Adding channels with PSBT format at 40 Gbit/s in an existing 10 Gbit/s optical network

Until recently, the wavelength-division-multiplexed (WDM) transmission system has reached record capacities and distances due to innovations such as FEC (Forward Error Correction), distributed Raman amplification, new transmission fiber and advanced optical format. Optical-communication systems exclusively employed conventional On-Off Keying signals in either Non-Return-To-Zero (NRZ) or Return-To-Zero (RZ) format. Recently a number of advanced modulation formats have attracted attention. Some of these formats carry information through On-Off-Keying but also modulate the optical phase in order to enhance the robustness of signal to chromatic dispersion, optical filtering and non-linearities. Through extensive sets of simulation results, we showed that it is possible to replace a channel with higher bit-rate on existing DPSK or OOK at 10Gbit/s transmission link. Duobinary formats are ideal candidates to do it and are known for their low spectral range and high tolerance to residual chromatic dispersion. These particularities make them very attractive for both high bit rates and high distance-transmissions. Today, Phase Shaped Binary Transmission (PSBT) is considered as being the promising format for the deployment of 40Gbit/s technology on existing links at 10Gbit/s WDM long haul transmissions.     

利用魏格纳分布对光脉冲在40Gbit/s系统中传输特性的研究

使用时频域联合分析的方法对光脉冲在40Gbit/s光纤通信系统中的传输特性进行了分析。在进行时频域联合分析时,利用著名的魏格纳分布。利用魏格纳分布的时频域联合分析是在时频交合平面上对光脉冲进行分析,即光脉冲在此平面上同时是时间和频率的二维函数。具体实例证明,这个独有的属性使得基于魏格纳分布的时频域联合分析法能够提供信号的各个频谱分量的时域分布,即提供了各个频谱分量的瞬时特性。为此,利用魏格纳分布的时频联合分析法可以较为全面地描述光脉冲的信息,进而较为全面地描述光纤通信系统的性能。     

Optical millimeter-wave generation and transmission system for 1.25 Gbit/s downstream link using a gain switched laser

In this paper, we propose a novel and cost effective system for optical millimeter-wave (mm-wave) generation and transmission of downstream data based on a gain switched laser (GSL). The GSL produces an optical comb spectrum that can be appropriately filtered to generate two optical sidebands spaced by more than 4 times the repetition rate of the GSL. These sidebands are modulated by baseband data and then transmitted via optical fiber to the remote antenna unit (RAU). At the RAU, the two sidebands are heterodyned using a photodetector to generate the electrical modulated mm-wave signal, before demodulation using self mixing. We demonstrate the distribution of 1.25 Gbit/s data OOK modulated onto a 60 GHz carrier, similar to that used in the IEEE 802.15.3c draft standard, over fiber lengths up to 62 km.