiconductor laser element 1. By configuring it so that it does not return to the active layer 9 of the semiconductor laser 1, reflections at both ends of the light exit window 2 can be prevented from entering the active layer 9 of the semiconductor laser 1, and the half-z, q-body laser can be stabilized. .

In a second embodiment, a magneto-optic crystal 12 was used as the material for the light exit window 2 of the semiconductor laser device of the present invention, as shown in FIG. When a semiconductor laser device using a magneto-optic crystal is used as a light source for optical communication or optical information processing, etc.,
The product can be configured to add the function of an optical isolator. When a semiconductor laser device is used as a light source for optical communication, it is placed in the middle of an optical circuit (for example, at the end of an optical fiber connector), and when it is used as a light source for optical information processing, it is placed on an optical disk, for example. If reflected light from a surface returns to the semiconductor laser, which is the light source, it becomes noise and the oscillation of the semiconductor laser becomes unstable. Therefore, the light emitted from the semiconductor laser should be passed through, or the light returning to the semiconductor laser, which would cause noise, should be blocked. It is something that does work.

FIG. 4 shows a configuration diagram of a light source using the second embodiment as a light source for optical fiber communication and adding the function of an optical isolator. 13 is a magnet, and 14 is an analyzer, which are arranged at a position of 45° with respect to the polarization direction of the light emitted from the semiconductor laser element. 11 is an optical element having a beam conversion function, and 15 is an optical fiber.

The optical element 11 having a beam conversion function referred to here is:
It has some kind of beam conversion function, such as a spherical lens, gradient index lens, hemispherical lens, or cylinder lens. Emitted light with the same polarization direction from the semiconductor laser element 1 is made into parallel light by an optical element 11 having a beam conversion function, and passes through a light exit window made of a thick magneto-optic crystal 12 that rotates the polarization direction by 450 degrees. do. At this time, the reflected light from both end faces of the light exit window does not return to the active layer 9 of the semiconductor laser element.

When the magneto-optic crystal is placed parallel to the light emitting surface of the semiconductor laser element, the reflection from the end face of the magneto-optic crystal on the semiconductor laser element side was 14% when no anti-reflection film was applied, but with the present invention, , it became less than 0.5%.

Note that the optical element 11 having a beam conversion function may be integrated into the window material 2.

To describe the operation of the apparatus shown in FIG. 4, the polarization direction of the parallel light emitted from the semiconductor laser 1 is rotated by 45 degrees by passing through the magneto-optic crystal 12 magnetized by the magnet 13, and the light passes through the analyzer 14. The light is collected by 11 optical elements and sent to an optical fiber 15. On the other hand, the light that has passed through the analyzer 14 and has the same polarization direction and is in the opposite direction to the output direction has its polarization plane further rotated by 45 degrees when passing through the magneto-optic crystal 12 due to the non-reciprocity of the magneto-optic crystal 12. However, when it passes through the optical element 11 and returns to the active layer of the semiconductor laser 1,
The polarization direction is perpendicular to the polarization direction of the light emitted from the semiconductor laser. Therefore, light with a polarization direction perpendicular to the polarization direction of the output light of the semiconductor laser does not become noise in the semiconductor laser and does not cause instability of the oscillation characteristics, so the semiconductor laser can be stabilized. .

Effects of the Invention By using the semiconductor laser device of the present invention, the reflected light from the light emitting surface of the hermetic sealing cap, which is necessary to prevent deterioration of the resonator surface, etc. and ensure reliability, is reflected from the semiconductor laser. It is possible to realize a semiconductor laser device that is reliable, has stable oscillation characteristics, and has low noise.

Furthermore, by selecting the window material for the hermetic sealing cap, the construction of the isolator etc. is easy and reliable.
Moreover, a semiconductor laser device with stable oscillation characteristics and low noise can be realized.

[Brief explanation of drawings]

Fig. 1 is an external view and internal configuration diagram of a semiconductor laser device sealed with a conventional hermetic sealing cap, Fig. 2 is an enlarged view of main parts of a semiconductor laser element, and Fig. 3 is a semiconductor laser device according to an embodiment of the present invention. FIG. 4 is a diagram showing the internal configuration of an isolator for a light source for optical communication using the semiconductor laser device of the present invention. 1...-semiconductor laser element, 6...-emitted light, 7-
...Reflected light from both ends of the light exit window, 8.. Cavity end face on one side of the semiconductor laser, 9.. Active layer, 12.
...Magneto-optical crystal, 13--Magnet. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 2 Figure 4

Claims (2)

[Claims] (1) Light is emitted from the airtight sealing gap to the extent that reflected light from the end face of the window on the light exit surface of the airtight sealing cap for light emitted from the semiconductor laser bare hand does not return to the active layer of the semiconductor laser element. A semiconductor laser device characterized by an inclined surface. (2) A semiconductor laser device according to claim 1, characterized in that a magneto-optic crystal is used as a window material of a cap for hermetically sealing a semiconductor laser element.