Random fiber Bragg grating Raman fiber laser.

We demonstrate for the first time to our knowledge a Raman random fiber laser (RRFL) based on a long random fiber Bragg grating (RFBG-RRFL). Unlike other recently demonstrated random fiber lasers that rely on incoherent Rayleigh scattering feedback, the present scheme uses randomly distributed phase shifts inside a fiber-meter long Bragg grating as a random coherent feedback mechanism. The laser is pumped at 1480 nm and emits a CW signal at 1576 nm. The emission spectrum is dependent on pump intensity and is shown to exhibit single and multi-mode characteristics. The RRFL shows a relatively low threshold (2.2 W) and a ∼430 kHz FWHM linewidth.