TWO-DIMENSIONAL PHOTONIC CRYSTAL SURFACE EMITTING LASER

• US 20170256911A1
• Filed: 08/28/2015
• Published: 09/07/2017
• Est. Priority Date: 08/29/2014
• Status: Active Grant

• Current Assignee: Hamamatsu Photonics KK, Kyoto University, Mitsubishi Electric Corporation, ROHM Co., Ltd.
• Original Assignee: Hamamatsu Photonics KK, Kyoto University, Mitsubishi Electric Corporation, ROHM Co., Ltd.
• Inventors: NODA, Susumu, KITAGAWA, Hitoshi, LIANG, Yong, WATANABE, Akiyoshi, HIROSE, Kazuyoshi
• Granted Patent: US 10,461,501 B2
• Time in Patent Office: Days
• CPC Class Codes: H01S 5/04253 having specific optical properties, e.g. transparent electrodes
• CPC Class Codes: H01S 5/04254 characterised by the shape
• CPC Class Codes: H01S 5/0654 Single longitudinal mode emission
• CPC Class Codes: H01S 5/11 Comprising a photonic bandgap structure
• CPC Class Codes: H01S 5/18319 comprising a periodical structure in lateral directions
• CPC Class Codes: H01S 5/185 having only horizontal cavities, e.g. horizontal cavity surface-emitting lasers [HCSEL] comprising a photonic bandgap structure H01S5/11
• CPC Class Codes: H01S 5/34313 with a well layer having only As as V-compound, e.g. AlGaAs, InGaAs
• CPC Class Codes: H01S 5/34353 based on (AI)GaAs

Abstract

A two-dimensional photonic crystal surface emitting laser capable of improving characteristics of light to be emitted, particularly optical output , which includes: a two-dimensional photonic crystal including a plate-shaped base member and modified refractive index regions where the modified refractive index regions have a refractive index different from that of the plate-shaped base member and are two-dimensionally and periodically arranged in the base member; an active layer provided on one side of the two-dimensional photonic crystal; and a first electrode and a second electrode provided sandwiching the two-dimensional photonic crystal and the active layer for supplying current to the active layer, where the second electrode covers a region equal to or wider than the first electrode, wherein the first electrode is formed so as to supply the current to the active layer with a different density depending on the in-plane position on the first electrode.

Claims

1. A two-dimensional photonic crystal surface emitting laser, comprising:

a two-dimensional photonic crystal including a plate-shaped base member and modified refractive index regions where the modified refractive index regions have a refractive index different from that of the plate-shaped base member and are two-dimensionally and periodically arranged in the base member;

an active layer provided on one side of the two-dimensional photonic crystal; and

a first electrode and a second electrode provided sandwiching the two-dimensional photonic crystal and the active layer for supplying current to the active layer where the second electrode covers a range equal to or wider than the first electrode,

wherein the first electrode is formed so as to supply the current to the active layer with a different density depending on an in-plane position on the first electrode.

2. The two-dimensional photonic crystal surface emitting laser according to claim 1, wherein the first electrode is formed so as to supply the current to the active layer where the distribution has a highest density at a center of the in-plane position.

3. The two-dimensional photonic crystal surface emitting laser according to claim 1, wherein the first electrode includes a conductor formed in a mesh shape.

4. The two-dimensional photonic crystal surface emitting laser according to claim 3, wherein an interval between lines of the mesh is 1.4 times or less wider than current spreading in an in-plane direction of the active layer.

5. The two-dimensional photonic crystal surface emitting laser according to claim 3, wherein the first electrode includes regions having different area ratios of the conductor in the mesh.

6. The two-dimensional photonic crystal surface emitting laser according to claim 5, wherein the area ratio in each of the regions gradually decreases as a position is apart from the center of the in-plane position of the first electrode.

7. The two-dimensional photonic crystal surface emitting laser according to claim 6, wherein a region including the center in the first electrode consists only of the conductor.

8. The two-dimensional photonic crystal surface emitting laser according to claim 3, wherein the area ratio of the conductor in the mesh of the first electrode continuously changes depending on a position.

9. The two-dimensional photonic crystal surface emitting laser according to claim 8, wherein the area ratio of the conductor in the mesh gradually decreases as a position is apart from the center of the in-plane position of the first electrode.

10. The two-dimensional photonic crystal surface emitting laser according to claim 1, wherein the first electrode includes ring-shaped conductors arranged concentric-circularly, and a connective part for electrically connecting the ring-shaped conductors to each other.

11. The two-dimensional photonic crystal surface emitting laser according to claim 1, wherein the first electrode is divided into regions, the regions comprising sub-electrodes electrically insulated from each other.

12. The two-dimensional photonic crystal surface emitting laser according to claim 11, wherein different power sources are connected to the respective sub-electrodes.

13. The two-dimensional photonic crystal surface emitting laser according to claim 2, wherein the first electrode includes a conductor formed in a mesh shape.

14. The two-dimensional photonic crystal surface emitting laser according to claim 4, wherein the first electrode includes regions having different area ratios of the conductor in the mesh.

15. The two-dimensional photonic crystal surface emitting laser according to claim 4, wherein the area ratio of the conductor in the mesh of the first electrode continuously changes depending on a position.

16. The two-dimensional photonic crystal surface emitting laser according to claim 2, wherein the first electrode includes ring-shaped conductors arranged concentric-circularly, and a connective part for electrically connecting the ring-shaped conductors to each other.

17. The two-dimensional photonic crystal surface emitting laser according to claim 2, wherein the first electrode is divided into regions, the regions comprising sub-electrodes electrically insulated from each other.