355 nm Wind Lidar Rayleigh and Mie Return Signal Simulator

The conception and realisation of a prototype 355nm wind lidar return signal simulator capable of simulating the Rayleigh and the Mie return signals is described. The system is based on a commercial dual wavelength 1064nm/532nm diode pumped solid state laser with a monolithic non planar ring Nd:YAG cristal resonator and LBO frequency doubling. This laser is frequency locked to a low power high stability infrared Nd:YAG laser, with frequency offset capability of ± 50 GHz. This low power laser itself is locked to a very high stability Fabry-Perot inerferometer which is located in a thermally stabilised enclosure with a temperature stability of the order of some °mK. Dynamic amplitude shaping is performed with a low voltage electro-optic modulator. Dynamic frequency shaping is performed with four acouso-optic modulators in series, enshuring no beam walk during frequency shifting. The Rayleigh return signal is generated with a pulsed Xe flash lamp spectrally shaped with a grating followed by two air spaced etalons with adapted resolutions, the second, high resolution one, is pressure fine tuned for the exact frequency adjustment with respect to the laser frequency. The combined signal is injected in a 50μm core fiber conveying the signal to the detector test station. The test results are shown.