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随着大于40 Gb/s高速光通信系统的出现, 为了保证光信号传输质量, 需要对光信号进行监测。对于带宽超过传统光电探测器和示波器可测量带宽的高比特率数据光信号, 光采样技术是进行时域测量的重要手段。采用固定频差的方法可以用百兆速率的采样脉冲对高速光信号进行采样, 降低了对采样后电数据处理系统带宽的要求。在对基于周期极化铌酸锂(PPLN)波导中和频效应的采样过程进行建模仿真的基础上, 实现了对Optsim获得的光传输线内10 Gb/s的非归零码(NRZ)和归零码(RZ)信号的采样。采用软件同步算法对采样数据进行处理, 获得信号的眼图, 这一方法可使采样系统对硬件的要求降到最低。与理想与门获得的采样结果进行比较, 对PPLN波导的光采样特性和采样质量进行了分析。 相似文献
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A tunable optical rail is embedded into the cavity of a nonlinear-polarization-rotation(NPR) mode-locked fiber laser to generate a sampling pulse with different repetition frequencies and realize bit-rate-adaptive software synchronous optical sampling.Two ultrashort pulses(20.26677 and 20.22900 MHz) are derived,and a 100-MHz data signal is sampled twice with these pulses based on sum-frequency generation(SFG) in periodically poled lithium niobate(PPLN).The eye diagram is successfully recovered,and an estimated bit rate of 102.22 MHz is derived.This method is feasible for bit rates ranging from 200 MHz to 1 GHz,with <3% relative error. 相似文献
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The robustness of the software-synchronized all-optical sampling for optical performance monitoring is estimated for 10-Gb/s fiber communication systems. It reveals that the software-synchronized algorithm is sensitive to the signal degradation caused by chromatic dispersion and nonlinearity in optical fibers. The influence of timing jitter and amplitude fluctuation of the sampling pulses is also investigated. It is found that stringent requirements are imposed on the quality of the sampling pulse and the tolerance of 1-dB Q penalty is measured. Considering the practically available optical sampling pulse sources, the results indicate that the amplitude fluctuation of the sampling pulses has the dominant impacts on the software-synchronized method. 相似文献
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A software synchronous optical sampling system is constructed based on sum frequency generation (SFG) in periodically poled lithium niobate (PPLN). Five gigahertz of a non-return-to-zero (NRZ) data signal is sampled by sampling pulse with the repetition frequency of 29.31 MHz. The power of the SFG light is set at 23 dBm, and an eye diagram is successfully recovered. A band-pass filter is added before the sampling pulse is subjected to erbium-doped fiber amplifier to reduce gain competition and ensure a high power level of SFG. 相似文献
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农民教育培训的思考和对策 总被引:1,自引:0,他引:1
<正>农村劳动力逐渐向城市转移,这已是我国社会发展中不可逆转的趋势。近几年来,虽然农民从事非农产业的收入已成为农民增收的主渠道,但由于农村劳动力素质不高,缺乏 相似文献
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杨爱英 《北京联合大学学报(自然科学版)》2000,(Z2)
社会的快速发展要求我们培养出具有较强交际语言能力的外语人才 ,而传统的教学方法显然不能适应新时期的要求。通过多年的大学英语教学实践并结合教学理论 ,认为朗读是对有一定外语基础的学生的高级要求 ,是培养他们由吸收知识到运用知识的有效途径之一 ;加强朗读训练有利于听、说、读、写、译综合能力的提高 ,有利于培养学生适应新时期的社会工作。因此 ,朗读应该在大学外语教学中大力提倡 相似文献
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