Laser Linewidth Compression in Cascading Brillouin Random Fiber Lasers

Abstract

Cascaded Brillouin random fiber lasers (BRFLs) with laser linewidth compression were theoretically and experimentally demonstrated. Thanks to photon-phonon coupled interplay as well as randomly distributed feedback along silica fibers, the coherent time of cascading BRFL radiation is significantly prolonged whilst the phase noise is further suppressed, albeit with a quantum-noiseinduced linewidth narrowing limit. To validate it, the linewidth narrowing ratio in BRFLs, defined as the ratio of the Brillouin pump and its sequent order of Stokes linewidth, was carried out and exhibited a dependence on the Brillouin pump linewidth, which is in good agreement with theoretical predictions. Furthermore, the relative intensity noises of cascading BRFLs were also investigated and discussed.

Brillouin fiber swept laser based on distributed Rayleigh scattering in optical fibers

“…Diverse narrow-linewidth lasers have been demonstrated, including self-injection locking lasers, ultra-short cavity distributed Bragg reflector fiber lasers (DBRs), distributed feedback fiber lasers (DFBs), Brillouin fiber lasers (BFLs) [5] , and so on. In particular, stimulated Brillouin scattering (SBS) gain mechanism exhibits the characteristic of ultra-narrow gain bandwidth of tens of megahertz, benefiting the BFL with extremely narrow linewidth and low phase noise.…”