Multiplexing Self-Mixing Interference in Fiber Ring Lasers

A means of obtaining independent multiplexing self-mixing interference (SMI) in fiber ring lasers (FRLs) for measurement or sensing is presented. A demultiplex/multiplex arrayed waveguide grating (AWG) is adopted for multiplexing. The expression of output powers without and with optical feedback in FRL is analyzed. The gain competition and the intensity alternation among different channels are discussed when optical feedback is introduced. The experimental results show that the SMI signal in one channel has little influence on other channels. Therefore, multichannel sensing or measurement will be realized at the same time without disturbance.