Extensive Comparisons of Optical Fast-OFDM and Conventional Optical OFDM for Local and Access Networks

Abstract

A performance comparison between a recently proposed novel technique known as fast orthogonal frequencydivision multiplexing (FOFDM) and conventional orthogonal frequency-division multiplexing (OFDM) is undertaken over unamplified, intensity-modulated, and direct-detected directly modulated laser-based optical signals. Key transceiver parameters, such as the maximum achievable transmission capacity and the digital-to-analog/analog-to-digital converter (DAC/ADC) effects are explored thoroughly. It is shown that, similarly to conventional OFDM, the least complex and bandwidth efficient FOFDM can support up to ∼20 Gb/s over 500 m worst-case multimode fiber (MMF) links having 3 dB effective bandwidths of ∼200 MHz × km. For compensation of the DAC/ADC roll-off, a power-loading (PL) algorithm is adopted, leading to an FOFDM system improvement of ∼4 dB. FOFDM and conventional OFDM give similar optimum DAC/ADC parameters over 500 m worst-case MMF, while over 50 km single-mode fiber a maximum deviation of only ∼1 dB in clipping ratio is observed due to the imperfect chromatic dispersion compensation caused by one-tap equalizers.

Real-time machine learning based fiber-induced nonlinearity compensation in energy-efficient coherent optical networks

“…This is the worlds' first implementation of machine learning in an FPGA board for compensation of nonlinearities in optical networks. We believe our technique can be also valuable for other modulation techniques such as fast optical orthogonal frequency division multiplexing [15][16][17].…”

Chip-based Brillouin processing for carrier recovery in self-coherent optical communications

“…32-QAM−128-QAM), requiring more complex DSP and sophisticated narrower linewidth LOs (<100 kHz) compared to common distributed feedback lasers (>1 MHz), our technique may relax requirements on very-high-order QAM signaling. Our technique is also transparent to higher spectral-efficient modulation formats (Fast-OFDM) [44] and non-orthogonal signal modulation techniques [45]. It should be noted that while the required SBS gain of benchmark fiberbased SBS-self-coherent systems is limited by the modulation format order, being less attractive for higher-order QAM signals compared to homodyne schemes, here, the large SBS gain (52 dB) provided by a chalcogenide chip [23] could potentially support up to 64-QAM [1] and above.…”

Multi-User Visible Light Communications: State-of-the-Art and Future Directions

“…Later, optical OFDM [23] owing to its appealing performance over the dispersive communication channels and low implementation complexity was proposed. Since the modulating waveform has to be real-valued and nonnegative in intensity modulation and direct detection (IM/DD) systems, several variants of optical OFDM were introduced in the literature [68]- [72]. Two most popular ones are DC-biased optical OFDM (DCO-OFDM), and asymmetrically clipped OFDM (ACO-OFDM).…”