UV electro-optic frequency comb hybrid fiber/bulk laser system for molecular wind lidar

This work deals with a 343 nm UV laser based on the frequency tripling of a 1030 nm hybrid fiber/bulk MOPA amplifier. The seed laser source is designed to suit the molecular wind lidar application: 25 ns pulses at 40 kHz repetition rate, spectrally shaped as a frequency-comb matched to the two-waves interferometer used as lidar receiver. The signal is amplified in single-mode and LMA fibers up to a peak power of 15 kW limited by stimulated Brillouin scattering. Then, the signal is amplified in an Yb:YAG free-space amplifier to reach 36 kW peak power. Afterward, the fundamental frequency comb is converted in the UV by frequency tripling using LBO crystals with a conversion efficiency of 26%, resulting in an average power of 9.2 W (230 µJ per pulse at a repetition frequency of 40 kHz). The effect of the nonlinear conversion on the comb and its compatibility with the lidar receiver is studied.