Reservoir computing device using external-feedback laser system

Patent metadata

Field	Value
Publication number	US-9996794-B2
Application number	US-201715792852-A
Country	US
Kind code	B2
Filing date	Oct 25, 2017
Priority date	Jun 3, 2016
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

Various Reservoir Computing systems and a method performed by a Reservoir Computing system are provided. A Reservoir Computing system includes a laser for emitting light. The Reservoir Computing system further includes a mirror for reflecting external feedback light back to the laser. The Reservoir Computing system also includes a modulator for modulating the external feedback light reflected back to the laser. The Reservoir Computing system additionally includes a photo-detector for converting a laser output signal to an electrical signal.

First claim

What is claimed is:

1. A Reservoir Computing system, comprising:
a laser for emitting light;
a mirror for reflecting external feedback light back to the laser;
a modulator for modulating the external feedback light reflected back to the laser; and
a photo-detector for converting a laser output signal to an electrical signal.

2. The Reservoir Computing system of claim 1 , wherein the modulator modulates the external feedback light by changing a reflectivity of the mirror.

3. The Reservoir Computing system of claim 2 , wherein the reflectivity of the mirror is changed by modulating a refractive index of the mirror using a non-linear optical effect.

4. The Reservoir Computing system of claim 2 , wherein the reflectivity of the mirror is changed by modulating a refractive index of the mirror based on electric current variation.

5. The Reservoir Computing system of claim 1 , wherein the mirror comprises a Distributed Bragg Reflector.

6. The Reservoir Computing system of claim 1 , wherein the modulator modulates the external feedback light by changing an effective optical path length between the laser and the photo detector.

7. The Reservoir Computing system of claim 6 , wherein the modulator comprises an optical switch for selectively enabling one of multiple available optical paths, each having a different effective optical path length between the laser and the photo detector.

8. The Reservoir Computing system of claim 7 , wherein the optical switch comprises a Mach-Zehnder interferometer.

9. The Reservoir Computing system of claim 7 , wherein at least one of the multiple available optical paths comprises an optical delay loop.

10. The Reservoir Computing system of claim 1 , further comprising an optical waveguide for guiding the laser output signal.

11. The Reservoir Computing system of claim 1 , wherein the optical waveguide comprises a photonic crystal.

12. The Reservoir Computing system of claim 1 , wherein the laser is a distributed feedback laser, and the laser, the mirror, the modulator, and the photo-detector are integrated on a Silicon photonics chip.

13. The Reservoir Computing system of claim 1 , wherein the laser is a semiconductor laser.

14. The Reservoir Computing system of claim 1 , wherein the laser operates at a pump power that is above a lasing threshold of the laser and below two times a pumping rate of the laser.

15. The Reservoir Computing system of claim 1 , wherein the laser is a non-semiconductor laser.

16. The Reservoir Computing system of claim 1 , further comprising a controller for applying a learning algorithm to the electrical signal.

17. A method performed by a Reservoir Computing system, the method comprising:
emitting, by a laser, light;
reflecting, by a mirror, external feedback light back to the laser;
modulating, by a modulator, the external feedback light reflected back to the laser; and
converting, by a photo-detector, a laser output signal to an electrical signal.

18. The method of claim 17 , wherein said modulating step modulates the external feedback light by changing a reflectivity of the mirror.

19. The method of claim 18 , wherein the reflectivity of the mirror is changed by modulating a refractive index of the mirror using a non-linear optical effect.

20. The method of claim 18 , wherein the reflectivity of the mirror is changed by modulating a refractive index of the mirror based on electric current variation.

Assignees

• IBM

Inventors

• Nakano Daiju
• Takeda Seiji
• Yamane Toshiyuki

Classifications

• G06N3/044

  Recurrent networks, e.g. Hopfield networks · CPC title

• G06N3/09

  Supervised learning · CPC title

• G02F1/3136

  of interferometric switch type · CPC title

• G02F2001/0154

  Physics · mapped topic

• H04Q2011/0026

  using free space propagation (e.g. lenses, mirrors) · CPC title