Single-pass parametric generator made of DFB diodes, specialty-fiber amplifier, and periodically-poled lithium niobate

A compact pulsed mid-IR source with 10-ns pulsewidth, few hundred-microjoule energy, and repetition rate adjustable from 10 through 500 kHz is reported. In order to reach up to 30-% efficiency of down-conversion from 1064 nm to 1500/3500 nm, a 1064-nm narrow-line master oscillator is followed by a two-stage fiber amplifier. In turn, this amplifier is spliced with a large-mode-area photonic crystal fiber to ensure high quality of the beam that pumps a 5-mm thick periodically poled MgO-doped lithium niobate. The spectrum of the device replicates that of a cw 1500-nm seed laser.