All-optical dynamic gain equalizer
AssigneeTropic Networks Inc.
InventorEddie Kai Ho Ng
Life of this patent
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Abstract
The present invention provides an all-optical dynamic gain equalizer of an open-loop design using nonlinear optical materials for equalizing channel power without the need of complex electronics and close-loop control, and provides pulse reshaping and in some embodiments noise reduction at no extra cost. The invention achieves restoration of spectral power uniformity by employing nonlinear optical limiters with desirable power transfer function curves to each of the optical signals to be equalized. The invention provides the highly desirable functions of dynamic gain equalization, and optical pulse reshaping. Some embodiments constructed according to the invention provide signal dynamic range control by biasing the nonlinear optical limiter with a biasing optical signal.
Claims23
An apparatus for equalizing channel powers of a multichannel optical signal comprising:
- an optical demultiplexer for demultiplexing the multichannel optical signal into a plurality of single channel optical signals,
- for each single channel optical signal a respective nonlinear optical limiter which is adapted to limit the single channel optical signal to produce a limited single channel optical signal;
- and
- an optical multiplexer for multiplexing the limited single channel optical signals to produce an equalized multichannel optical signal, the apparatus further comprising:
- for each single channel optical signal a respective bias optical signal source providing to the nonlinear optical limiter a respective bias optical signal of a wavelength different from each of the single channel optical signals, each bias optical signal having a power, each limited single channel optical signal having a power which has a dynamic range;
- wherein the power of each bias optical signal controls the dynamic range of the power of the respective limited single channel optical signal produced by the respective nonlinear optical limiter.
A method of equalizing channel powers of a multichannel optical signal including:
- demultiplexing the multichannel optical signal into a plurality of single channel optical signals,
- for each single channel optical signal, producing a limited single channel optical signal using a respective nonlinear optical limiter which is adapted to limit the single channel optical signal;
- and
- multiplexing the limited single channel optical signals to produce an equalized multichannel optical signal, the method further comprising:
- for each single channel optical signal, providing to the respective nonlinear optical limiter a respective bias optical signal of a wavelength different from each of the single channel optical signals, each bias optical signal having a power, each limited single channel optical signal having a power which has a dynamic range;
- and
- controlling the power of each bias optical signal to control the dynamic range of the power of the respective limited single channel optical signal.
Dependencies are inferred from the claim text.