激光大气通信系统的关键技术研究

文中介绍了大气激光通信优点,阐述了大气激光通信系统的工作原理、关键技术,并展望了未来光通信的前景.     

光发射模块研究与进展

介绍了光发射模块的工作原理、制作工艺和发展现状;详细分析了光发射模块在电路设计、封装及总体设计上的关键技术,给出了当前光发射模块的研究发展方向.     

用于"最后一公里"的自由空间光通信系统

介绍了一款FSO系统的工作原理、结构设计和系统测试结果.着重分析了系统中光学发射和接收系统以及激光发射电路和以光纤模块作为数据接口的光电接收电路设计,并对该系统进行了双向通信测试试验.     

MCU在显示器控制中的应用

隔离放大器是输入端与输出端没有电气联系的放大器.光耦合隔离放大器利用LED与光电二极管传递信号而保证电气绝缘.本文分析了Burr-Brown公司生产的ISO100的性能、工作原理和各种电路形式,介绍了调整方法和使用注意事项,并给出了它的几个应用电路实例.     

光耦合线性隔离放大器ISO1OO及其应用

隔离放大器是输入端与输出端没有电气联系的放大器.光耦合隔离放大器利用LED与光电二极管传递信号而保证电气绝缘.本文分析了Burr-Brown公司生产的ISO100的性能、工作原理和各种电路形式,介绍了调整方法和使用注意事项,并给出了它的几个应用电路实例.     

EPON技术及其应用

本文介绍了以太网无源光网络(EPON)的概念、起源和标准,并对一个EPON系统的组成和工作原理进行了分析;探讨了EPON系统中涉及的几个关键技术;最后给出了无源光网络在广电系统的一个应用实例。     

光通信技术讲座--(八):光放大器

介绍掺铒光纤放大器(EDFA)和半导体光放大器(SOA)的工作原理、特性和应用.     

光交叉连接设备(OXC)及其基本模块

OXC是实现全光网络的核心器件.介绍了光交叉连接(OXC)的主要特点和工作原理,并且深入讨论了OXC的基本模块.     

基于半导体激光器的光声光谱气体检测及其进展

介绍了半导体光声光谱气体检测的基本工作原理和相关技术,阐述了半导体激光光源特别是中红外半导体激光器的研究进展及其与光声光谱方法结合的应用现状,讨论了声信号的常用检测方法与改进方案,并展望了发展和应用的新方向.     

420C型500kW短波发射机侍服系统故障分析

本文介绍了420C型500KW短波发射机调谐系统的组成和基本工作原理,并结合工作原理,对维护中出现的故障进行了分析讲解,并对侍服系统的维护进行了探讨.     

Nonlinear Sagnac interferometer switch and its applications

Ultrafast all-optical switching based on the optical Kerr effect in a Sagnac interferometer which consists of a dichroic polarization-maintaining fiber coupler and dispersion-shifted polarization-maintaining fiber loop is reported. This nonlinear Sagnac interferometer switch has the advantage of high stability originating from completely balanced interfering arms. In addition, because dispersion-shifted fibers were used, increases in switching power and switching time were prevented. Moreover, polarization fluctuation was completely suppressed due to the all-polarization maintaining fiber configuration. The required switching power for complete switching was measured to be 1.8 W for a 200-m-long fiber. All-optical time division demultiplexing and logic operations, including inversion and operation, using the nonlinear Sagnac interferometer switch were successfully demonstrated at 5 Gb/s     

用Sagnac干涉法和固定分析法测量光纤偏振模的色散

介绍了用Sagnac干涉法和固定分析法对光纤偏振模色散的测量原理和测试实验系统。与固定分析仪测量法对比 ,Sagnac干涉法的实验装置更趋简单 ,测量光谱更具有可读性。在目前偏振模色散测量仪器价格昂贵的情况下 ,此方法具有很高的实用价值     

Broad-band mid-span spectral inversion without wavelength shift of1.7-ps optical pulses using a highly nonlinear fiber Sagnacinterferometer

We demonstrate broad-band mid-span spectral inversion without wavelength shift of short optical pulses using a highly nonlinear fiber Sagnac interferometer. The 1.55-μm optical pulses with a 1.7-ps pulsewidth are transmitted over 40 km of standard fiber, showing the suitability of this technique for broad-bandwidth second-order dispersion compensation in high-bit-rate optical fiber transmission systems     

消偏型Sagnac光纤管道泄漏检测系统及其稳定性研究

管道作为石油、天然气、自来水等的主要运输工具,其运行安全性已受到广泛关注。管道腐蚀穿孔引起的持续性小规模泄漏的及早发现与准确定位是管道运行安全的主要问题和难题。利用Sagnac光纤干涉仪对管道小泄漏进行监测和定位时,光波偏振态的随机变化直接影响到Sagnac环中两束相干光的干涉效果,从而影响直线型Sagnac光纤干涉仪的性能。提出了采用光学消偏的方法抑制偏振态对Sagnac干涉仪性能的影响。通过改进干涉仪的结构,在Sagnac环中加入光纤延时环消偏器,从而提高系统运行稳定性。实验结果表明,该方法能够较好地解决偏振态变化引起的检测灵敏度降低的问题。     

Sagnac fiber interferometer with the population grating for fiber Bragg grating dynamic strain sensing

A Sagnac fiber interferometer with the population grating formed in saturable erbium-doped fiber (EDF) for fiber Bragg grating (FBG) dynamic strain sensing is proposed. In this configuration, a semiconductor optical amplifier (SOA)-based fiber ring laser with an FBG reflector is employed in the sensing part and a Sagnac interferometer based on transient two-wave mixing (TWM) via dynamic population gratings in single-mode polarization maintaining erbium-doped fiber (PM-EDF) is used in this detecting part. Experimental results show that the Sagnac fiber interferometer detection system can stably respond to dynamic strains at high frequencies. As an example of application, the response of the sensor system to continuous sinusoidal ultrasonic signals is presented. The proposed simple and robust configuration has an all-fiber design based on commercially available elements, which makes it promising for applications in fiber optic ultrasonic sensors.     

Polarization-independent all-optical switching

A polarization-independent all-optical switch has been demonstrated based on a nonlinear fiber Sagnac interferometer. The control signal is split and recombined with a time delay, producing two linearly polarized pulses that lie within the temporal switching window of the circuit. Less than 10% variation of the switched output signal was observed as the input polarization was varied     

A variable-loop Sagnac interferometer for distributed impactsensing

A variable-loop fiber optic Sagnac interferometer is designed to locate a time-varying disturbance. Phase perturbation on a Sagnac loop produces a nonreciprocal phase signal which contains information of the perturbation location. Both location and amplitude of the perturbation can be determined by combining two phase signals from the variable-loop Sagnac interferometer. Spatial resolution better than 1 m has been demonstrated in a 180 m prototype system     

Comparison of fiber-optic Sagnac and Mach-Zehnder interferometerswith respect to thermal processes in the fiber

The impact of thermal noise in the fiber on the noise power and signal-to-noise ratio (SNR) of fiber-optic sensors is investigated, and sensors based on the Sagnac and the Mach-Zehnder interferometers are compared. The SNR is almost the same for the two interferometers; the Mach-Zehnder interferometer has slightly higher SNR at low frequencies, whereas the Sagnac interferometer may have a few dB higher SNR at high frequencies. It is also shown that thermal noise may dominate over shot noise for realistic system parameters, in which case a Sagnac interferometer has several advantages over a Mach-Zehnder interferometer     

高速光通信系统中全光解复用技术

本文介绍了3种在全光时分复用(OTDM)系统中所采用的解复用器:一是基于 Sagnac干涉仪的光纤非线性光环路镜(NOLM)解复用器,二是采用行波半导体激光放大器的非线性光环路镜(TWSLA—NOLM)解复用器,三是基于频率转换的四波混频(FWM)解复用器。解复用嚣是全光信息处理中的关键技术之一。