RCLED Optimization and Nonlinearity Compensation in a Polymer Optical Fiber DMT System

Abstract

Abstract:In polymer optical fiber (POF) systems, the nonlinear transfer function of the resonant cavity light emitting diode (RCLED) drastically degrades the communication performance. After investigating the characteristics of the RCLED nonlinear behavior, an improved digital look-up-table (LUT) pre-distorter, based on an adaptive iterative algorithm, is proposed. Additionally, the system parameters, including the bias current, the average electrical power, the LUT size and the step factor are also jointly optimized to achieve a trade-off between the system linearity, reliability and the computational complexity. With the proposed methodology, both the operating point and efficiency of RCLED are enhanced. Moreover, in the practical 50 m POF communication system with the discrete multi-tone (DMT) modulation, the bit error rate performance is improved by over 12 dB when RCLED is operating in the nonlinear region. Therefore, the proposed pre-distorter can both resist the nonlinearity and improve the operating point of RCLED.

A new modulation scheme in polymer optical fiber communications using Jacket matrix spreading

“…There are N sub-carriers for a DMT symbol; the bit stream is mapped onto X u = A u +jB u (u = 1; ; N 1) based on the Quadrature Amplitude Modulation (QAM) constellation, and then the DMT signals are illustrated as follows [4][5][6][7]:…”

“…Most recent works have already shown experimentally that adopting spectrally e cient modulation techniques within Intensity Modulation with Direct Detection (IM/DD) structures could overcome the bandwidth limitation of the SI-POF and extend the system capacity [3]. With the low-cost consideration, Discrete Multi-Tone (DMT) modulation [4][5][6][7], demonstrating strong ability of anti-multipath and anti-fading, is regarded to be future-proof solutions for maximizing the transmission rate in SI-POF system [8,9]. Therefore, employing the DMT with bit-loading techniques makes the Gigabit transmission over SI-POF available.…”

Deep clipping noise mitigation using ISTA with the specified observations for LED‐based DCO‐OFDM system

“…Direct current (DC) biased O-OFDM [5] is one of the main approaches. However, it suffers from non-linear distortion due to both the high peak-toaverage power ratio (PAPR) of transmitting signal and the limited linear dynamic range of LED, which will lead more signal distortions thus drastically deteriorate the overall system performance [6,7]. Therefore, the LED non-linearity becomes even more critical for DCO-OFDM system and should be mitigated accordingly.…”