A Vernier S-shaped fiber double-loop resonator with double couplers and degenerate two-wave mixing

The use of degenerate two-mixing in a S-shaped fiber double-loop resonator with double couplers to achieve the Vernier operation is proposed. The degenerate two-wave mixing is implemented by inserting a short strand of a photorefractive fiber into the common segment of two fiber loops. With a suitable two-wave mixing gain and a suitable ratio between the free spectral ranges of the two fiber loop resonators, the effective free spectral range can be increased significantly.<
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