All-fiber molecular frequency reference at 2 μm based on a versatile laser modulation sideband locking and a hollow-core fiber gas cell

Sensing of atmospheric trace gases is crucial for climate monitoring and to predict global climate changes. The required global coverage and spatial resolution have driven the studies of space-borne differential absorption lidar (DIAL) instruments to remotely monitor atmospheric gases from a satellite to ground. The performance of such instruments is notably determined by the frequency stability and accuracy of a low-power continuous-wave laser that seeds the pulsed laser transmitter. For a CO2 DIAL, this reference laser needs to be stabilized with an adjustable frequency-detuning from the center of the probed molecular transition and the 2.05-μm spectral range is of high interest from a spectroscopic point-of-view [1].