In optical sensing applications, the laser sources are strongly constrained by the sensing system requirements. In the case of coherent LIDARs, that measure wind speed thanks to the Doppler shift (by means of a coherent detection), highly coherent high power pulsed lasers with good output beam quality are necessary to guarantee a proper measurement over long distances. The pulsed emission ensures the spatial resolution along the line of sight whereas the high coherence accounts for the wind speed resolution (measured in the frequency domain). Thus, the challenge when designing laser sources for such instruments resides in the difficulty of improving the output power while not altering the other characteristics.
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