Optical semiconductor device, optical semiconductor device array, and optical transmitter module

Patent metadata

Field	Value
Publication number	US-9728938-B2
Application number	US-201414486047-A
Country	US
Kind code	B2
Filing date	Sep 15, 2014
Priority date	Oct 2, 2013
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

An optical semiconductor device includes: an active region which includes an active layer which produces light when current is injected therein, a first diffraction grating layer having a first diffraction grating with a prescribed grating period, and a phase shift portion formed within the first diffraction grating layer, wherein the phase shift portion provides a phase shift not smaller than 1.5π but not larger than 1.83π; and a distributed reflection mirror region which is optically coupled to a first end of the active region as viewed along a direction of an optical axis, and which includes a second diffraction grating which reflects the light produced by the active region back into the active region.

First claim

What is claimed is:

1. A distributed reflection laser, comprising:
an active region which includes an active layer which produces light when current is injected therein, a first diffraction grating layer having a first diffraction grating with a prescribed grating period, and a grating phase shift portion formed within the first diffraction grating layer, wherein the grating phase shift portion provides a grating phase shift not smaller than 1.57π but not larger than 1.83π and
a first distributed reflection mirror region which is optically coupled to a first end of the active region as viewed along a direction of an optical axis, and which includes a second diffraction grating which has the same grating period as that of the first diffraction grating and reflects the light produced by the active region back into the active region; and
a second distributed reflection mirror region which is optically coupled to a second end of the active region as viewed along the direction of the optical axis, and which includes a third diffraction grating which has the same grating period as that of the first diffraction grating and reflects the light produced by the active region back into the active region.

2. The distributed reflection laser according to claim 1 , wherein the depth of grooves forming the second diffraction grating is the same as the depth of grooves forming the first diffraction grating.

3. The distributed reflection laser according to claim 1 , wherein the depth of grooves forming the second diffraction grating is greater than the depth of grooves forming the first diffraction grating.

4. The distributed reflection laser according to claim 1 , wherein the distributed reflection laser is provided with an antireflective layer at both ends as viewed along the direction of the optical axis.

5. The distributed reflection laser according to claim 1 , wherein the grating phase shift that the phase shift portion provides is larger than 1.5π.

6. A distributed reflection laser array, comprising:
a substrate;
a first distributed reflection laser unit arranged on the substrate, the first distributed reflection laser unit comprising
a first active region which includes a first active layer which produces light when current is injected therein, a first diffraction grating layer having a first diffraction grating with a first grating period, and a first grating phase shift portion formed within the first diffraction grating layer, wherein the first grating phase shift portion provides a grating phase shift not smaller than 1.5π but not larger than 1.83π,
a first distributed reflection mirror region which is optically coupled to a first end of the first active region, and which includes a second diffraction grating which has the same grating period as that of the first diffraction grating and reflects the light produced by the first active region back into the first active region, and
a second distributed reflection mirror region which is optically coupled to a second end of the first active region as viewed along the direction of the optical axis, and which includes a third diffraction grating which has the same grating period as that of the first diffraction grating and reflects the light produced by the first active region back into the first active region; and
a second distributed reflection laser unit arranged side by side with the first distributed reflection laser unit on the substrate, the second distributed reflection laser unit comprising
a second active region which includes a second active layer which produces light when current is injected therein, a fourth diffraction grating layer having a fourth diffraction grating with a second grating period, and a second grating phase shift portion formed within the fourth diffraction grating layer, wherein the second grating phase shift portion provides a grating phase shift not smaller than 1.57π but not larger than 1.837π, and
a third distributed reflection mirror region which is optically coupled to a first end of the second active region, and which includes a fifth diffraction grating which has the same grating period as that of the fourth diffraction grating and reflects the light produced by the second active region back into the second active region; and
a fourth distributed reflection mirror region which is optically coupled to a second end of the second active region as viewed along the direction of the optical axis, and which includes a sixth diffraction grating which has the same grating period as that of the fourth diffraction grating and reflects the light produced by the second active region back into the second active region.

7. An optical transmitter module, comprising:
a distributed reflection laser, the distributed reflection laser comprising
an active region which includes an active layer which produces light when current is injected therein, a first diffraction grating layer having a first diffraction grating with a prescribed grating period, and a grating phase shift portion formed within the first diffraction grating layer, wherein the grating phase shift portion provides a grating phase shift not smaller than 1.57π but not larger than 1.83π,
a first distributed reflection mirror region which is optically coupled to a first end of the active region, and which includes a second diffraction grating which has the same grating period as the first diffraction grating and reflects the light produced by the active region back into the active region, and
a second distributed reflection mirror region which is optically coupled to a second end of the active region as viewed along the direction of the optical axis, and which includes a third diffraction grating which has the same grating period as the first diffraction grating and reflects the light produced by the active region back into the active region; and
a driving unit which injects current into the active layer.

8. The distributed reflection laser according to claim 1 , wherein the distributed reflection laser comprises an electrode layer for injecting current into the active region and no current is injected into the first and second distributed reflection mirror regions.

9. The distributed reflection laser array according to claim 6 , wherein the first distributed reflection laser unit comprises a first electrode layer for injecting current into the first active region, and the second distributed reflection laser unit comprises a second electrode layer for injecting current into the second active region and no current is injected into the first, second, third and fourth distributed reflection mirror regions.

10. The optical transmitter module according to claim 7 , wherein the distributed reflection layer comprises an electrode layer for injecting current into the active region and no current is injected into the first and second distributed reflection mirror regions.

Assignees

• Fujitsu Ltd

Inventors

• Matsuda Manabu
• Uetake Ayahito

Classifications

• H01S5/4012

  Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms · CPC title

• H01S5/22

  having a ridge or stripe structure · CPC title

• H01S5/4087

  emitting more than one wavelength · CPC title

• H01S5/125 Primary

  Distributed Bragg reflector [DBR] lasers · CPC title

• H01S5/124

  incorporating phase shifts · CPC title