Randomly spaced chirped grating-based random fiber laser

A random fiber laser is demonstrated using a randomly spaced chirped-fiber Bragg grating (CFBG) array, which was fabricated along a 1-m-long erbium-doped fiber using a UV laser with a random separation ranging from 30 to 100 mm. Random distributed feedback is effectively realized through reflection of the CFBGs and further enhanced by changing chirp directions of the gratings. When pumped with a 980-nm laser diode, laser with multi-wavelength output was achieved with a pump threshold of 15 mW. Laser performance was studied as a function of pump power and time.