Optical amplifier with a spectral gain monitor using a volume phase grating

A optical signal amplifier system for amplifying a wavelength division multiplexed (WDM) input signal, the amplifier system comprising:

• a first optical coupler configured to receive the WDM input signal and extract a portion thereof;
• an optical amplifier in optical communication with the first optical coupler and configured to amplify the WDM input signal and generate a WDM output signal;
• a second optical coupler in optical communication with the optical amplifier, the second optical coupler configured to extract a portion of the WDM output signal;
• a spectral monitoring unit in optical communication with the first optical coupler and the second optical coupler, the spectral monitoring unit having a volume phase grating and configured to determine the power level in prescribed channels of the extracted input and output WDM signals;
• and
• a controller in electrical communication with the spectral monitoring unit and the optical amplifier, the controller configured to operate the optical amplifier in response to the power levels of the extracted input and output WDM signals.

A method of amplifying an input WDM optical signal with an optical amplifier system having a first and a second optical coupler, a first and a second spectral monitoring unit, an optical amplifier, and a controller, the method comprising the steps of:

• a) extracting a portion of the input WDM optical signal with the first optical coupler;
• b) separating the extracted portion of the input WDM optical signal into prescribed spectral components with the first spectral monitoring unit;
• c) detecting the power level of each of the spectral components of the extracted input WDM optical signal with the first spectral monitoring unit;
• d) amplifying the input WDM optical signal with the optical amplifier in order to generate an output WDM optical signal;
• e) extracting a portion of the output WDM optical signal with the second optical coupler;
• f) separating the extracted portion of the output WDM optical signal into prescribed spectral components with the second spectral monitoring unit;
• g) detecting the power level of each of the spectral components of the extracted output WDM optical signal with the second spectral monitoring unit;
• and
• h) controlling the optical amplifier with the controller in response to the power levels of the spectral components of the extracted input WDM optical signal and the extracted output WDM optical signal.

A method of amplifying an input WDM optical signal with an optical amplifier system having a first and a second optical coupler, a spectral monitoring unit, an optical amplifier and a controller, the method comprising the steps of:

• a) extracting a portion of the input WDM optical signal with the first optical coupler;
• b) amplifying the input WDM optical signal with the optical amplifier in order to generate an output WDM optical signal;
• c) extracting a portion of the output WDM optical signal with the second optical coupler;
• e) separating the extracted portion of the input WDM optical signal and the extracted portion of the output WDM optical signal into respective spectral components with the spectral monitoring unit;
• f) detecting the power level of the spectral components with the spectral monitoring unit;
• and
• g) controlling the amplification of the input WDM optical signal with the optical amplifier and the controller in response to the power level of the spectral components detected by the spectral monitoring unit.

An optical amplifier system for amplifying a wavelength division multiplexed (WDM) optical signal, the system comprising:

• first coupling means for extracting a portion of the input WDM optical signal;
• first monitoring means having a volume phase grating for detecting the power level of spectral components of the extracted input WDM optical signal;
• amplifying means for amplifying the input WDM optical signal and generating an amplified output WDM optical signal;
• second coupling means for extracting a portion of the output WDM optical signal;
• second monitoring means having a volume phase grating for detecting the power level of spectral components of the extracted output WDM optical signal;
• and
• control means for controlling the operation of the amplifying means in response to the power level of the spectral components of the extracted input WDM optical signal and the extracted output WDM optical signal.

A system for amplifying an input optical signal, the system comprising:

• first coupling means for extracting a portion of the power of the input optical signal;
• amplifying means for amplifying the input optical signal;
• second coupling means for extracting a portion of the power of the output optical signal;
• monitoring means having a volume phase grating for separating spectral components of the extracted input and output optical signals and determining the power level of the spectral components;
• and
• control means for controlling the operation of the amplifying means in response to the power level of the spectral components.