Characterization of ultra-narrow linewidth lasers for phase-sensitive coherent reflectometry using EOM facilitated heterodyning

摘要： A new scheme of heterodyning facilitated by electro-optic modulator (EOM) is used to characterize the Allan deviation and phase noise of the beat note generated using different pairs of highly coherent lasers. Use of EOM greatly expands optical frequency difference range between the paired lasers suitable for heterodyning. Experimentally demonstrated that sensitivity of optical time-domain reflectometer is mostly determined by the instantaneous linewidth of the probing laser. Observed laser frequency linear drift for all tested lasers was found to be harmless at 1 kHz probing rate. Demonstrated technique can be used to qualify lasers for phase-sensitive optical distributed sensing applications.