RESUMO
We have developed a high-gain, high-peak-power laser amplifier at an eye-safe 1.55 µm wavelength using an Er,Yb:glass planar waveguide for wind sensing coherent Doppler lidars (CDLs). Our planar waveguide is free from stimulated Brillouin scattering and realizes high gain thanks to its multi-bounce optical-path configuration. A peak power of 5.5 kW with a pulse energy of 3.2 mJ is achieved at the repetition frequency of 4 kHz, which leads to an average power of 12.8 W. The gain is more than 23 dB. The wind sensing at more than 30 km is demonstrated with a CDL using the developed amplifier.
RESUMO
We present a semianalytic pulsed coherent laser radar (CLR) equation for coaxial and apertured systems. It combines the conventional CLR equation, numerical Fresnel integration (NFI), and nearest Gaussian approximation, using correction factors that correspond to beam truncation. The range dependence of the signal-to-noise ratio obtained by this semianalytic equation was found to agree well with the precise NFI solution for not only the focal range, but also the near-field range. Furthermore, the optimum beam truncation condition depending on the atmospheric refractive index structure constant is shown. The derived equation is useful for precisely predicting the CLR performance simply by its semianalytic expression.
