A pulsed single-longitudinal-mode fiber laser based on gain control of pulse-injection-locked cavity

We achieve a pulsed fiber laser based on injecting a pulsed-seed into a high power fiber ring cavity consisting of two-stage amplifier chain. Through gain control of the fiber amplifier chain and adjustment of a variable optical coupler in the cavity, locking condition is satisfied which produce mode-hopping free, single-longitudinal-mode optical spectrum with 38 dB optical signal to noise ratio. The noise-free lasing RF spectrum has a 7.0 kHz 3 dB linewidth. The nanosecond lasing pulses are jittering-free with 40 W peak power at 1550 nm wavelength.

► Pulsed injection of fiber ring laser in 50 ns, 40 W peak-power pulses at 1550 nm. ► Single-longitudinal-mode, mode-hopping free and kHz linewidth lasing is achieved. ► Injection locking is achieved by intracavity gain control experimentally. ► The laser has 21 dB higher SNR and 4 times narrower bandwidth than the MOPA method. ► The kHz linewidth, high power pulsed fiber laser can be useful for fiber sensing.