Demonstration of a 3 mW threshold Er-doped random fiber laser based on a unique fiber Bragg grating

We demonstrate a novel random laser based on a single fiber Bragg grating. A long fiber Bragg grating fabrication technique allows the insertion of a large number of randomly distributed phase errors in the structure of the grating which induces light localization. By writing such a grating in a polarisation maintaining Er-doped fiber, a random laser is demonstrated by pumping the fiber with 976 and 1480 nm pump lasers. The number of emitted modes is observed to be a function of the length of the grating and of the pump power and single-mode operation is shown to be possible. The random fiber laser shows low-threshold (approximately 3 mW) and measured approximately 0.5 pm emission linewidth at a wavelength of around 1534 nm.