Optical phase-sensitive amplifier with raman amplifier intermediate stage

Patent metadata

Field	Value
Publication number	US-9837788-B2
Application number	US-201514958160-A
Country	US
Kind code	B2
Filing date	Dec 3, 2015
Priority date	Mar 6, 2015
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A method and system for amplifying optical signals includes generating idler signals for input signals using an optical pump at a first non-linear element (NLE). An intermediate stage including a Raman amplifier performs pump amplification using the output from the first NLE along a single optical path. Optical power monitoring of the input signals may be used for power equalization. The intermediate stage may include a wavelength selective switch for a certain degree of phase modulation. The phase-sensitive amplified signal is generated at a second NLE using the optical pump. Optical power monitoring of the input signals may be used for power equalization and other control functions to achieve low-noise operation.

First claim

What is claimed is:

1. An optical phase-sensitive amplifier, comprising:
an idler stage enabled to:
receive, as input, an optical signal and an optical pump light; and
output the optical signal, the optical pump light, and an idler signal corresponding to the optical signal;

an intermediate stage including a Raman amplifier enabled to:
receive, as input from the idler stage, the optical signal, the optical pump light, and the idler signal;
based on a Raman optical pump in the Raman amplifier, selectively amplify the optical pump light and the idler signal; and

an amplification stage enabled to:
receive, as input from the intermediate stage, the optical signal, the amplified optical pump light, and the amplified idler signal; and
amplify the optical signal.

2. The optical phase-sensitive amplifier of claim 1 , wherein the idler stage, the intermediate stage, and the amplification stage comprise a single optical path over which the optical signal, the optical pump light, and the idler signal propagate.

3. The optical phase-sensitive amplifier of claim 1 , wherein the intermediate stage enabled to selectively amplify the optical pump light and the idler signal further comprises the Raman amplifier enabled to:
amplify the idler signal to correspond in optical power to the optical signal.

4. The optical phase-sensitive amplifier of claim 1 , wherein the intermediate stage is further enabled to:
modify an optical gain for amplifying the optical signal in the amplification stage by modifying an optical power of the Raman optical pump.

5. The optical phase-sensitive amplifier of claim 1 , further comprising:
an optical power monitor to measure an optical signal-to-noise ratio (OSNR) of the optical signal received by the optical phase-sensitive amplifier; and
wherein the intermediate stage is further enabled to modify the optical power of the Raman optical pump based on the OSNR of the optical signal.

6. The optical phase-sensitive amplifier of claim 5 , wherein the OSNR of the optical signal received by the optical phase-sensitive amplifier is smaller than the OSNR of the optical signal after being amplified at the amplification stage.

7. The optical phase-sensitive amplifier of claim 1 , wherein the intermediate stage further comprises:
a wavelength selective switch (WSS) to respectively modify at least one of a phase and an amplitude, for at least one of the optical signal, the optical pump light, and the idler signal.

8. The optical phase-sensitive amplifier of claim 7 , wherein the WSS respectively modifies the phase for at least one of the optical signal, the optical pump light, and the idler signal to modify an optical gain for amplifying the optical signal in the amplification stage.

9. The optical phase-sensitive amplifier of claim 7 , wherein the WSS aligns the phase among the optical signal, the optical pump light, and the idler signal.

10. The optical phase-sensitive amplifier of claim 1 , wherein the intermediate stage enabled to selectively amplify the optical pump light and the idler signal further comprises the Raman amplifier enabled to:
amplify the idler signal to exceed an optical power of the optical signal prior to the amplification stage.

11. A method for optical phase-sensitive amplification, the method comprising:
in an idler stage:
receiving, as input, an optical signal and an optical pump light; and
outputting the optical signal, the optical pump light, and an idler signal corresponding to the optical signal;

in an intermediate stage including a Raman amplifier:
receiving, as input from the idler stage, the optical signal, the optical pump light, and the idler signal;
based on a Raman optical pump in the Raman amplifier, selectively amplifying the optical pump light and the idler signal; and

in an amplification stage:
receiving, as input from the intermediate stage, the optical signal, the amplified optical pump light, and the amplified idler signal; and
amplifying the optical signal.

12. The method of claim 11 , wherein the idler stage, the intermediate stage, and the amplification stage comprise a single optical path over which the optical signal, the optical pump light, and the idler signal propagate.

13. The method of claim 11 , wherein selectively amplifying the optical pump light and the idler signal in the intermediate stage further comprises:
amplifying, by the Raman amplifier, the idler signal to correspond in optical power to the optical signal.

14. The method of claim 11 , further comprising:
modifying, in the intermediate stage, an optical power of the Raman optical pump to modify an optical gain for amplifying the optical signal in the amplification stage.

15. The method of claim 11 , further comprising:
measuring, using an optical power monitor, an optical signal-to-noise ratio (OSNR) of the optical signal received by the optical phase-sensitive amplifier; and
modifying, in the intermediate stage, the optical power of the Raman optical pump based on the OSNR of the optical signal.

16. The method of claim 11 , wherein the OSNR of the optical signal received by the optical phase-sensitive amplifier is smaller than the OSNR of the optical signal after being amplified at the amplification stage.

17. The method of claim 11 , further comprising:
respectively modifying, at a wavelength selective switch (WSS) included in the intermediate stage, at least one of a phase and an amplitude, for at least one of the optical signal, the optical pump light, and the idler signal.

18. The method of claim 17 , wherein the respectively modifying the phase further comprises:
respectively modifying the phase for at least one of the optical signal, the optical pump light, and the idler signal to modify an optical gain for amplifying the optical signal in the amplification stage.

19. The method of claim 17 , wherein the respectively modifying the phase further comprises:
aligning the phase among the optical signal, the optical pump light, and the idler signal.

20. The method of claim 11 , wherein the selectively amplifying the optical pump light and the idler signal further comprises:
amplifying, at the Raman amplifier, the idler signal to exceed an optical power of the optical signal prior to the amplification stage.

Assignees

• Fujitsu Ltd

Inventors

• Akasaka Youichi
• Sekiya Motoyoshi

Classifications

• H04B10/2916

  using Raman or Brillouin amplifiers · CPC title

• G02F1/31

  Digital deflection, {i.e. optical switching}(G02F1/33 takes precedence) · CPC title

• H01S3/302 Primary

  in an optical fibre · CPC title

• H01S3/06754

  Fibre amplifiers (H01S3/06708 takes precedence) · CPC title

• H01S2301/03

  Suppression of nonlinear conversion, e.g. specific design to suppress for example stimulated brillouin scattering [SBS], mainly in optical fibres in combination with multimode pumping · CPC title