Nonlinear Distortion in SPAD-Based Optical OFDM Systems

In this paper, an optical orthogonal frequency division multiplexing (OFDM) system based on a single-photon avalanche diode (SPAD) receiver with a nonlinear distortion is presented. In this study, the methods to calculate the output of passive and active quenching SPAD arrays are given. Nonlinear performances of these two SPAD arrays and their effects on bit-error ratio performances of SPAD-based DC-biased optical OFDM and asymmetrically clipped optical OFDM are simulated in the absence of background light. In the simulation, the maximum optical irradiance and the low error area are given as the metrics of the nonlinear distortion. The effects of the nonlinear distortion are discussed for different modulation schemes, symbol rates and spectral efficiencies.