Time-dependent analysis of a fiber-optic passive-loop resonator.

launched into the coupler at the input port 1 will partially emerge at port 3, from which it is guided along the fiber loop and reaches port 2 and will be partially coupled to the output port 4. The field at port 2 will couple partially to port 4 and partially to port 3, thus continuing to circulate in the loop. The characteristics of this all-fiber ring resonator have been investigated both theoretically and experimentally' 2 in a completely coherent case in which the coherence time t, of the field is implicitly assumed significantly to exceed -r = LIV, where L is the fiber loop length and V = (do3/dw)-l is the group velocity of the propagating mode. More recently, an analysis of the performance characteristics of the resonator in terms of the light-source coherence was carried out3 in which the exciting source was assumed to be an amplitude-stabilized single-mode laser field