Application of Magneto Optical Switch in Wind LiDAR

Basic principles of magneto-optical switch:

The magneto-optical switch is an optical switch that utilizes the Faraday magneto-optical effect. It changes the effect of the magneto-optical crystal on the polarization plane of the incident polarized light by changing the external magnetic field, thereby achieving the effect of optical path switching.

Compared with traditional mechanical optical switches, magneto-optical switches have obvious advantages. The switching speed of the magneto-optical switch reaches μs level and has the following advantages: low polarization sensitivity, no moving parts, small insertion loss, fast response speed, high degree of integration, small crosstalk, small size, etc.

It can meet the requirements of strong anti-interference ability, low driving voltage, high stability, simple and reliable circuit design, and long-term continuous operation.

Application in Wind LiDAR:

The laser emitted by the laser light source system is coupled to the optical antenna by an optical fiber. The radar is equipped with four light-emitting lenses, with an angle of 30° horizontally and an angle of 25° vertically. The four laser beams are switched at a frequency of 50HZ.

The lens in the optical antenna is focused to a fixed distance, where the energy is most concentrated and scatters with the aerosol at that point. The scattered returned light is coupled back into the optical fiber through the lens.

It is mixed with the local oscillator light generated by the laser light source system in the coupler, and then the optical signal is converted into an electrical signal by the photoelectric conversion module and amplified.

The data acquisition system collects electrical signals and performs spectrum processing, and then the data processing system calculates the spectrum to obtain the wind speed information of the single channel.