Spectrum-adjustable random lasing in single-mode fiber controlled by a FBG

•Random lasing is adjustable by changing bi-directional FBG feedback.•Hybrid dual-wavelength lasing controlled by FBG and RS, respectively, is achieved.•The FBG defining lasing peak is sensitive to temperature, the other is insensitive.

In this paper, we report realization of a spectrum-adjustable random fiber laser (RFL) though central pumping in a single mode fiber (SMF), wherein a fiber Bragg grating (FBG) is mounted in the middle to control the laser output. By adjusting the feedback of the FBG bi-directionally, random lasing with adjustable spectra is realized. A unique hybrid dual-peak lasing spectrum with one peak regulated by the FBG and the other peak determined by distributed Rayleigh scattering (RS) feedback is achieved. It is also revealed that the FBG defining lasing peak is sensitive to temperature variation while the other peak is insensitive to temperature variation.