Computerized intelligent optical amplifier for multi-channel optical networks
AssigneeAFC Technologies Inc.
InventorDan D. Yang
Life of this patent
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Abstract
An optical amplifier having a substantially flat response over a multi-channel bandwidth for signals which have different input levels. It utilizes input and output photodetectors for detecting amplitude variations. The gain can be determined by a microprocessor receiving signals derived from the photodetectors, which causes change in the gain of the amplifier. The microprocessor calculates output ASE noise content at different amplifier input levels and subtracts that noise from the total power received by the output detector thereby determining an accurate amplifier gain value. The gain setting offered by the amplifier will then be the same as what is desired by a network management system.
Claims23
An optical signal translation system comprising:
- (a) an optical amplifier, for receiving an input signal and delivering an amplified output signal,
- (b) an input optical signal sampling device,
- (c) an output optical signal sampling device,
- (d) a control circuit for adjusting the gain of the optical amplifier based on a ratio between the sampled output optical signal and the sampled input optical signal relative to a desired gain, and
- (e) a circuit for adjusting the detection range of the input and output sampling devices depending on the amplitude of the input signal, whereby the sampled input and output optical signals along with the ratio therebetween are accurately represented in the control circuit.
An optical signal translation system comprising:
- (a) an optical amplifier for receiving an input signal and delivering an amplified output signal,
- (b) an input optical signal sampling device,
- (c) an output optical signal sampling device,
- (d) a circuit for determining a correct gain of the optical amplifier based on the sampled output optical signal and the sampled input optical signal, wherein the determination includes the subtraction of a predetermined noise characteristic of the amplifier relating to the ASE noise contained in the output optical signal, and
- (e) a control circuit for adjusting the gain of the optical amplifier based on the difference between the correct gain and a desired gain.
A method according to claim 21, wherein step (d) includes:
- determining amplitude of noise in the output signal,
- subtracting the amplitude of noise in the output signal from the amplitude of the output signal to obtain a corrected output signal amplitude, and
- determining a gain error function using the determined gain, noise and signal amplitudes;
- and
- wherein step) (e) includes:
- adjusting the gain of the optical amplifier to correct for the noise amplitude, using the gain error function.
A method of amplifying an optical signal between an input and an output comprising:
- (a) passing the optical signal through an amplifier,
- (b) detecting an optical signal which is input to the optical amplifier,
- (c) detecting an optical signal which is output from the optical amplifier,
- (d) adjusting a range of detection of the input and the output optical signals to varying amplitudes of the input optical signal, whereby the input and output optical signals along with a ratio therebetween are accurately represented in a control circuit;
- and
- (e) adjusting the gain of the optical amplifier based on the ratio between the input and output optical signals using the control circuit.
A method of amplifying an optical signal between an input and an output by a desired gain comprising:
- (a) passing the optical signal through a amplifier,
- (b) detecting an optical signal which is input to the optical amplifier,
- (c) detecting an optical signal which is output from the optical amplifier,
- (d) determining a correct gain, based on the difference between the input optical signal and the output optical signal, wherein the determination includes subtracting a predetermined noise characteristic of the amplifier relating to the ASE noise contained in the output optical signal, and
- (e) adjusting the gain of the optical amplifier based on the difference between the determined correct gain and the desired gain.
A method of controlling the gain of an amplifier to provide a desired signal gain for a first optical signal substantially independent of ASE noise generated within the amplifier, the amplifier comprising an input port for inputting the first optical signal to be amplified, an output port for outputting an amplified optical signal consisting of the ASE noise and the first optical signal amplified, and a pump for providing pump energy, the method comprising the steps of:
- comparing the amplified optical signal with the first optical signal and adjusting the comparison in dependence upon a predetermined noise characteristic of the amplifier relating to the ASE noise contained in the amplified optical signal to obtain a corrected gain;
- and
- adjusting the pump power in dependence upon the corrected gain to obtain the desired signal gain.
Dependencies are inferred from the claim text.