Polarization multiplexing-based direct detection wind lidar

Abstract

The invention discloses a polarization multiplexing-based direct detection wind lidar. based on the principle that laser beams having mutually perpendicular polarization states have different transmittance curves when passing a Fabry-Perot interferometer, a continuous laser beam is divided into two branches having the mutually perpendicular polarization states by the polarization multiplexing technique, one branch is used to detect the atmospheric wind field after subjected to pulse modulation, the other branch is used to lock laser frequency, the two branches share the Fabry-Perot interferometer, and the two branches are combined, separated and detected with a polarization-maintaining combiner and a polarization splitter. The use of one Fabry-Perot interferometer allows frequency shift detection and frequency tracking and locking to be simultaneous; compared with the system comprising a multi-channel Fabry-Perot interferometer or multiple Fabry-Perot interferometers, the lidar has lower cost, compacter structure and higher stability.

Description

technical field [0001] The invention relates to the technical field of direct detection Doppler wind measurement laser radar, in particular to a direct detection wind measurement laser radar based on polarization multiplexing. Background technique [0002] Since the 1980s, the direct detection wind lidar technology has gradually matured, and the direct detection lidar technology has emerged in the field of wind detection lidar with its unique advantages (high temporal and spatial resolution, large spatial coverage, and high measurement accuracy, etc.). [0003] Basic research on Doppler direct detection wind lidar based on Fabry-Perot interferometer has been carried out at home and abroad, including system parameter design, simulation and other work. Abroad: Rayleigh-Mie Doppler wind lidar developed by Haute Provence Observatory in France; ALAMOR system jointly developed by Germany, Britain, Norway; GLOW and Groundwinds developed by NASA, NCAR and Michigan Aerospace Corporat...

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Problems solved by technology

[0008] The above three methods have the following disadvantages: in the above method 1), since the Fabry-Perot interferometer needs to be pressurized and decompressed during the adjustment process, this is a slow process, so real-time tracking and locking cannot be carried out; in the above method 2) , because another laser needs to be added as a reference light, and the method of coherent beat frequency is adopted, the structure of the optical path is complex, the requirements for optical devices are strict, the amount of subsequent data processing is large, and the system cost is high; in the above method 3), due to the addition of the third channel method, the system is complicated and the cost is high

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