HETERODYNE OPTICAL PHASE-LOCKED LOOP BY CONFOCAL FABRY-PEROT CAVITY COUPLED ALGAAS LASERS

Two external confocal Fabry-Perot cavity coupled 0.83 μm AlGaAs lasers have been phaselocked to one another by a heterodyne optical phaselocked loop. The phase error under phase locking conditions was measured using the square root of the Allan variance. The result confirmed that the heterodyne signal was a full replica of the spectrum of the reference RF signal within the loop bandwidth. The estimated phase error variance ≈ was 0.02 rad2, i.e., ≈ 8.1°. © 1990 IEEE