Raman amplifier system and method with integrated optical time domain reflectometer

An optical amplifier module, comprising:

• a Raman amplifier with one or more Raman pumps contained in the optical amplifier module and configured to transmit at Raman wavelengths on a fiber to amplify Wavelength Division Multiplexing (WDM) channels transmitted thereon;
• and
• an optical time domain reflectometer (OTDR) contained in the optical amplifier module and configured to transmit an OTDR signal on the fiber and detect a back-scattered signal based thereon to test the fiber,
• wherein a wavelength of the OTDR signal is one of i) between one or more wavelengths associated with the one or more Raman pumps and one or more wavelengths associated with the WDM channels and ii) greater than the one or more wavelengths associated with the WDM channels, for in-service operation of the OTDR,
• wherein the wavelength of the OTDR signal experiences gain when the Raman amplifier is on, and wherein the OTDR operates with the Raman amplifier on and off to determine gain.

A method implemented by an optical module, comprising:

• amplifying, by an optical amplifier in the optical module, Wavelength Division Multiplexing (WDM) channels transmitted on a fiber;
• transmitting an optical time domain reflectometer (OTDR) signal by an OTDR in the optical module on the fiber, wherein the OTDR is integrated in the optical module with the optical amplifier, wherein the transmitting is performed both with and without the amplifying;
• detecting a back-scattered signal based on the OTDR signal to test the fiber for the transmitting performed both with and without the amplifying;
• and
• determining Raman gain of the optical amplifier based on comparing at least two detected back-scattered signals with and without the amplifying,
• wherein a wavelength of the OTDR signal is one of i) between one or more wavelengths associated with the optical amplifier and one or more wavelengths associated with the WDM channels and ii) greater than the one or more wavelengths associated with the WDM channels, for in-service operation of the OTDR.