一种小型光纤流体压力传感器的设计

本文论述一种小型光纤流体压力传感器的设计方法。这种传感器利用两根光纤分别作为光信号的发射器和接收器,在一根导管内顺序放置多个传感器,从而实现小型复杂结构的压力准确测量。该传感器的体积小、重量轻、对电磁场和化学反应不敏感,在解决压力的实时监控有重要的应用价值。文章首先介绍了小型流体压力传感器的设计要求和现有的设计方案,说明了流体压力传感器中光纤的方向性对传感器设计的影响,提出了采用硅凝胶作为压力变送元件的设计方案,并从静态特性和动态链性两个方面验证了这种方案。     

An optical fiber transducer for single myofibril force measurement

A force transducer has been developed for use in force measurement of skeletal muscle myofibrils. The transducer is suitable for measurement of passive and contractile forces in a range up to 200 μg, with 1 μg resolution. It is based upon the operating principle of the deflection of an optical fiber of known compliance, sensed by the differential illumination of two phototransistors. Attractive features include ease of operation and specimen mounting, high bandwidth, adaptability for different force ranges, and simple and inexpensive construction     

Miniaturized pressure transducer intended for intravascular use

A pressure transducer utilizing an electrooptical method is described. As the transducer is primarily intended for intravascular use, it has been given the form of a catheter with the pressure-sensing part at the one end and the necessary bulky components at the other end. A light guide of glass fibers inside the catheter transports light from a light source to the measuring tip. Here the pressure variations affect a movable membrane which reflects a variable amount of light into another light guide leading to a photodetector. The variations in the signal from the detector are thus proportional to the applied pressure. The main part of the paper is concerned with a theoretical investigation of the principle for transducers of this type. This analysis gives relationships between the geometry of the measuring tip, the number of glass fibers, and their distribution, material constants, and signal parameters. Using these relations, it is possible to arrive at the fundamental limitations of the method, particularly in regard to the miniaturization. Furthermore, some temperature effects which are generally neglected, are analyzed.     

Receiver design for optical fiber systems

This paper is a tutorial review of the theory and practice of receiver design for optical fiber communication systems. Topics discussed include fundamental limitations on performance; design and performance limitations of laboratory receivers; and practical design trade-offs and their effects on the performance of real system receivers.     

Reliability of optical components for use in submarine optical fiber transmission systems

This paper presents the reliability test results for LD modules, optical couplers, and APD modules, which are fabricated through methods for achieving and assuring a high degree of reliability for use in 400-Mbit/s submarine optical fiber transmission systems. In particular, the paper presents methods for evaluating the optical component reliability as well as an investigation into the degradation factors in the coupling circuits. From the reliability test results obtained, the paper also discusses the mechanism and test acceleration of wear-out degradation following reliability tests conducted for more than 8000 h on the fabricated optical components. These optical components are consequently confirmed to be highly reliable for a system life of 25 years.     

Reliability of fluoride fiber module for optical amplifier use

We report reliability test results for a fluoride fiber module. We developed a sealed fluoride fiber module for practical optical fiber amplifier use. Trouble-free damp heat storage and low-temperature storage for 5000 h and trouble-free temperature cycling and temperature-humidity cycling tests revealed that our fluoride fiber module has long-term stability under practical environmental conditions     

Optimum design of Nd-doped fiber optical amplifiers

The waveguide parameters for a Nd-doped fluoride (Nd:ZBLANP) fiber amplifier have been optimized for small-signal and booster operation using an accurate numerical model. The optimum cutoff wavelength is shown to be 800 nm and the numerical aperture should be made as large as possible. Around 80% booster quantum conversion efficiency can be reached for an input power of 10 dBm and a pump power of 100 mW by the use of one filter     

自由空间光通讯中应用的光纤耦合系统设计

在分析光纤通信、光纤传感等系统光纤耦合特点的基础上,讨论了自由空间光通讯系统光纤耦合前端的设计理念和总体要求。给出了针对840m通讯波段的光纤耦合系统设计实例,并且对设计优化结果进行了分析。     

光子晶体光纤压力传感器光源方案设计

文章推导出PCF压力传感器检测基本原理,设计出PCF压力传感器典型系统结构,分析了PCF压力传感器对光源的特殊性能要求,选择半导体激光器(LD)作为传感器系统光源。提出LD工作稳定性整体控制设计方案,采用路分析方法给出LD中噪声控制模块、功率控制模块、温度控制制模块和波长控制系统。在LD中通过噪声、功率和温度控制等能够有效保障LD工作稳定性,保障PCF压力传感器系统对压力测量的精确性。     

光纤电压互感器信号采集与通信接口设计

以N17813R智能数据采集卡为核心,硬件上利用信号调理电路板、数据采集卡、计算机构建光纤电压互感器信号采集系统;软件上以LabVIEW作为编程工具,分别在FPGA和主机上设计FPGA VI和HOSTVI,在FPGA上对信号进行解调处理,在计算机上对采集数据进行实时显示与记录.为了满足数字化变电站网络化的需求,采集系统采用以太网接口输出,因此对以太网输出的硬件和软件设计进行了全面的论述,并在最后给出仿真结果.     

Characteristics of magneto-optic fiber Bragg gratings for use in optical signal processing

The characteristics of photonic bandgaps and the transmission/reflection of guided optical waves in the magneto-optic fiber Bragg grating (MFBG) are theoretically investigated for the first time. The polarization-mode conversion resulting from the Faraday effect may change the width of the pure bandgap, or even lead to a couple of photonic semitransparent frequency band (STB) for sufficiently large magneto-optical-to-grating coupling ratio (MGR). Within the STBs, the transmittivity and reflectivity are equal and then the MFBG can serve as a 3 dB light beam splitter. Based on the sensitivity of MFBG spectral lines to the magneto-optic (MO) coupling coefficient, a novel high-resolution magnetic field sensor capable of up to 0.01 nm/(kA/m) is predicted. According to the dependency of nonlinear transmission or reflection on the MO effects, a new class of MFBG-based nonlinear optical switches under an appropriate MO bias may also be achieved with applications to flexible and controllable optical signal processing.     

千兆光纤以太网交换机中CONSOLE管理的设计和实现

介绍了利用TI公司的UART扩展芯片16C550C来扩展ARM11的串口,实现CONSOLE管理的设计方案,使用户可以通过控制台访问和设置交换机,无需更多复杂的终端模拟程序。控制台管理允许没有丰富技术知识的人员简单、快速地设置交换机,从而降低了部署成本。     

Polarization-modulation diagnostics of thermal stresses in an integrated pressure transducer

A semiconductor pressure transducer consisting of a sensing resistor implanted into a silicon membrane as an elastic mechanical element is studied by the modulation polarimetry technique. Internal mechanical stresses are detected. The coordinate distributions of uniaxial stresses are measured in two cases: stresses remaining from local crystal doping inhomogeneities and stresses caused by heating by flowing current. The coordinate distribution of the temperature caused by the heat flux released by the resistor current is determined by double integration of the stress function, taking into account corresponding boundary conditions.     

Structural analysis of jacketed optical fiber under lateral pressure

A theory is presented on the deformation of jacketed fibers due to lateral pressure, and its influence on microbending losses is assessed. This analysis, which is based on the theory Of elasticity, helps to clarify how lateral pressure and the structure of the fiber jacket conspire to cause excess fiber losses. Periodic pressure distributions with certain unfavorable period lengths are shown to lead to a pronounced enhancement of excess losses.     

Diaphragm design guidelines and an optical pressure sensor based on MEMS technique

The design guidelines for micro diaphragm-type pressure sensors have been established by characterization of the relationships among diaphragm thickness, side length, sensitivity, and resonant frequency. According to the study, the thickness need to be thin and the side length need to be small in order to get the sensitive diaphragm with high resonant frequency. A Fabry-Perot based pressure sensor has been designed based on the guidelines, fabricated and characterized. In principle, the sensor is made according to Fabry-Perot interference, which is placed on a micro-machined rectangular silicon membrane as a pressure-sensitive element. A fiber-optic readout scheme has been used to monitor sensor membrane deflection. The experimental results show that the sensor has a very high sensitivity of 28.6 mV/Pa, resolution of 2.8 Pa, and up to 91 kHz dynamic response.     

The feasibility of a heterode pressure transducer

Several simple pressure transducers have been built by using heterode strain sensors evaporated directly onto a pressure diaphragm. The performance of these units indicates that pressure transducers are a feasible area of application for the heterode strain sensor, and that such transducers are potentially inexpensive and easily adapted to a variety of pressure ranges.     

实时仿真系统用光纤反射内存卡的设计

本文介绍了一种光纤反射内存卡,采用FPGA实现各种接口及数据的控制;板载SDRAM作为数据的缓存;双向高速光模块实现信号收发一体化,借助光纤网络实现低延迟高速的实时数据传输.本板卡经过测试,传输速率大于2.5Gbps,传输延迟低-400ns,且传输延迟具有确定性和可预测性.     

薄膜型光纤温度传感器的膜系设计

纳米薄膜与光纤的结合为新型感测提供了各种潜在可能.为了分析温度敏感薄膜的膜系设计及其对光纤温度传感器传感特性的影响,根据光学薄膜理论和光纤传感器的温度感测原理,探讨了光纤温度传感器中敏感薄膜的膜系设计,并构建了薄膜型光纤传感器的温度传感特性模型.以测试系统的参数、性能以及其对干涉光谱的要求为基础,设计了对称性较好的法布...     

Intramodal part of the transfer function for an optical fiber

Intramodal contributions in measurements of optical-fiber bandwidth are investigated theoretically and experimentally in the quasimonochromatic case. A relation is established between the intramodal transfer function and a possibly non-Gaussian source spectrum, which may also vary with modulation frequency. By considering the latter variation in particular, we are able to predict the intramodal length dependence and show how it may deviate from that of a conventional approach.