Method and apparatus for amplified spontaneous emission corrected automatic signal power control of an optical amplifier
AssigneeBTI Photonic Systems Inc.
InventorsLijie Qiao, Paul J. Vella
Life of this patent
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Abstract
An optical amplifier system and controller and a method for automatically controlling the usable signal power of an optical amplifier are provided. The method differentiates between the total optical power that includes the amplified spontaneous emission (ASE), and the useful amplified optical signal power at the output of the amplifier. The optical amplifier system comprises an optical amplifier, a first and a second photodetector operable to measure the power of the input and output signals of the optical amplifier and an amplification controller with a control input. The amplification controller is operable to compensate for the ASE power when operating in automatic signal power control mode.
Claims22
A method comprising:
- measuring power of an input optical signal;
- determining a target usable signal power;
- amplifying the input optical signal to produce an amplified optical signal comprising an amplified input optical signal and amplified spontaneous emission (ASE);
- determining an estimate of the ASE power in the amplified optical signal as a non-linear function of gain;
- and
- controlling the amplifying such that the amplified input optical signal has a power substantially equal to the target usable signal power.
An optical amplifier system with an optical input, an optical output and a control input, comprising:
- an optical amplifier in a signal path between the optical input and the optical output, operable to amplify an input optical signal to produce an amplified optical signal comprising an amplified input optical signal and amplified spontaneous emission (ASE);
- a first photodetector operable to measure power of the input optical signal at the optical input;
- a second photodetector operable to measure power of the amplified optical signal at the optical output;
- an amplification controller functionally connected to the optical amplifier, the control input and the first and second photodetectors, operable to:
- determine a target usable signal power;
- determine an estimate of ASE power in the amplified optical signal as a non-linear function of gain of the optical amplifier;
- and
- control the optical amplifier such that the amplified input optical signal has a power substantially equal to the target usable signal power.
A method for controlling an optical amplifier comprising:
- determining target usable signal power;
- estimating ASE power in an amplified optical signal comprising an amplified input optical signal and ASE as a non-linear function of an input optical signal power and the target usable signal power;
- and
- controlling at least one control signal such that the amplified input optical signal has a power substantially equal to the target usable signal power.
A controller comprising:
- a first input operable to receive a measurement of power of an input optical signal of at least one optical amplifier operable to amplify the input optical signal to produce an amplified optical signal comprising an amplified input optical signal and amplified spontaneous emission (ASE);
- a second input operable to receive a measurement of power of the amplified optical signal of the at least one optical amplifier;
- control logic operable to:
- determine a target usable signal power;
- determine an estimate of ASE power in the amplified optical signal as a non-linear function of gain of the at least one optical amplifier;
- and
- provide at least one control signal operable to adjust the gain of the at least one optical amplifier such that the amplified input optical signal has a power substantially equal to the target usable signal power;
- and
- at least one control signal output operable to output the at least one control signal.
Dependencies are inferred from the claim text.