Using MZIs for Optical PSBT Transmissions: Requirements for Thermal Stabilization

In this paper, we discuss the quantification of Mach‐Zehnder interferometer (MZI) thermal stabilization which is needed in optical phase shaped binary transmission (PSBT) links. Considering the thermo‐optic and thermal expansion effects, we revisit the analytical expression for the thermal drift (GHz/°C) of the MZI center frequency (denoted here by the ‘MZI spectral drift’). An MZI is then used in an experimental transmission system using the optical PSBT format. We study the effect of spectral MZI drift by using a thermally stabilized interferometer and applying a frequency shift to the optical carrier. By using the thermal drift coefficient of the MZI, we find that to ensure low bit error rate fluctuations due to the MZI drift, the thermal stabilization of the device must have an accuracy of 0.5°C.     

光纤传输系统中基于相位预调制的信号整型

利用相位预调制技术解决高速长距离光纤传输系统中面临的接收灵敏度降低和色散容限问题。通过在发射端对非归零(NRZ)的光信号进行比特同步相位预调制,使非归零码在传输过程中得到波形重整,演变为归零(RZ)的波形,从而提高眼图开启度。实验观测了普通非归零码和相位预调制的非归零码在不同相位调制深度和色散下的光谱、眼图和功率代价。10Gb/s的传输结果表明,链路色散绝对值小于1000ps/nm时,施加相位预调制的非归零信号功率代价小于1dB,比普通非归零信号具有更高的接收灵敏度和更低的色散功率代价。因此,基于相位预调制的信号整型技术可减轻系统对光信噪比和色散管理的要求,延长传输距离。     

光纤中超连续谱产生机理研究

从非线性薛定谔方程出发,分析了自相位调制(SPM)和群速度色散(GVD)效应对超连续(SC)谱的贡献。利用主动锁模光纤激光器作为泵浦光源。对色散位移光纤(DSF)中的SC谱展宽进行了实验研究。理论和实验结果表明,光纤中,SC谱的产生主要是SPM和GVD共同作用的结果：对于皮秒泵浦脉冲和常规光纤,仅考虑SPM和GVD效应,就可以较精确地描述光纤中SC谱的产生过程。     

介质膜滤波器色散特性的数值方法

文章根据介质膜滤波器为最小相位滤波器的特点,提出了一种从介质膜滤波器的幅度响应重构出相位响应,然后求出它的群速度延迟以及色散的数值方法.最后,实验验证了理论计算结果.     

光纤结构缺陷对传输特性的影响

利用自行编制的光纤分析软件数值研究了纤结构缺陷对传输特性的影响。研究结构对光纤传输特性的理解和光纤制备工艺的控制有一定的指导意义。     

基于非线性光学环镜中SOA的XPM效应生成UWB信号的研究

利用非线性光学环镜(NOLM),提出了一种基于半导体光放大器(SOA)的交叉相位调制(XPM)效应生成超宽带(UWB)信号的方法,设计了系统结构,并进行了仿真实验,得到了中心频率约为6.7GHz、相对带宽约为161%的UWB信号,该信号符合美国联邦通信委员会(FCC)标准,从而验证了该方法的可行性。另外,所生成的UWB信号的中心频率及带宽还具有可调性。     

Research on application of variable coding modulation system based on Digital Video Broadcasting ‐ Satellite ‐ 2nd Generation in data transmission of near‐earth remote sensing satellite

In order to make full use of the link resources for data transmission from near‐earth remote sensing satellites, variable coding modulation (VCM) system is used to fully utilize the system link margin to improve the satellite data transmission performance. By analyzing the dynamic link under the VCM data transmission system, the contribution of the VCM system to the satellite data link optimization is studied from the perspective of engineering application, which can provide reference for the data link design of remote sensing satellites. Applying the flow design, for the currently adopted transmission system of X band, compared with traditional constant coding modulation (CCM) system, the average link performance of VCM system can be increased by 42.1% in single‐station transmission mode and 53.3% in dual‐station relay mode through the exampled analysis.