An efficient Doppler-shift generator for simulating winds in the middle and upper atmosphere

We report a novel optical Doppler-shift generator that simulates a frequency shift of airglow emission lines introduced by wind in the middle and upper atmosphere for calibrating passive optical interferometers. The generator avoids shortcomings of traditional motor-driven Doppler-shift generators in terms of stability and security while improving accuracy and simplifying assemblies. A simulated wind speed can be determined simultaneously using a light-beat method. The wind error simulated by the generator mainly comes from the light source, which is about 0.63 m/s. An experimental demonstration was conducted by using a calibrated Fabry-Perot interferometer and showed that a root mean square of the measurement uncertainty is 0.91 m/s. The novel Doppler-shift generator was applied to calibrate an Asymmetric Spatial Heterodyne Spectrometer (ASHS) type interferometer successfully. The results demonstrate the feasibility of the new generator.