Simple all-optical FFT scheme enabling Tbit/s real-time signal processing

Abstract

A practical scheme to perform the fast Fourier transform in the optical domain is introduced. Optical real-time FFT signal processing is performed at speeds far beyond the limits of electronic digital processing, and with negligible energy consumption. To illustrate the power of the method we demonstrate an optical 400 Gbit/s OFDM receiver. It performs an optical real-time FFT on the consolidated OFDM data stream, thereby demultiplexing the signal into lower bit rate subcarrier tributaries, which can then be processed electronically.

Silicon-based photonic ring resonators for optical OFDM demultiplexing

“…In this section, we propose a fully all-optical OFDM demultiplexing scheme which is based on the cascade of several ring resonators using an architecture similar to that presented in [4] for optical FFT implementation.…”

“…3 we show the schematic of the simulation set up used for the transmission of 160-Gb/s OFDM signals. The OFDM transmitter is similar to that shown in [4]. It employs a 40-GHz spaced optical frequency comb to generate 4 OFDM subcarriers (see Fig.…”

“…To deal with bit rates beyond 100 Gb/s, the FFT must be done at the optical domain, thus allowing the electrical speed requirements to be relaxed and the energy consumption reduced. In the literature, some all-optical FFT implementations have been proposed [3][4]. Such all-optical FFT circuits can be applied to demultiplex the optical OFDM channel and are usually comprised of several stages, each of which contains appropriate temporal delays and phase shifts.…”

All-Optical Signal Processing for High Spectral Efficiency (SE) Optical Communication

“…Recently, all-optical FFT scheme enabling Tbit/s real-time signal processing has been proposed [9]. The method based on only passive optical components realizes the highest speed signal processing without the power consumption where electronics cannot be used.…”

“…The method based on only passive optical components realizes the highest speed signal processing without the power consumption where electronics cannot be used. This approach combines the advantages of the electronic high precision processing of the low bit rates and the optical processing of high bit rates [9]. However, OFDM is characterized by the inter-symbol-interference (ISI) and inter-carrierinterference (ICI) caused by a large number of subcarriers [4].…”