2.05-m all-fiber laser source designed for CO₂ and wind coherent lidar measurement

This work reports on an all-fiber pulsed laser source for simultaneous remote sensing of CO2 concentration and wind velocity in the 2.05 mu m region. The source is based on a polarization-maintaining master oscillator power amplifier (MOPA) architecture. Two narrow-linewidth master oscillators for ON-line/OFF-line CO2 differential absorption lidar operation alternately seed a four-stage amplifier chain at a fast switching rate up to 20 kHz. The MOPA architecture delivers laser pulses of 120 mu J energy, 200 ns duration (600 W peak power) at 20 kHz pulse repetition rate (2.4Waverage power). The output linewidth is lower than 5 MHz, close to the pulse Fourier transform limit, and the beam quality factor is M-2 = 1.12. The source also provides a pre-amplified 20 mWlocal oscillator with a relative intensity noise of -160 dB/Hz that ensures optimal performance for future coherent detection. (C) 2021 Optical Society of America