Tuning of laser frequency spacing output by lasers via fiber ring filter banks

This study investigates the influence of the fiber ring filters on the laser frequencies output by a laser system. The approach involves the integration of fiber rings with varying lengths via a spectrally tunable coupler, culminating in the generation of a comb spectrum characterized by two distinct frequency spacings within the primary ring cavity. Subsequent to this, selective frequency filtering is attained by adjusting the central frequency of the fiber tunable filter. Through simulation verification, the laser system is capable of outputting single-frequency laser light at 10.1 nm spacings within the tuning range of 1529.93-1560.22 nm and at 6.4 nm spacings within the range of 1530.95-1562.96 nm.