Phase Noise Effects on High Spectral Efficiency Coherent Optical OFDM Transmission
Phase Noise Effects on High Spectral Efficiency Coherent Optical OFDM Transmission
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DOI：
10.1109/jlt.2008.919368
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发表时间：
2008-05
影响因子：
4.7
通讯作者：
X. Yi;W. Shieh;Yiran Ma
中科院分区：
文献类型：
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作者：
X. Yi;W. Shieh;Yiran Ma
采用数字信号处理的相干光正交频分复用（CO-OFDM）传输有三个主要优点。首先，通过数字相位估计实现相干检测，不需要光锁相环。其次，通过快速傅里叶变换（FFT）和反FFT实现OFDM调制解调。第三，由于不同的正交调幅（QAM）星座是软件定义的，因此可以支持自适应数据速率，而无需对发射器和接收器进行任何硬件更改。然而，众所周知，相干检测、OFDM和QAM都容易受到相位噪声的影响。本文对相位噪声对高频谱效率CO-OFDM传输的影响进行了理论、数值和实验研究。提出了存在相位噪声时的传输模型。通过仿真，给出了具有高阶QAM星座的CO-OFDM系统在有限激光线宽下的误码率下限。在实验中，研究了激光线宽和非线性光纤传输对相位噪声的影响。讨论了基于接收机数字信号处理的光纤非线性抑制方法。
There are three major advantages for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) transmission using digital signal processing. First, coherent detection is realized by digital phase estimation without the need for optical phase-locked loop. Second, OFDM modulation and demodulation are realized by the well-established computation-efficient fast Fourier transform (FFT) and inverse FFT. Third, adaptive data rates can be supported as different quadrature amplitude modulation (QAM) constellations are software-defined, without any hardware change in transmitter and receiver. However, it is well-known that coherent detection, OFDM, and QAM are all susceptible to phase noise. In this paper, theoretical, numerical, and experimental investigations are carried out for phase noise effects on high spectral efficiency CO-OFDM transmission. A transmission model in the presence of phase noise is presented. By using simulation, the bit error rate floors from finite laser linewidth are presented for CO-OFDM systems with high-order QAM constellations. In the experiments, the phase noise effects from both laser linewidth and nonlinear fiber transmission are investigated. The fiber nonlinearity mitigation based on receiver digital signal processing is also discussed.