Single Etalon Double-edge Detection of Spectral Shifts Useful for Direct Detection Doppler Lidar

Certain embodiments of the invention may include systems, methods, and apparatus for Doppler light detection and ranging (LIDAR). According to an example embodiment of the invention, a method is provided for measuring atmospheric wind speed. The method includes tuning, in sequence, light output of a laser to a first wavelength and a second wavelength, wherein the first wavelength and the second wavelength are symmetric about a maximum transmission wavelength peak associated with a Fabry-Perot etalon; directing the light output to one or more portions of the atmosphere; receiving backscattered light from the one or more portions of the atmosphere; directing the received backscatter light through the Fabry-Perot etalon; detecting a transmission signal corresponding to light transmitted through the Fabry-Perot etalon; and determining, by at least the transmission signal, atmospheric wind speed at one or more portions of the atmosphere.