Highly linear transmission and EVM improvement of vector modulation signals for radio-over-fiber applications

The principle of error vector magnitude (EVM) against modulator nonlinearity for vector modulation signal (VMS) transmission in radio-over-fiber (RoF) systems is theoretically and experimentally investigated. A highly linear modulation scheme is proposed and demonstrated using a single-drive dual parallel Mach-Zehnder modulator (MZM). This method improves EVM performance and enlarges the linear input dynamic range of the VMS transmission. An index of maximum allowable input power difference (MAIPD) that reflects the difference of upper input power limits between these two schemes is measured. An EVM limitation of 5% MAIPD has 5 dB. Both 16and 64-QAM results indicate that the proposed scheme supports VMS transmission better than the MZM one.     

高阶非线性极化率图示法的化简研究

本文推演出密度矩阵元拓扑图示的最简约化方法.应用这方法,仅用n 1个拓扑图即可完备表征n阶非线性极化率, 与此同时还给出表达式中每一项的微观通道数.     

外色散腔半导体激光器的单模运转

本文对外色散腔半导体激光器单模工作条件及机理进行了理论分析和实验研究。采用将多纵模输出的半导体激光二极管置于外色散腔内,不论二极管表面镀不镀增透膜,都实现了室温连续稳定单纵模运转。激光线宽小于50MHz,调谐范围200(?),单模功率大于无外腔时的多模输出功率,可达3mW。     

长波长1.3μm直接调制InGaAsP/InP半导体激光器产生超短光脉冲

利用长波长1.3μm InGaAsP/InP半导体激光器,在直接调制下获得了重复频率为1GHz,脉宽为19.3ps的超短脉冲。     

双锥光纤模拟理论方法

从双锥光纤的工艺实现和技术应用目的出发,建立了可与实验上易测量的工艺参数相联系的高期型等效双锥光纤模拟理论方法,可用于双锥光纤的制作及光学特性的分析,数值模拟结果与实验符合得很好。     

利用半导体激光放大器作为高速光调制开关的2Gbit/s光学时分复用实验

本文报道利用半导性激光放大器作为高速开关,进行了2Gbit/s的光学时分复用发射实验。     

Tunable multi-wavelength microwave photonic filter based on the superposition of transfer functions

A microwave photonic filter （MPF） with reconfigurability and tunability resulting from the superposition of the transfer functions is proposed. Based on the Vernier effect between the optical frequency combs and the periodic optical filters, each comb line can be mapped into a sub-filter in the electronic field. The sub-filters are superposed to obtain the total transfer function of the MPF. By manipulating a few comb lines, we can reconfigure the passband shape, tune the bandwidth, and adjust the center frequency independently. Experiments verify that the bandwidth can be tuned from 224.8 to 674.3 MHz, and that the center frequency ranges from 1 to 4 CHz.     

以半导体激光器为光源的光孤子传输理论分析

建立了一个包括半导体激光器超短光脉冲产生、法布里－珀罗光谱窗消啁啾、在有损光纤及集总光纤放大器组成的链路中进行非线性传输的整体简化理论模型，并利用这一模型进行了数值模拟计算和分析。结果表明，此模型能较真实地反映入射光纤的光脉冲的时域及频域特性，模拟计算所得的结果与实验结果符合得较好。同时还证明了利用法布里－珀罗光谱窗消啁啾后的准孤子脉冲可以用于光孤子传输。     

利用半导体激光放大器放大半导体激光超短脉冲及选取单模

本文对半行波半导体激光放大器的超短光脉冲响应进行了研究,结果表明:脉宽为27ps,重复频率为1GHz的超短光脉冲通过放大器后,脉冲没有展宽,并且由于半行波半导体激光放大器对波长的选择放大性,在输入为多模的情况下,获得了单模超短脉冲输出。     

短耦合腔半导体激光器单纵模工作特性

引入附加损耗参数以反映短耦合腔的影响并利用修正约多模速率方程对短耦合腔半导体激光器单纵模工作机理和特性进行了研究,结果表明:在半导体激光二极管表面镀增透膜将使单模特性得到很大改善.实验验证了理论分析.设计研制的新型器件在连续和150MHz调制工作条件下,稳定单模输出的边模抑制比达到35～40dB.