Dual-polarization multi-band optical OFDM transmission and transceiver limitations for up to 500 Gb/s uncompensated long-haul links

Abstract

A number of critical issues for dual-polarization single-and multi-band optical orthogonal-frequency division multiplexing (DP-SB/MB-OFDM) signals are analyzed in dispersion compensation fiber (DCF)-free long-haul links. For the first time, different DP crosstalk removal techniques are compared, the maximum transmission-reach is investigated, and the impact of subcarrier number and high-level modulation formats are explored thoroughly. It is shown, for a bit-error-rate (BER) of 10 −3 , 2000 km of quaternary phase-shift keying (QPSK) DP-MB-OFDM transmission is feasible. At high launched optical powers (LOP), maximum-likelihood decoding can extend the LOP of 40 Gb/s QPSK DP-SB-OFDM at 2000 km by 1.5 dB compared to zero-forcing. For a 100 Gb/s DP-MB-OFDM system, a high number of subcarriers contribute to improved BER but at the cost of digital signal processing computational complexity, whilst by adapting the cyclic prefix length the BER can be improved for a low number of subcarriers. In addition, when 16-quadrature amplitude modulation (16QAM) is employed the digital-toanalogue/analogue-to-digital converter (DAC/ADC) bandwidth is relaxed with a degraded BER; while the 'circular' 8QAM is slightly superior to its 'rectangular' form. Finally, the transmission of wavelength-division multiplexing DP-MB-OFDM and single-carrier DP-QPSK is experimentally compared for up to 500 Gb/s showing great potential and similar performance at 1000 km DCF-free G.652 line.

Reduced-Complexity Artificial Neural Network Equalization for Ultra-High-Spectral-Efficient Optical Fast-OFDM Signals

“…The transmission-reach of the developed system was set at 640 km (8 spans with a fiber-link length of 80 km). The length of CP was set at 25% to ensure effective elimination of inter-symbol interference [28,29]. At the receiver-end of the simulation set-up a single low pass filter (LPF) unit The designed ANN for NLE operation in optical Fast-OFDM performs Riedmiller-resilient based back-propagation (RP) [24][25][26][27] for the purpose of updating the weights.…”

“…The transmission-reach of the developed system was set at 640 km (8 spans with a fiber-link length of 80 km). The length of CP was set at 25% to ensure effective elimination of inter-symbol interference [28,29]. At the receiver-end of the simulation set-up a single low pass filter (LPF) unit was employed having 3 dB bandwidth of approximately 3 GHz.…”

Performance analysis of AO‐OFDM‐CDMA with advanced 2D‐hybrid coding for amplifier‐free LR‐PONs

“…In Fig. 7, we show simulated results over SSMF by adopting the well known non-linear Schrödinger equation in the split-step Fourier method [22,23] including both linear (chromatic dispersion, polarisation-mode dispersion) and non-linear effects (n2 Kerr-induced non-linearity) for IM/DD 16-QAM AO-OFDM-CDMA and a conventional multi-channel 16-QAM optical OFDM system using coherent technology (CO-OFDM with in-phase and quadrature (IQ) modulation at transmitter and homodyne coherent receiver) with procedure identical to [23]. In summary, the WDM-CO-OFDM provides 10 GHz spacing between nine channels with 40 Gb/s signal capacity (25 GS/s sampling rate) per-channel using 16-QAM.…”

Compensation of filter cascading effects and non‐linearities in flexible multi‐carrier‐based optical networks using a complex‐kernel‐based support vector machine

“…The DP‐MB‐OFDM‐based super‐channels consist of eight OFDM sub‐bands per polarisation modulated by differential quaternary phase‐shift keying (DQPSK) or 8‐, 16‐, 32‐QAM with a digital transceiver design as shown in Fig. 1 b , which is identical to [17]. For PC‐SC, the transceiver design is similar to [14, 15].…”

“…Phase noise and frequency offset have been considered in the simulation model. The digital‐to‐analogue converter/analogue‐to‐digital converter (ADC) clipping ratio and quantisation have been taken into account and set to 13dB and 10 bits, respectively [17]. The generated pseudo‐random binary sequence counted 2 19 − 1 bits which were sent over 1000 symbols for 256 subcarriers per sub‐band (168 were the data subcarriers and the rest 88 zero subcarriers).…”