Raman amplifier system and method with integrated optical time domain reflectometer

Patent metadata

Field	Value
Publication number	US-9793986-B2
Application number	US-201514845351-A
Country	US
Kind code	B2
Filing date	Sep 4, 2015
Priority date	Sep 19, 2012
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

Raman amplifier systems and methods with an integrated Optical Time Domain Reflectometer (OTDR) for integrated testing functionality include an amplifier system, an OTDR and telemetry subsystem, and a method of operation. The OTDR and telemetry subsystem is configured to operate in an OTDR mode when coupled to a line in port and to operate in a telemetry mode when coupled to a line out port. The OTDR and telemetry subsystem enables on-demand fiber testing while also operating as a telemetry channel that is both a redundant optical service channel (OSC) and provides a mechanism to monitor Raman gain over time. The OTDR and telemetry subsystem minimizes cost and space by sharing major optical and electrical components between the integrated OTDR and other functions on the Raman amplifier.

First claim

What is claimed is:

1. A Raman amplifier module, with an integrated Optical Time Domain Reflectometer (OTDR), the Raman amplifier module comprising:
one or more Raman pumps, wherein the one or more Raman pumps are configured as a Raman amplifier;
a subsystem comprising a transmitter, a receiver, and circuitry, wherein the subsystem is configured to selectively operate as an OTDR and a telemetry channel based on configuration of a switch optically coupled to the transmitter and configuration of the circuitry, and wherein the transmitter has a wavelength that does not interfere with the one or more Raman pumps, but which experiences gain due to the one or more Raman pumps,
wherein the circuitry is configured to use the telemetry channel to measure gain due to Raman amplification in a fiber based on measurements with the one or more Raman pumps on and off to provide an estimate of Raman gain and communicate data with an adjacent Raman amplifier module.

2. The Raman amplifier module of claim 1 , wherein a wavelength of the transmitter is outside a range of wavelengths associated with the one or more Raman pumps, outside a range of wavelengths associated with Wavelength Division Multiplexed (WDM) channels, and different from a wavelength associated with an Optical Service Channel (OSC).

3. The Raman amplifier module of claim 1 , wherein, prior to activating the one or more Raman pumps, the OTDR is configured to perform a test, wherein corrective actions are performed responsive to the test,
wherein once the corrective actions are taken, the one or more Raman pumps are enabled and the subsystem is configured as the telemetry channel to continuously measure real-time Raman gain while concurrently providing a redundant Optical Service Channel (OSC) channel.

4. The Raman amplifier module of claim 3 , wherein, while the telemetry channel continuously measures the real-time Raman gain, responsive to detecting issues with the real-time gain, the subsystem is configured to switch to the OTDR to perform in-service fiber plant testing for any corrective action based thereon.

5. The Raman amplifier module of claim 1 , further comprising:
an Optical Service Channel (OSC) configured with the adjacent Raman amplifier module, wherein the data channel provides redundancy for the OSC.

6. The Raman amplifier module of claim 1 , further comprising:
a circulator optically coupled to a first port of the switch, a second fiber which is optically coupled to the one or more Raman pumps, and the receiver;
wherein, for the OTDR, the transmitter transmits via the circulator and the receiver receives a return signal via the circulator, and
wherein, for the telemetry channel, the switch is set to a second port optically coupled to the fiber and the transmitter transmits separate from the circulator and the receiver receives a telemetry signal from the adjacent Raman amplifier module via the circulator.

7. The Raman amplifier module of claim 1 , wherein the switch is configured to optically couple the transmitter to the fiber for the telemetry channel and to a second fiber for the OTDR, and wherein the one or more Raman pumps are optically coupled to the second fiber.

8. An optical subsystem, configured in a Raman amplifier, optical subsystem comprising:
a transmitter optically connected to a switch;
a receiver;
circuitry coupled to the transmitter and the receiver; and
a circulator with a first port optically connected to the switch, a second port optically connected to a fiber, and a third port optically connected to the receiver,
wherein the circuitry is configured to selectively operate as an Optical Time Domain Reflectometer (OTDR) and a telemetry channel based on configuration of the switch, transmitter, and the circuitry.

9. The optical subsystem of claim 8 , wherein a wavelength of the transmitter is outside a range of wavelengths associated with one or more Raman pumps, outside a range of wavelengths associated with Wavelength Division Multiplexed (WDM) channels, and different from a wavelength associated with an Optical Service Channel (OSC).

10. The optical subsystem of claim 8 , wherein the OTDR is configured to operate out-of-service and in-service relative to the Raman amplifier.

11. The optical subsystem of claim 10 , wherein the transmitter has a wavelength which does not interfere with the Raman amplifier, but which experiences gain due to the Raman amplifier, wherein a difference in measurements by the OTDR out-of-service and in-service provides an estimate of Raman gain associated with the Raman amplifier.

12. The optical subsystem of claim 8 , wherein, prior to activating the Raman amplifier, the OTDR is configured to perform a test, wherein corrective actions are performed responsive to the test,
wherein once the corrective actions are taken, the Raman amplifier is enabled and the optical subsystem is configured as the telemetry channel to continuously measure real-time Raman gain while concurrently providing a redundant Optical Service Channel (OSC) channel.

13. The optical subsystem of claim 12 , wherein, while the telemetry channel continuously measures the real-time Raman gain, responsive to detecting issues with the real-time gain, the subsystem is configured to switch to the OTDR to perform in-service fiber plant testing for any corrective action based thereon.

14. The optical subsystem of claim 8 , wherein the Raman amplifier comprises an Optical Service Channel (OSC) configured to communicate with an adjacent Raman amplifier module, wherein the telemetry channel provides redundancy for the OSC.

15. The optical subsystem of claim 8 , wherein the switch is configured to optically couple the transmitter to the fiber for the telemetry channel and to a second fiber for the OTDR, and wherein the one or more Raman pumps are optically coupled to the second fiber.

16. A Raman amplifier method, with an integrated Optical Time Domain Reflectometer (OTDR) in a Raman amplifier, the Raman amplifier method comprising:
providing one or more Raman pumps, wherein the one or more Raman pumps are configured as a Raman amplifier;
providing a subsystem comprising a transmitter, a receiver, and circuitry, wherein the subsystem is configured to selectively operate as an OTDR and a telemetry channel based on configuration of a switch optically coupled to the transmitter and configuration of the circuitry, and wherein the transmitter has a wavelength that does not interfere with the one or more Raman pumps, but which experiences gain due to the one or more Raman pumps; and
using the circuitry with the telemetry channel to measure gain due to Raman amplification in a fiber based on measurements one or more Raman pumps on and off to provide an estimate of Raman gain and to provide a data channel to an adjacent Raman amplifier module.

17. The Raman amplifier method of claim 16 , wherein a wavelength of the transmitter is outside a range of wavelengths associated with the one or more Raman pumps, outside a range of wavelengths associated with Wavelength Division Multiplexed (WDM) channels, and different from a wavelength associated with an Optical Service Channel (OSC).

18. The Raman amplifier method of claim 16 , wherein the OTDR is configured to operate out-of-service and in-service where the one or more Raman pumps are operational.

Assignees

• Ciena Corp

Inventors

• Archambault Jean-Luc
• Bao Jun
• Sridhar Balakrishnan

Classifications

• H04J14/0227

  Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation · CPC title

• H04Q9/00 Primary

  Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom · CPC title

• H01S3/1312

  by controlling the optical pumping · CPC title

• H01S3/094046

  of a Raman fibre laser · CPC title

• G01M11/3136

  for testing of multiple fibers · CPC title