Semiconductor laser, electronic apparatus, and method of driving semiconductor laser

Patent metadata

Field	Value
Publication number	US-10680406-B2
Application number	US-201716323253-A
Country	US
Kind code	B2
Filing date	Jul 12, 2017
Priority date	Aug 25, 2016
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

In a semiconductor laser according to an embodiment of the present disclosure, a ridge part has a structure in which a plurality of gain regions and a plurality of Q-switch regions are each disposed alternately with each of separation regions being interposed therebetween in an extending direction of the ridge part. The separation regions each have a separation groove that separates from each other, by a space, the gain region and the Q-switch region adjacent to each other. The separation groove has a bottom surface at a position, in a second semiconductor layer, higher than a part corresponding to a foot of each of both sides of the ridge part.

First claim

The invention claimed is:

1. A semiconductor laser, comprising:
a semiconductor substrate;
a first semiconductor layer of a first conductivity type;
an active layer;
a second semiconductor layer of the first conductivity type;
a third semiconductor layer of a second conductivity type, wherein the first semiconductor layer of the first conductivity type, the active layer, the second semiconductor layer of the first conductivity type, and the third semiconductor layer of the second conductivity type are in respective order on the semiconductor substrate; and
a ridge part in the second semiconductor layer and the third semiconductor layer, wherein
the ridge part extends in a stacked in-plane direction,
the ridge part has a structure in which a plurality of gain regions and a plurality of Q-switch regions are each disposed alternately and a separation region is interposed between each gain region of the plurality of gain regions and each Q-switch region of the plurality of Q-switch regions,
the separation region is interposed in an extending direction of the ridge part,
the separation region includes a separation groove that separates, by a space, a gain region of the plurality of gain regions from a Q switch region of the plurality of Q-switch regions adjacent to the gain region, and
the separation groove has a bottom surface at a position, in the second semiconductor layer, higher than a part corresponding to a foot of each side of both sides of the ridge part.

2. The semiconductor laser according to claim 1 , wherein
the second semiconductor layer includes a first different-composition-ratio semiconductor layer having a composition ratio different from a composition ratio of a remaining part of the second semiconductor layer, and
the bottom surface of the separation groove is a portion of a top surface of the first different-composition-ratio semiconductor layer.

3. The semiconductor laser according to claim 2 , wherein
the second semiconductor layer includes a second different-composition-ratio semiconductor layer having a composition ratio different from the composition ratio of the remaining part of the second semiconductor layer, and
a top surface of the part corresponding to the foot of each side of both the sides of the ridge part is a portion of a top surface of the second different-composition-ratio semiconductor layer.

4. The semiconductor laser according to claim 3 , wherein each of the bottom surface of the separation groove and the top surface of the part corresponding to the foot of each side of both the sides of the ridge part is a surface formed by wet etching.

5. The semiconductor laser according to claim 1 , wherein each Q-switch region of the plurality of Q-switch regions includes an interface between the second semiconductor layer and the third semiconductor layer at a position higher than the part corresponding to the foot of each side of both the sides of the ridge part.

6. The semiconductor laser according to claim 1 , wherein
the second semiconductor layer includes a first impurity diffusion region of the second conductivity type at a part corresponding to each gain region of the plurality of gain regions, and
each gain region of the plurality of gain regions includes a p-n junction at a position lower than the part corresponding to the foot of each side of both the sides of the ridge part.

7. The semiconductor laser according to claim 6 , wherein
the second semiconductor layer includes a second impurity diffusion region of the second conductivity type at a part corresponding to each Q-switch region of the plurality of Q-switch regions, and
each Q-switch region of the plurality of Q-switch regions includes a p-n junction at a position lower than the part corresponding to the foot of each side of both the sides of the ridge part.

8. The semiconductor laser according to claim 1 , wherein, in the bottom surface of the separation groove, a height of a middle part in a width-direction of the ridge part is higher than a height of a part close to the foot of each side of both the sides of the ridge part.

9. The semiconductor laser according to claim 8 , wherein, in the separation groove, a width of the middle part in the width-direction of the ridge part is narrower than a width of the part close to the foot of each side of both the sides of the ridge part.

10. The semiconductor laser according to claim 1 , wherein, in the separation groove, a width of a middle part in a width-direction of the ridge part is narrower than a width of a part close to the foot of each side of both the sides of the ridge part.

11. The semiconductor laser according to claim 1 , wherein
in each gain region of the plurality of gain regions, an end surface facing the separation region includes one or more convex shapes in a width-direction of the ridge part, and
in each Q-switch region of the plurality of Q-switch regions, an end surface facing the separation region includes one or more concave shapes that approximately follow the one or more convex shapes.

12. The semiconductor laser according to claim 1 , wherein, in each gain region of the plurality of gain regions and each Q-switch region of the plurality of Q-switch regions, an end surface facing the separation region has a configuration having a distribution of a refractive index from the gain region of the plurality of gain regions to the Q-switch region of the plurality of Q-switch regions.

13. The semiconductor laser according to claim 12 , wherein, in one or both of each gain region of the plurality of gain regions and each Q-switch region of the plurality of Q-switch regions, the end surface facing the separation region has one of a convex shape, a concave shape, or a concavo-convex shape in a width-direction of the ridge part.

14. An electronic apparatus, comprising:
a semiconductor laser as a light source, the semiconductor laser including:
a semiconductor substrate;
a first semiconductor layer of a first conductivity type;
an active layer;
a second semiconductor layer of the first conductivity type;
a third semiconductor layer of a second conductivity type, wherein the first semiconductor layer of the first conductivity type, the active layer, the second semiconductor layer of the first conductivity type, and the third semiconductor layer of the second conductivity type are in respective order on the semiconductor substrate; and
a ridge part in the second semiconductor layer and the third semiconductor layer, wherein
the ridge part extends in a stacked in-plane direction,
the ridge part has a structure in which a plurality of gain regions and a plurality of Q-switch regions are each disposed alternately and a separation region is interposed between each gain region of the plurality of gain regions and each Q-switch region of the plurality of Q-switch regions,
the separation region is interposed in an extending direction of the ridge part,
the separation region includes a separation groove that separates, by a space, a gain region of the plurality of gain regions from a Q switch region of the plurality of Q-switch regions adjacent to the gain region, and
the separation groove has a bottom surface at a position, in the second semiconductor layer, higher than a part corresponding to a foot of each side of both sides of the ridge part.

15. The electronic apparatus according to claim 14 , further comprising a drive section configured to:
drive the semiconductor laser;
apply a forward bias pulse voltage to the gain region of the plurality of gain regions; and
apply a reverse bias to the Q-switch region of the plurality of

Assignees

• Sony Corp

Inventors

• Ono Tomoki
• Oohata Toyoharu
• Koyama Takahiro
• Takiguchi Mikio
• Tanaka Masayuki

Classifications

• H01S5/1003

  Waveguide having a modified shape along the axis, e.g. branched, curved, tapered, voids · CPC title

• H01S5/0625

  in multi-section lasers · CPC title

• H01S5/06253

  Pulse modulation · CPC title

• H01S5/22

  having a ridge or stripe structure · CPC title

• H01S5/0206

  Substrates, e.g. growth, shape, material, removal or bonding; (specific crystal orientation H01S5/3202) · CPC title