Yang Dong, Kumar Shiva
Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON, L8S4K1, Canada.
Opt Express. 2009 Sep 28;17(20):17214-26. doi: 10.1364/OE.17.017214.
An optical orthogonal frequency division multiplexing (OFDM) scheme with Fourier transform in optical domain using time lenses both at the transmitter and at the receiver is analyzed. The comparison of performance between this scheme with the optical OFDM scheme that utilizes fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) in electrical domain is made. The nonlinear effects induced by Mach-Zehnder modulator (MZM) as well as by the fiber are investigated for both schemes. Results show that the coherent OFDM using time lenses has almost the same performance as that using FFT when the electrical driving message signal voltages are low so that MZM operates in the linear region. The nonlinearity of MZM deteriorates the conventional coherent OFDM based on FFT when the power of electrical driving signal increases significantly, but only has negligible impairment on the coherent OFDM using time lenses. Details of the time lens set up are provided and a novel scheme to implement the time lens without requiring the quadratic dependence of the driving voltage is presented.
分析了一种在发射端和接收端均使用时间透镜在光域中进行傅里叶变换的光正交频分复用（OFDM）方案。将该方案与在电域中利用快速傅里叶变换（FFT）和快速傅里叶逆变换（IFFT）的光OFDM方案的性能进行了比较。研究了马赫-曾德尔调制器（MZM）以及光纤对两种方案所引起的非线性效应。结果表明，当电驱动消息信号电压较低，使得MZM工作在线性区域时，使用时间透镜的相干OFDM与使用FFT的相干OFDM具有几乎相同的性能。当电驱动信号的功率显著增加时，MZM的非线性会使基于FFT的传统相干OFDM性能恶化，但对使用时间透镜的相干OFDM仅有可忽略不计的损害。给出了时间透镜设置的细节，并提出了一种无需驱动电压二次依赖性即可实现时间透镜的新颖方案。
