Optical switch

• US 10,389,353 B2
• Filed: 06/16/2017
• Issued: 08/20/2019
• Est. Priority Date: 06/30/2016
• Status: Active Grant

• Current Assignee: Fujifilm Business Innovation Corp. (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Kondo, Takashi
• Primary Examiner(s): Lee, John R
• Application Number:
  US15/625,018
• Publication Number:
  US 20180006645A1
• Time in Patent Office: 795 Days
• CPC Class Codes: H01L 31/1113 the device being a photothyristor
• CPC Class Codes: H01L 31/125 Composite devices with photosensitive elements and electroluminescent elements within one single body
• CPC Class Codes: H03K 17/79 controlling bipolar semiconductor switches with more than two PN-junctions, or more than three electrodes, or more than one electrode connected to the same conductivity region

Abstract

An optical switch includes: a photothyristor that is switched from an off state to an on state by incident light; a light-emitting element that emits outgoing light when the photothyristor is in the on state; and a tunnel junction layer or a III-V compound layer having metallic conductivity. The tunnel junction layer or the III-V compound layer is disposed between the photothyristor and the light-emitting element.

Claims

1. An optical switch comprising:

a photothyristor configured to be switched from an off state to an on state by incident light;

a light-emitting element configured to emit outgoing light when the photothyristor is in the on state; and

a tunnel junction layer or a III-V compound layer having metallic conductivity, the tunnel junction layer or the III-V compound layer being disposed between the photothyristor and the light-emitting element.

2. The optical switch according to claim 1, wherein the photothyristor includes a gate layer and a control electrode disposed on the gate layer.

3. The optical switch according to claim 1, wherein the light-emitting element includes a semiconductor layer, and the photothyristor includes a voltage reduction layer having a smaller band gap energy than the semiconductor layer of the light-emitting element.

4. The optical switch according to claim 2, wherein the light-emitting element includes a semiconductor layer, and the photothyristor includes a voltage reduction layer having a smaller band gap energy than the semiconductor layer of the light-emitting element.

5. The optical switch according to claim 1, wherein the light-emitting element has a confined current path.

6. The optical switch according to claim 2, wherein the light-emitting element has a confined current path.

7. The optical switch according to claim 3, wherein the light-emitting element has a confined current path.

8. The optical switch according to claim 4, wherein the light-emitting element has a confined current path.

9. The optical switch according to claim 1, wherein the photothyristor has an opening that is provided in a path configured to output the outgoing light from the light-emitting element.

10. The optical switch according to claim 2, wherein the photothyristor has an opening that is provided in a path configured to output the outgoing light from the light-emitting element.

11. The optical switch according to claim 3, wherein the photothyristor has an opening that is provided in a path configured to output the outgoing light from the light-emitting element.

12. The optical switch according to claim 4, wherein the photothyristor has an opening that is provided in a path configured to output the outgoing light from the light-emitting element.

13. The optical switch according to claim 5, wherein the photothyristor has an opening that is provided in a path configured to output the outgoing light from the light-emitting element.

14. The optical switch according to claim 6, wherein the photothyristor has an opening that is provided in a path configured to output the outgoing light from the light-emitting element.

15. The optical switch according to claim 7, wherein the photothyristor has an opening that is provided in a path configured to output the outgoing light from the light-emitting element.

16. The optical switch according to claim 8, wherein the photothyristor has an opening that is provided in a path configured to output the outgoing light from the light-emitting element.

17. The optical switch according to claim 9, wherein the opening of the photothyristor has a side wall that is inclined to receive the incident light.

18. The optical switch according to claim 1, wherein the photothyristor has a surface configured to receive the incident light, the photothyristor including an electrode formed on the surface, the surface having a portion that is not covered with the electrode.

19. The optical switch according to claim 1, wherein the light-emitting element includes a light-emitting layer, and the optical switch further comprises a distributed Bragg reflector layer that faces the light-emitting layer of the light-emitting element.

20. The optical switch according to claim 1, wherein the optical switch is configured such that, when the photothyristor is in the off state, a bias voltage is applied to the light-emitting element, the bias voltage maintaining a state in which light is outputted from the light-emitting element, the amount of the light being smaller than the amount of the outgoing light.

21. The optical switch according to claim 1, wherein the light-emitting element comprises a vertical-cavity surface-emitting laser, and

wherein the tunnel junction layer or the III-V compound layer are disposed outside of the vertical-cavity surface-emitting laser.

22. The optical switch according to claim 1, wherein the light-emitting element comprises a light-emitting layer having a quantum well structure,

wherein the light-emitting layer is configured to emit light toward a top of the light-emitting element, and

wherein the tunnel junction layer or the III-V compound layer are disposed below the light-emitting layer.