Optical orthogonal frequency division multiplexed transmission using all‐optical discrete Fourier transform

Abstract

Orthogonal frequency division multiplexing (OFDM) can provide spectrally efficient communication channels because it can utilize carrier orthogonality and various impairment mitigation methods. An optical OFDM signal can be generated electronically to multiplex lower-rate carriers. In recent advancements, OFDM signals are also shown to be generated and demultiplexed by all-optical discrete Fourier transform (DFT), overcoming the speed limit of electronics for >Tbps capacity. High-performance DFT devices, such as arrayed waveguide grating (AWG) or planar lightwave circuit (PLC), are critically required to obtain strong orthogonality for scalable all-optical OFDM (AO-OFDM) system implementations. Advanced techniques such as coherent modulation and detection with digital impairment mitigation are also important for long-reach AO-OFDM transmissions. More recently, optical superchannel schemes have been introduced utilizing coherent detection for multi-Tbps AO-OFDM transmissions. This paper reviews the device and system aspects for the AO-OFDM technology, including a generalized theoretical model to provide an indepth understanding.