Coherent optical OFDM transmitter design employing predistortion

Abstract

In this letter, we analyze the transmitter design for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) employing predistortion. Digital clipping and digital predistortion processes are introduced to the radio frequency OFDM transmitter to compensate the nonlinearity effect introduced by the optical in-phase/quadrature modulator.We first provide a detailed description of signal processing involved in digital clipping and predistortion.We then carry out a numerical simulation to identify the performance dependence on clipping ratio, digital-to-analog converter (DAC) resolution, and modulation index.We find that for quadrature phase-shift keying modulation, 4-bit DAC resolu..