Compact single-mode distributed Bragg reflector fiber laser

A compact single-mode distributed Bragg reflector (DBR) fiber laser with na rrow spectral linewidth is investigated. Firstly, based on our theoretical analysis the single longitudinal mode operation domain is obtained. Then, a single-mode DBR fiber laser of 7.9 cm long with master oscillator power am plifier (MOPA) configuration is designed and constructed to operate in the single-mode domain. The fiber laser is pumped by a semiconductor laser at 9 75.5 nm. The master oscillator operates at 1556.91 nm with a cw output powe r of 1.43 mW for a pump power of 55.35 mW. Its slope efficiency is 2.7% and the spectral linewidth is less than 1.2 MHz (instrument resolution limited ). With the MOPA configuration the laser output power and slope efficiency are increased to 7.8 mW and 16.9%, respectively.