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Optical receiver using silicon APD for space applications

Laser altimetry and deep space communications are two typical applications requiring very low noise optical receivers in order to achieve detection of weak and short optical pulse. Avalanche photodiode is the detector of choice for its high quantum efficiency, compact size, reduced electronics complexity and its ability to operate in a radiation-hard environment. Optimal operating condition in terms of APD gain and temperature is the key to maximize the signal to noise ratio. This paper describes the model and the measured performance of a hybrid optical receiver using a TE cooled Silicon Avalanche Photodiode. Receiver performance in terms of responsivity and NEP will be presented as a function of temperature, signal power and APD Gain. A brief discussion of radiation impact on noise is also presented. A NEP of only 5fW/sqrt(Hz) has been obtained with a bandwidth of 200MHz in linear mode at a wavelength of 1060nm.