A Vernier fiber double-ring resonator with a 3×3 fibercoupler and degenerate two-wave mixing

A theoretical study of a new and simple Vernier fiber ring resonator is presented. The ring resonator consists of two fiber rings constructed from a single-mode 3×3 fiber directional coupler and two single-mode fiber delay lines. Degenerate two-wave mixing is used to achieve the Vernier operation, which significantly increases the free spectral range of the device. In addition, the input beam is also amplified. This device can be used as a wavelength division demultiplexer