Programmable gain clamped and flattened-spectrum high power erbium-doped fiber amplifier
First Claim
1. A programmable gain-clamped flattened-spectrum erbium-doped fiber amplifier comprising:
- a filter means for flattening the gain of an output signal versus an input signal with respect to wavelength;
an interface means for selecting a desired overall gain;
means for measuring the signal strength of the input signal and providing an input measurement based thereon;
means for measuring the signal strength of the output signal and providing an output measurement based thereon;
a controller means for controlling the bias currents of an input pump and an output pump to maintain the selected desired overall gain based on the input measurement and the output measurement.
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Accused Products
Abstract
A fiber amplifier using a single, general-purpose, fixed, gain-flattening filter to provide a flattened response with respect to wavelength for the C-Band. A feedback loop comprises a micro controller that maintains the amplifier in a selected gain-clamped mode. This facilitates use in a variety of networks that may use a variety of different types and brands of equipment. The micro controller varies the bias current of a first laser pump and a second laser pump in response to input received from an input monitor and an output monitor so that the overall selected composite power gain is maintained.
An iterative process determines the attenuation function of the filter based on amplifier parameters for each of the selectable gain modes. The determined attenuation functions corresponding to each of the modes are mathematically averaged; the result being the overall attenuation function of the filter. An interface allows selection of desired gain modes.
11 Citations
12 Claims
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1. A programmable gain-clamped flattened-spectrum erbium-doped fiber amplifier comprising:
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a filter means for flattening the gain of an output signal versus an input signal with respect to wavelength;
an interface means for selecting a desired overall gain;
means for measuring the signal strength of the input signal and providing an input measurement based thereon;
means for measuring the signal strength of the output signal and providing an output measurement based thereon;
a controller means for controlling the bias currents of an input pump and an output pump to maintain the selected desired overall gain based on the input measurement and the output measurement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for determining a best-fit overall attenuation function of a gain-flattening filter for use in a gain-clamped flattened-spectrum fiber amplifier comprising:
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determining for each of a plurality of gain mode values an attenuation function that flattens the inherent transfer function characteristics of the fiber amplifier; and
averaging the plurality of attenuation functions corresponding to the plurality of gain mode values using a mathematical process.
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10. A method for operating a gain-clamped flattened-spectrum fiber amplifier comprising:
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applying to each of a first laser pump and a second laser pump an operating bias current equal to the threshold current of each respective laser pump;
increasing the operating bias current to the first pump until either a desired overall amplifier gain is achieved or the first pump'"'"'s maximum output is reached; and
increasing the operating bias current to the second pump until the desired overall amplifier gain is achieved or the second pump'"'"'s maximum output is reached, if the desired overall gain was not achieved by increasing the operating bias current to the first pump. - View Dependent Claims (11, 12)
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Specification