Pulsed measurement based nonlinear characterization of avalanche photodiode for the time error correction of 3D pulsed laser radar

In this research work a distinctive method of nonlinearity error elimination is demonstrated in a high precision pulsed laser radar system. The phenomenon of nonlinearity error arises from high signal dynamics, and has profound impact on high frequency sensors. High precision range sensors have a wide range of applications as machine vision, medical imaging and industrial sensors. Using synchronized pulsed optical signal, pulsed RF technique was extended for characterisation of opto-electronic devices. Large signal model of the avalanche photodiode was developed using pulsed measurement. Earlier measurement approaches of using CW microwave signal encounters thermal problems and lacked the dynamic range of usage. Present method allowed isothermal characterization of the photodiode in its complete practical range. In this approach, the large signal model of the avalanche photodiode was introduced to compensate the signal-dynamic effect in a high precision near range laser radar. Classical methods use mechanical attenuators to compensate the signal dynamic effect. Beside the advantages of low-cost, faster, and straight-forward solution, present principle is generic, and is applicable to practical high frequency sensors in general.