Optical OFDM and SiPM Receivers

This paper describes a new silicon photo-multipliers (SiPMs) based optical orthogonal frequency division multiplexing (OFDM) system. A SiPM is arguably the most sensitive optical detector which contains an array of single-photon avalanche diodes (SPADs) and each SPAD is able to detect single photons. However, after each photon is detected, the related SPAD needs several nanoseconds to recover. This causes a nonlinear distortion to the received signal and also introduces inter-symbol interference (ISI) when the transmission data rate is high. In this paper, the impacts of this nonlinearity are studied when optical OFDM is used as the modulation method. A Monte Carlo simulation model is adapted to incorporate OFDM transmission so that the bit error rate (BER) performance of different OFDM schemes is determined. The presented BER results show that the impact of the ISI can be reduced by using frequency domain based post-equalization.