REAM intensity modulator-enabled 10Gb/s colorless upstream transmission of real-time optical OFDM signals in a single-fiber-based bidirectional PON architecture

Reflective electro-absorption modulation-intensity modulators (REAM-IMs) are utilized, for the first time, to experimentally demonstrate colorless ONUs in single-fiber-based, bidirectional, intensity-modulation and direct-detection (IMDD), optical OFDM PONs (OOFDM-PONs) incorporating 25km SSMFs and OLT-side-seeded CW optical signals. The colorlessness of the REAM-IMs is characterized, based on which optimum REAM-IM operating conditions are identified. In the aforementioned PON architecture, 10Gb/s colorless upstream transmissions of end-to-end realtime OOFDM signals are successfully achieved for various wavelengths within the entire C-band. Over such a wavelength window, corresponding minimum received optical powers at the FEC limit vary in a range as small as <0.5dB. In addition, experimental measurements also indicate that Rayleigh backscattering imposes a 2.8dB optical power penalty on the 10Gb/s over 25km upstream OOFDM signal transmission. Furthermore, making use of on-line adaptive bit and power loading, a linear trade-off between aggregated signal line rate and optical power budget is observed, which shows that, for the present PON system, a 10% reduction in signal line rate can improve the optical power budget by 2.6dB. © 2012 Optical Society of America

Optimized Discrete Multitone Communication Over Polymer Optical Fiber

International audienceIn this paper, we propose an overall optimization of discrete multitone (DMT) transmissions over polymer optical fiber (POF). The optimization is carried out from both a theoretical and experimental approach. At first, the parameters of the POF channel characteristics, resonant cavity light emitting diode (RC-LED) dynamic nonlinearity performance and analog-to-digital converter effective number of bits (ENOB), in our digital storage oscilloscope are measured. From the measured results, we investigate the channel capacity of a 50 m step-index POF system. Then the optimal DMT bandwidth is theoretically derived. We also optimize the system with different experimental setups. The optimal cyclic prefix length and RC-LED optimal working current are given. The ENOB can be improved by oversampling and averaging. The optimal oversampling factor is discussed. Furthermore, a joint DMT clipping and subcarrier number optimization is synthetically investigated. Based on the proposed approaches, an optimized DMT gigabit transmission over a real 50 m POF channel employing low-cost components is presented. Finally, a methodology for the practical design of the DMT transmission over POF is concluded

Optimization of Multi-Band DFT-Spread DMT System for Polymer Optical Fiber Communications

Abstract--Recently, polymer optical fiber (POF) became a popular solution for the indoor communications. In this paper, a multi-band discrete-Fourier-transform spread (MB-DFT-S) discrete multi-tone (DMT) system is proposed to study and optimize in terms of POF communications. A joint optimization of used subcarrier number, used bandwidth and multi-band number is investigated. The transmission of MB-DFT-S DMT over 50 m POF link is implemented. Both theoretical and experimental results demonstrate that optimized MB-DFT-S DMT system outperforms the original DMT and DFT-S DMT systems, which means that it is a promising technique for future POF transmission systems

Mode-Dependent Loss and Gain: Statistics and Effect on Mode-Division Multiplexing

In multimode fiber transmission systems, mode-dependent loss and gain (collectively referred to as MDL) pose fundamental performance limitations. In the regime of strong mode coupling, the statistics of MDL (expressed in decibels or log power gain units) can be described by the eigenvalue distribution of zero-trace Gaussian unitary ensemble in the small-MDL region that is expected to be of interest for practical long-haul transmission. Information-theoretic channel capacities of mode-division-multiplexed systems in the presence of MDL are studied, including average and outage capacities, with and without channel state information.Comment: 22 pages, 8 figure