JPS61127189A - Optical semiconductor device - Google Patents

Abstract

PURPOSE:To reduce the effect of the return light from the infrared-transmitting plate and to prevent a reflected wave noise from generating in an optical semiconductor device by a method wherein an optical semiconductor element is disposed in the cooling container having a window consisting of the infrared- transmitting plate and the other infrared-transmitting plate slanted to the optical axis of the optical semiconductor device is arranged between the optical semiconductor element and the infrared-transmitting plate. CONSTITUTION:The optical semiconductor device is constituted of a cooling container 1 consisting of a Dewar vessel, a window 2 consisting of an infrared- transmitting plate, a cooling substrate 3, a heat sink 4 consisting of copper, a ceramic layer 5, a laser chip 6, a ribbon line 7, a cover 8 and an infrared- transmitting plate 11, which is mounted slantingly to the optical axis of the device in the front of the cover 8. A return light 10 from the infrared- transmitting plate 2 is reflected by the infrared-transmitting plate 11 and does not make incident to the laser chip 6. Accordingly, the generation of a reflected wave noise can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an optical semiconductor device equipped with an optical semiconductor element that needs to be cooled when used, such as an optical semiconductor device suitable for use in the field of infrared light. Related to optical semiconductor devices.

[Conventional technology]

For example, a lead salt laser that generates infrared light must be operated while being cooled, so it is
ssel).

FIG. 2 is a cross-sectional side view of essential parts of a conventional optical semiconductor device of this type.

In the figure, 1 is a deair bottle, which is a cold container, and 2 is a container for barium fluoride, germanium (Ge), or silicon (S).
3 is a cooling base, 4 is a heat sink made of, for example, copper (Cu), 5 is a ceramic layer, 6 is a laser chip, and 7 is a ribbon made of, for example, gold (Au). 8 represents the cover, 9 represents the emitted infrared light, and 10 represents the returned light.

As can be seen from the figure, in this optical semiconductor device, a part of the infrared light 9 emitted from the laser chip 6 is reflected by the infrared transmitting plate 2 and becomes return light 10, which is transmitted to the laser chip 6. It may be injected.

[Problem that the invention seeks to solve]

As described above, when the return light 10 reflected by the infrared transmitting plate 2 is incident on the laser chip 6, so-called reflected wave noise is generated.

This is because when the returned light 10 enters the laser chip 6, the carrier concentration changes, which changes the refractive index within the laser resonator and generates AM and FM noise. If this happens, the sensitivity of highly sensitive gas observation systems will decrease.

The present invention reduces the influence of returned light in this type of optical semiconductor device, and prevents reflected wave noise from occurring.

[Means for solving problems]

The optical semiconductor device of the present invention includes: a cooling container having a window made of a first infrared transmitting plate; an optical semiconductor element disposed in the cooling container facing the infrared transmitting plate; A second infrared transmitting plate is provided between the semiconductor element and the infrared transmitting plate so as to be inclined with respect to the optical axis of the light emitted from the optical semiconductor element.

[Effect]

When the above means is adopted, the return light that is emitted from the optical semiconductor element, passes through the second infrared transmitting plate, and is reflected by the first infrared transmitting plate is reflected by the second infrared transmitting plate, so that the light The light does not enter the semiconductor element, so no reflected wave noise is generated.

〔Example〕

FIG. 1 is a cutaway side view of essential parts of one embodiment of the present invention, and FIG.
The same parts as those described with respect to the figures are indicated by the same symbols.

This embodiment is different from the conventional example shown in FIG. 11 (second infrared transmitting plate) is arranged in an inclined state with respect to the optical axis of the emitted light 9 from the laser chip 6.

That is, in the μs conventional example shown in FIG. An infrared transmitting plate 11, which is a second infrared transmitting plate, is attached to the front surface of the camera. Incidentally, this infrared transmitting plate 11 also
Similar to infrared transmitting plate 2, barium fluoride, germanium,
Silicon or the like may be used.

In this way, the return light 10 from the infrared transmitting plate 2 is reflected by the infrared transmitting plate 11 in the direction shown, and does not enter the laser chip 6.

Therefore, since no reflected wave noise is generated, this optical semiconductor device can maintain high sensitivity.

Further, in the above embodiment, the back surface of the infrared transmitting plate 11 which is the second infrared transmitting plate or the infrared transmitting plate 2 which is the first infrared transmitting plate, that is, facing the laser chip 6. It is advisable to apply an anti-reflective coating to the side facing the camera.

〔Effect of the invention〕

In the optical semiconductor device of the present invention, the optical axis of the light emitted from the optical semiconductor element is located between the first infrared transmitting plate, which is the window of the cooling container, and the optical semiconductor element facing the first infrared transmitting plate. The second infrared transmitting plate is arranged at a predetermined inclination relative to the second infrared transmitting plate.

Therefore, the infrared light emitted from the optical semiconductor element passes through the second and first infrared transmitting plates and is emitted to the outside, and
Even if a part of the infrared light is reflected by the first infrared transmitting plate and becomes return light, the returned light is reflected by the second infrared transmitting plate, so that it does not affect the optical semiconductor element. Since it is not incident, the generation of reflected wave noise can be suppressed to an extremely low level. Furthermore, in carrying out the present invention, only a second infrared transmitting plate is attached to the front surface of the cover, which was conventionally left open, so the device is considerably larger than the conventional optical semiconductor device. There will be no structural changes.

[Brief explanation of the drawing]

FIG. 1 is a cutaway side view of the main part of an embodiment of the present invention, and FIG. 2 is a cutaway side view of the main part of a conventional example. In the figure, 1 is a Dewar bottle which is a cooling container, 2 is an infrared transmission plate, 3 is a cooling base, 4 is a heat sink, 5 is a ceramic layer, 6 is a laser chip, 7 is a ribbon wire, 8 9 indicates a cover, 9 indicates an emitted infrared light, 10 indicates a returned light, and 11 indicates an infrared transmitting plate.

Claims (1)

[Claims] a cooling container having a window made of a first infrared transmitting plate; an optical semiconductor element disposed in the cooling container to face the infrared transmitting plate; and the optical semiconductor element and the infrared transmitting plate. an optical semiconductor device, comprising: a second infrared transmitting plate disposed between the optical semiconductor device and the second infrared transmitting plate in an inclined state with respect to the optical axis of the light emitted from the optical semiconductor element.