Abstract

Monomode fiber lasers offer the attractions of low threshold, high gain, and compatibility with various monomode fiber devices, such as couplers. The low threshold has enabled cw operation, even on three-level laser transitions, such as the 1.54-μm ⁴I₁₃—⁴I_15/2 transition in Er using a diode laser as the pump. High gain, up to ~30 dB, has been achieved with a cw pump. The long fluorescence lifetime typical of dopants is suited to O-switching, and peak output powers of >10 W have been observed. The broad transition linewidths have allowed significant tuning ranges to be covered, 0.90-0.945 and 1.07-1.135 µm in Nd-doped fiber, and is also suited to short-pulse generation via mode locking. Despite the broad linewidth single-longitudinal-mode operation has been observed from a short fiber with an integral grating reflector. These developments and others on fiber laser research in the U.K. are reported. (Invited paper, 25 min)

© 1988 Optical Society of America