【作者】 向少勇；

【导师】 张新亮；

【作者基本信息】 华中科技大学 ， 光学工程， 2007， 硕士

【摘要】 光采样技术是对高比特率光学数据信号进行时间分辨测量的理想技术,它具有传统光电探测器和示波器无法达到的带宽。光采样在高比特率信号的波形和眼图测量、相位调制信号的星座图测量、偏振态时域分辨测量和光纤传输损伤研究等方面得到广泛应用。本文在湖北省杰出青年基金和教育部新世纪优秀人才计划的资助下,对光采样的实现方案和关键技术进行较深入的理论和实验研究,完成的主要工作有如下几点:(1)在广泛查阅国内外文献的基础上,综述了目前报道过的光采样的实现方案和基本原理,并对光采样中的关键技术:采样脉冲源、时钟恢复、采样门和光电探测及数据采集的实现方案分别进行概括总结。(2)分析了半导体光放大器(SOA)的三种理论模型,利用琼斯矩阵法推导了基于SOA的超快非线性干涉仪(UNI)的传输函数,并在此基础上模拟了UNI的开关窗口特性。利用折叠型干涉仪结构实验验证了20Gb/s的UNI开关特性。(3)分别以UNI和增益透明UN(IGT-UNI)作为采样门,模拟得到了在不同的SOA载流子寿命下20Gb/s NRZ和RZ伪随机序列的同步光采样眼图,并进行了对比分析。(4)对全光码型转换和差分相移键控(DPSK)信号解调进行了实验研究。分别利用UNI和延时偏振干涉仪进行了不同速率的NRZ到PRZ的转换;利用延时偏振干涉仪实现了不同速率的NRZ-DPSK到PRZ的转换以及40Gb/s NRZ-DPSK和RZ-DPSK的解调。这一部分的工作对于研究同步光采样系统中时钟恢复的实现方法以及如何利用传统的光采样技术实现对相位调制信号的采样是有益的探索。更多还原

【Abstract】 The optical sampling technique is a novel method to perform time-resolved measurements of optical data signals at high bit rates with a bandwidth that cannot be reached by conventional photodetectors and oscilloscopes. Applications of optical sampling systems include high bit rate waveform and eye diagram measurements, measurements of constellation diagrams of phase modulated data signals, time-resolved measurements of the state-of-polarization as well as investigations of fiber transmission impairments. Supported by the Science Fund for Distinguished Young Scholars of Hubei Province and the Program for the New Century Excellent Talents in University of Ministry of Education of China,the realization of optical sampling and its key techniques are studied in this paper. The main contents are listed as follows:(1) Different configurations of optical sampling systems and their principles are reviewed. The schemes of sampling pulse source, clock recovery, sampling gate, opto/electrical detection and data acquisition are summarized.(2) Three different theoretical models of semiconductor optical amplifier (SOA) are introduced. The optical power transmittance function of the ultrafast nonlinear interferometer (UNI) based on SOA is derived using the Jones formalism. Then the switch window properties of the UNI are simulated based on them. The switch window properties of the UNI at 20Gb/s are also experimentally studied using a folded structure.(3) Synchronous optical sampling eye diagrams of 20Gb/s NRZ and RZ pseudorandom binary sequence are simulated in different carriers lifetime conditions, with UNI and gain- transparent UNI (GT-UNI) as sampling gate respectively. And the results are analyzed comparatively.(4) All-optical data format conversion and differential phase-shift keying (DPSK) signals demodulation are experimentally studied. All-optical nonreturn-to-zero (NRZ) to pseudo-return- to-zero (PRZ) conversion has been achieved at different bit rate using UNI and delay polarization interferometer respectively. In addition, all-optical NRZ-DPSK to PRZ conversion at different bit rate, 40Gb/s NRZ-DPSK demodulation and 40Gb/s RZ-DPSK demodulation have been achieved using delay polarization interferometer. These works are beneficial to clock recovery in synchronous optical sampling system and DPSK signals sampling using traditional sampling technique.更多还原