Coherent Optical DFT-Spread OFDM

TL;DR

This paper explores the application of DFT-spread OFDM in high-speed fiber optic communications, highlighting its advantages like low PAPR and improved BER over traditional optical OFDM systems.

Contribution

It demonstrates the effectiveness of optical DFT-spread OFDM with PDM and MMSE equalization, showing performance benefits over conventional amplitude-clipped OFDM.

Findings

Lower peak-to-average power ratio (PAPR) compared to amplitude clipping

Better bit error rate (BER) performance

Effective use of PDM and MMSE equalizer in optical DFT-spread OFDM

Abstract

We consider application of the discrete Fourier transform-spread orthogonal frequency-division multiplexing (DFT-spread OFDM) technique to high-speed fiber optic communications. The DFT-spread OFDM is a form of single-carrier technique that possesses almost all advantages of the multicarrier OFDM technique (such as high spectral efficiency, flexible bandwidth allocation, low sampling rate and low-complexity equalization). In particular, we consider the optical DFT-spread OFDM system with polarization division multiplexing (PDM) that employs a tone-by-tone linear minimum mean square error (MMSE) equalizer. We show that such a system offers a much lower peak-to-average power ratio (PAPR) performance as well as better bit error rate (BER) performance compared with the optical OFDM system that employs amplitude clipping.