ALL-FIBER COMPOUND RING-RESONATOR WITH A RING FILTER

The new all-fiber compound ring resonator has two rings: a primary one that serves as a resonator, and a secondary one that serves as a filt er. The main contribution of this resonator is to increase the free sp ectral range by choosing the fiber lengths in the compound ring cavity . This resonator with a large free spectral range can be readily used as a doped fiber laser. The optimum resonant conditions of the resonat or are discussed by using an equivalent model and by the transfer matr ix method. The frequency responses of the output and of the circulatin g intensities are given. Mode suppression by the vernier effect is dem onstrated. Comparison with a fiber Fox-Smith resonator is also present ed.