Erbium-doped fiber laser with distributed Rayleigh output mirror

An erbium-doped fiber laser based on random distributed feedback through Rayleigh scattering in a long-distance (5–30 km) single-mode fiber (SMF) is demonstrated for the first time. Under the pump of a 1480 nm laser diode, typical random laser radiation is achieved with an obvious threshold behavior as a function of pump power. Thanks to the fiber Bragg grating (FBG)-based half-opened cavity design and the efficient gain from the pumped erbium-doped fiber, a low threshold power of 10 mW is achieved, which is approximately two orders lower in magnitude than that of previously reported conventional random fiber lasers amplified through distributed Raman effects. Dual-wavelength lasing operation is also achieved by using two FBGs with different reflection wavelengths to collaborate with the distributed Rayleigh output mirror.