有源光纤器件的进展

目前有了许多有源的光纤器件,包括光纤放大器、激光器及谐波发生器。这些器件及不久要发展的可调参数光纤光源,将会在实际中得到广泛的应用。     

基于液体填充微结构光纤的新型光子功能器件

基于液体材料填充的微结构光纤光子器件有效地将功能材料在不同外界物理场作用下的物理效应同光纤自身的微纳结构结合起来,具有可调谐、设计灵活、全光纤结构和易于集成等优点,是未来光纤光子器件发展的重要方向。掌握不同填充材料、填充方法及所制作器件的不同特性、功能和应用对这一领域的研究具有重要的指导意义。综合阐述了近年来基于液体材料填充的微结构光纤光子器件的研究进展,分析和归纳了各种液态功能材料的种类、物理特性及填充方法,系统阐述了基于该种方法实现的光开关及衰减器、滤波器、调制器、色散补偿器等可调谐光纤光子器件及光纤传感器件,最后对该领域未来的发展方向和前景进行了展望,为未来新型光纤光子器件的研制提供必要的依据和参考。     

基于微纳光纤的通信器件研究进展

详细介绍了基于不同种类微纳光纤的光源、光耦合器、光开关和滤波器的结构、工作过程及性能参数,总结了基于微纳光纤的光纤通信器件的研究进展情况。指出微纳光纤器件的实用化是光纤通信器件的发展方向。     

固态锥形光纤器件

本文介绍两种基于锥形单模光纤的新颖的渐逝场器件。这两种器件都是将单模光纤拉成腰部直径约２μｍ的锥形体，以便保持接近于１００％的传输效率。第一种器件中，对含荧光材料的溶胶－凝胶连结覆层进行烘烤。它是通过吸收特性及荧光特性的变化而主要应用于传感领域的。第二种器件中，锥形体被在同样也含有荧光材料的聚乙酸乙烯酯溶液里，经凝固后形成固体器件。     

高功率光纤熔融器件设计综述

近年来,高功率光纤激光发展迅猛,基于光纤熔融器件的全光纤激光系统可以更好地发挥出光纤激光所固有的体积小、质量轻、稳定性和可靠性高等优势。高功率条件下,器件局部发热可能给器件带来灾难性的故障。决定器件高功率承受能力的不是传输功率,而是器件处理光功率损耗的能力。本文详细分析了单模器件和多模器件中的损耗产生机制,指出了低损耗设计的实现方法。减小器件封装的热阻也可以提高器件的功率耐受能力,文中对封装的设计给出了实用的建议。     

飞秒激光脉冲精密制作微流光纤器件及其应用

微流光纤器件是一种性能优良、应用广泛的集成光子器件。本文详细论述了飞秒激光脉冲在普通单模光纤和光子晶体光纤中制作微流光纤器件的方法,并对其应用进行概述与展望。随着飞秒激光精细加工技术的发展,将会制作出性能更加优良的微流光纤器件,推动集成光子学的进一步发展。     

偏振器件在通信和传感中的应用

偏振器件是光纤通信和光纤传感系统中的重要器件.随着光纤光学的发展,偏振器件的应用越来越广泛,并且开发出了许多新的类型.为此总结了偏振器件在光纤通信及光纤传感领域中的应用,并对偏振器件的研究方向作了展望.     

光纤无源器件市场概况和预测

随着光纤通信技术和应用的发展,光纤无源器件的重要性愈显突出,并孕育了大量市场机会。在光纤无源器件中,形成较大市场的产品主要是光纤连接器、光纤耦合器、波分复用器和光开关四大类。     

光纤制导技术及器件的发展研究

光纤技术在有线制导武器方面的应用是光纤技术军事应用的一个重要方面，光纤制导技术具有信息传输容量大、抗干扰能力强、制导精度高、隐蔽性好等一系列优点，因此光纤制导技术及器件日益受到各国政府和军方的重视。简要介绍了光纤制导的关键技术，详细叙述了光纤制导技术在光纤制导导弹、光纤制导鱼雷、光纤制导水下武器和诱饵中的应用和发展，汇总了世界各国光纤制导导弹、光纤制导鱼雷和光纤制导导弹系统的研制项目发展状况以及光纤制导水下武器和诱饵的应用和发展，指出制导光纤、制导光缆、制导光纤陀螺和制导光纤水听器的发展现状和趋势，分析了我国光纤制导技术及器件与国外的差距，并提出加快我国光纤制导技术发展的建议。     

基于材料填充的可调光子晶体光纤器件

详细阐述了最近几年基于材料填充的可调光子晶体光纤器件的研究进展,以及发展可调光子晶体器件的重要意义。并根据调制方法的不同,进行了归类介绍：热调器件,电调器件,光调器件。对基于材料填充的可调光子晶体光纤器件的前景进行了展望。     

Realization of broad-band phase devices by using W-typeeccentric-core optical fibers

Axially nonsymmetric W-type optical fibers are proposed as broadband phase devices for optical-fiber systems to provide the Fresnel's rhomb retarder in classical optical systems. Propagation characteristics of the W-type eccentric-core optical fibers are investigated theoretically using the boundary-integral method. The results of the numerical analysis indicate that such broadband phase devices can be realized by using the wavelength-dependent birefringence of axially nonsymmetric W-type optical fibers. It is theoretically found in the case of eccentric cores that a relative bandwidth of 18.2% with a phase retardation error of 2% is realizable without the propagation of higher-order mode waves     

Fiber-optic devices for local area network application

Recent developments on fiber-optic devices are reviewed from the local area network (LAN) application viewpoint. Future technical trends are also discussed, along with current research activities. In local area network systems, low device cost and easy maintenance or maintenance-free devices are especially required. Light sources and photodetectors suitable for the systems are described. InGaAsP/InP light emitting diodes can cover a broad application field, up to a gigabits per second super high-speed network region. Optical passive devices, which include branching couplers, switches and connectors, are mentioned as essential components. Compact transmitter/receiver module technology is a key factor in realizing optical-fiber local area network systems. An example of 200-Mbit/s transmitter/receiver module is reported.     

Optical-transmission characteristics of optical-fiber cables and installed optical-fiber cable networks for WDM systems

Many cables containing 1.3-/spl mu/m zero-dispersion single-mode (SM) optical fibers are installed in trunk and access networks. Recently, there have been a number of studies on wavelength-division-multiplexing (WDM) systems designed to increase transmission capacity and flexibility. If we can construct WDM systems using SM optical-fiber cable networks designed to transmit using wavelengths in the 1.3-/spl mu/m window (O-band), this will prove very effective in reducing construction costs. It is therefore important to examine the wavelength dependence of the transmission characteristics of SM optical-fiber cables and networks that have already been installed and in which several optical fibers are joined. In this paper, we describe the measured optical characteristics of SM optical-fiber cables and installed optical-fiber cable networks at various wavelengths. The optical characteristics were stable in the 1.46 to 1.625-/spl mu/m wavelength range and we confirmed that the installed SM optical-fiber cable networks could be used for WDM system applications.     

Estimation of submarine optical-fiber cable elongation

The tensile strain on a submarine optical-fiber cable may reach a nonlinear elastic region when recovered from the sea floor. In this paper, a method is shown to characterize cable elongation up to the nonlinear plastic region by extending wire theory previously developed to evaluate cable strain in the elastic linear region. The results of applying this method to several optical-fiber cables agrees well with tensile test results of the cables when cable ends are prevented from twisting, as well as when they are free to rotate. Also, by evaluating the dependence of cable strain on cable materials, such as stranded-strength members and pressure-resistant conductor pipe, a practical submarine optical-fiber cable structure for deep-sea use is determined.     

Recirculating loop for experimental evaluation of EDFA saturatedregime effects on optical communication systems

We demonstrate an optical-fiber recirculating loop for experimental simulation of long-haul optical communication systems using cascaded erbium-doped fiber amplifiers (EDFA's) operating in the gain saturation regime. The loop contains sections of dispersion shifted fibers (DSF's), standard fiber, and a set of in-line devices, such as tuning filters, optical amplifiers, polarization controllers, and a variable attenuator. The main results presented here are related to the observation of the effects due to the slow dynamics of the EDFA. We also discuss the validity of using an optical attenuator to simulate an extra length of fiber     

布里渊光时域分析仪与马赫-曾德尔干涉仪共同检测传感技术

布里渊分布式光纤传感器适用于测量静态的温度/应力,而马赫-曾德尔干涉仪分布式光纤传感器(DOFS)可测量动态的应变变化。许多应用场合需要静态和动态的传感信息,这是单机理分布式光纤传感器难以达到的。由于布里渊光时域分析仪(BOTDA)和马赫-曾德尔干涉传感器都采用双向环路传感光纤结构,通过共用光源和主要光器件,将布里渊光时域分析仪和马赫-曾德尔干涉传感器相结合。利用布里渊传感测温度,马赫-曾德尔传感器测振动,从而可实现多机理多参量传感。搭建了25 km传感实验系统,对于马赫-曾德尔振动传感,定位精度达到60 m,并可计算振动频率;对于布里渊传感,在没有振动时传感光纤的始端和末端都为2 ℃的测量精度,但在振动时得到始端为3 ℃、末端为4 ℃的测量精度。     

基于FPGA和DSP的微振动传感器信号采集系统设计

为实现对双M-Z型光纤微振动传感器的振动信号进行实时检测和处理,提出一种基于FPGA和DSP的数据采集和实时处理系统。通过描述系统的硬件设计原理和寄存器配置,以及软件框架和流程,介绍了系统的设计和实现方法。经验证,该系统实现对微振动传感器的实时数据采集并实时进行信号处理,能满足微振动传感器系统对实时性的要求。该系统具有可重构性,方便实现不同算法。     

Use of long-wavelength devices for analog optical-fiber loops

This paper reports on experimental investigations in the use of available long-wavelength (1.3-1.55-mum) devices in wide-band analog optical-fiber loops assumed functioning in a conventional star-configured switched network. Since for economic reasons analog TV transmission will remain attractive for the foreseeable future, the objective of this work is to extend loop length from 2 km (now feasible) to about 10 km. Distances of up to 10 km are needed to accommodate three or four television channels (each switchable) and narrow-band (NB) services. It is shown that with available "experimental" long-wavelength LED's and p-i-n photodiodes distances up to about 10 km are feasible.     

Analysis of a damage sensor based on elastic-plastic metal coatingson optical fibers

Optical-fiber sensors coated with linear work hardening elastic-plastic materials are analytically explored to determine the effects the coating properties have on the sensor performance. The optical-fiber system is analytically subjected to both an axial load and a uniform thermal gradient. The nonlinear analysis reveals a mechanism for designing coatings which provide a memory to the optical-fiber sensor by undergoing permanent deformations in response to large thermal or mechanical strain excursions. This behavior is exploited to design a damage sensor     

On turbo code decoder performance in optical-fiber communication systems with dominating ASE noise

In this paper, we study the effects of different ASE noise models on the performance of turbo code (TC) decoders. A soft-decoding algorithm, the Bahl, Cocke, Jelinek, and Raviv (BCJR) decoding algorithm, is generally used in TC decoders. The BCJR algorithm is a maximum a posteriori probability (MAP) algorithm, and is very sensitive to noise statistics. The Gaussian approximation of ASE noise is widely used in the study of optical-fiber communication systems, and there exist standard TCs for additive white Gaussian noise (AWGN) channels. We show that using a MAP decoding algorithm based on the Gaussian noise assumptions, however, may significantly degrade the TC decoder performance in an optical-fiber channel with non-Gaussian ASE noise. To take full advantage of TC, accurate noise statistics in optical-fiber transmissions should be used in the MAP decoding algorithm.