Semiconductor device

• US 20060221438A1
• Filed: 10/25/2005
• Published: 10/05/2006
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Akiyama, Tomoyuki
• Granted Patent: US 7,808,698 B2
• Time in Patent Office: Days
• US Class Current: 359/344
• CPC Class Codes: H01S 5/026 Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers stabilisation of output H01S5/06
• CPC Class Codes: H01S 5/0262 Photo-diodes, e.g. transceiver devices, bidirectional devices H01S5/0265 takes precedence
• CPC Class Codes: H01S 5/0264 for monitoring the laser-output
• CPC Class Codes: H01S 5/1085 Oblique facets
• CPC Class Codes: H01S 5/2022 Absorbing region or layer parallel to the active layer, e.g. to influence transverse modes
• CPC Class Codes: H01S 5/2206 based on III-V materials
• CPC Class Codes: H01S 5/227 Buried mesa structure ; Striped active layer
• CPC Class Codes: H01S 5/50 Amplifier structures not provided for in groups H01S5/02 - H01S5/30

Abstract

In a semiconductor device comprising a semiconductor optical amplifier, in order to allow a photodetector to be integrated without causing power loss at a low cost, the semiconductor device comprises a semiconductor substrate, a semiconductor optical waveguide, at least partly capable of functioning as a semiconductor optical amplifier, to guide signal light, and a photodetector provided in a region other than a region where the semiconductor optical waveguide is provided, wherein the semiconductor optical waveguide and the photodetector are integrated on the semiconductor substrate.

Claims

1. A semiconductor device comprising:

a semiconductor substrate;

a semiconductor optical waveguide, at least partly capable of functioning as a semiconductor optical amplifier, to guide signal light; and

a photodetector provided in a region other than a region where said semiconductor optical waveguide is provided,

wherein said semiconductor optical waveguide and said photodetector are integrated on said semiconductor substrate.

2. A semiconductor device according to claim 1, comprising, as said photodetector, an output photodetector which is provided at a position where light reflected on the output side can be detected.

3. A semiconductor device according to claim 2, wherein said output photodetector is provided at a position where light reflected on the output-side end face of said device can be detected.

4. A semiconductor device according to claim 2, further comprising an optical waveguide for detecting output light, adapted to guide light reflected on the output side to said output photodetector.

5. A semiconductor device according to claim 1, comprising, as said photodetector, an input photodetector provided at a position where light radiated from the wall face of said semiconductor optical waveguide without being coupled to said semiconductor optical waveguide on the input side can be detected.

6. A semiconductor device according to claim 5, further comprising an optical waveguide for detecting input light, adapted to guide non-guided radiated light from the wall face of said semiconductor optical waveguide to said input photodetector on the input side.

7. A semiconductor device according to claim 1, comprising, as said photodetector, an input photodetector provided along an input side portion of said semiconductor optical waveguide in such a manner as to enable the detection of non-guided radiated light from the wall face of said semiconductor optical waveguide without being guided by said semiconductor optical waveguide.

8. A semiconductor device according to claim 1, comprising, as said photodetector, an output photodetector provided along an output side portion of said semiconductor optical waveguide in such a manner as to enable the detection of non-guided radiated light from the wall face of said semiconductor optical waveguide without being guided by said semiconductor optical waveguide.

9. A semiconductor device according to claim 1, wherein said photodetector has the same waveguide structure as said semiconductor optical waveguide, and said semiconductor device is configured such that a forward bias voltage is applied to the semiconductor optical amplifier portion of said semiconductor optical waveguide and a reverse bias voltage is applied to said photodetector.

10. A semiconductor device according to claim 1, further comprising a light absorbing region capable of absorbing non-guided radiated light from the wall face of said semiconductor optical waveguide without being guided by said semiconductor optical waveguide.

11. A semiconductor device according to claim 10, wherein said light absorbing region has the same waveguide structure as said semiconductor optical waveguide, and said semiconductor device is configured such that a forward bias voltage is applied to the semiconductor optical amplifier portion of said semiconductor optical waveguide and a reverse bias voltage is applied to said light absorbing region or no bias voltage is applied thereto.

12. A semiconductor device according to claim 1, further comprising an amplifying region for amplifying light guided to said photodetector.

13. A semiconductor device according to claim 12, wherein said amplifying region has the same waveguide structure as said semiconductor optical waveguide.

14. A semiconductor device according to claim 1, wherein said semiconductor optical waveguide is formed obliquely to an end face of said device.