Compact narrow-width distributed feedback fiber laser

Directly etching an active grating in Er/Yb codoped fiber, a compact asymmetric π phase-shifted fiber laser was fabricated. The designed grating length is only 50 mm, the optimal phase shift position is at 29 mm, and the optimal coupling coefficient value is 150 m－1 . Adopting forward pumped manner by 980 nm LD, when pumped power was of 200 mW, at 1 550.94 nm we have achieved the narrow-band laser output of 10 mW, its width was narrower than 0.05 nm, the threshold was 35 mW, the slope efficiency was 6.06%, total optical conversion efficiency was 5%. The fiber laser has met the practicality of light sources' power in the long-term optical communications system．