Self-coherent detection for optical OFDM via polarization diversity

An improved self-coherent digital-signal-processing-based optical receiver that utilizes polarization diversity is presented and analyzed. It demonstrates that coherent performance can be approached by employing field reconstruction on differential-phase detection and judicious digital signal processing. Performance is improved compared to known techniques by addressing two shortcomings that characterize self-coherent detection: 1. the phase drift caused during field reconstruction; and 2. the loss of synchronization induced by a zero-intensity sample with undefined phase. These will be met with phase estimation and periodic correction, and with polarization-diversity and a non-linear quantization scheme, respectively. It is demonstrated by means of simulations that the improved receiver allows achieving detection of an optical orthogonal frequency division multiplexing at uncoded bit-error-rate of 3*10-5, with 12 bit non-uniform quantization, over an 18 dB signal-to-noise ratio channel.