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

Area of Science:

• Fiber laser technology
• Remote sensing instrumentation
• Atmospheric monitoring

Background:

• Accurate measurement of atmospheric gases like carbon dioxide (CO2) and wind velocity is crucial for climate monitoring and weather forecasting.
• Existing remote sensing technologies often face limitations in simultaneous measurement capabilities and system integration.

Purpose of the Study:

• To develop and characterize an all-fiber pulsed laser source for simultaneous remote sensing of CO2 concentration and wind velocity.
• To enable differential absorption lidar (DIAL) applications in the 2.05 µm spectral region.

Main Methods:

• Utilized a polarization-maintaining master oscillator power amplifier (MOPA) architecture.
• Employed two narrow-linewidth master oscillators for ON-line/OFF-line CO2 DIAL operation, alternating at a 20 kHz switching rate.
• Characterized laser pulse energy, duration, peak power, repetition rate, average power, linewidth, and beam quality (M²).

Main Results:

• Achieved laser pulses with 120 µJ energy, 200 ns duration, and 600 W peak power at a 20 kHz repetition rate.
• Delivered 2.4 W average power with an output linewidth < 5 MHz, near the Fourier transform limit.
• Obtained a beam quality factor of M²=1.12 and a local oscillator with relative intensity noise of -160 dB/Hz.

Conclusions:

• The developed all-fiber pulsed laser source is suitable for simultaneous CO2 and wind velocity remote sensing.
• The system's performance characteristics, including high pulse energy and narrow linewidth, are advantageous for lidar applications.
• The integrated local oscillator supports future coherent detection, enhancing measurement precision.