A Consideration of an Optical Coupler for Optical Submarine Transmission Laser Redundancy Systems

Theoretical and experimental results are described for a new optical coupler which consists of two laser diodes, two GRIN spherical rod lenses, a polarizing filter, and a single-mode fiber, and which employs laser diode polarization characteristics for an optical submarine transmission laser redundancy system. This optical coupler has two channels at 1.3 μm wavelength. Optical coupler loss values, which include coupling loss, polarization loss, and assembly loss, are 4.9 dB for one laser diode and 5.2 dB for another laser diode. Such loss values are almost the same as the conventional laser diode module loss for a single-mode fiber. This paper describes in detail a laser redundancy system in an optical submarine transmission system, structure and characteristics of an optical coupler, and experimental results on a high bit rate long-haul transmission system using the proposed optical coupler.     

Polarization-Maintaining Optical Fibers Used for a Laser Diode Redundancy System in a Submarine Optical Repeater

Polarization-maintaining optical fibers are developed for installation in a submarine optical repeater. These fibers preserve the polarization of light emitted from laser diodes (LD's) to a single-mode fiber through a light-switching coupler. Crosstalk of less than -30 dB in a l-m length of these optical fibers, called PANDA optical fibers, is achieved with a bending radius greater than 10 mm, twists of less than 60 turns, and tension of less than 3 kg, and ambient temperatures of -20-80°C. The mechanical strength of these fibers is the same as that of single-mode fibers.     

Repeater Fault Location for a Submarine Optical Fiber Cable Transmission System

This paper introduces a repeater fault location system for a repeated submarine optical fiber transmission system of 400 Mbits/ s at 1.3μm. The repeater fault location system is used in an out-of-service test. The fault locator transmits a test signal via a main optical fiber line, in order to make a loop-back path in one of the repeaters for returning the test signals via another main optical fiber line and to measure the bit error rate (BER) of the interrogated repeater. The test signal is a kind of pseudorandom signal that includes a low frequency component, which is assigned to the repeater as a supervisory frequency tone (SVT) signal. The BER is measured by counting the number of low frequency signal phase inversions in a time. This paper first describes the test signal generating method, SVT frequency allocation, and the filter design installed in a repeater. Next, there is a discussion of how the capability of the repeater fault locator has been experimentally verified by using two submarine repeaters, including four regenerative repeater units and three submarine optical fiber cables. As a result, a BER of less than5 times 10^{-6}is accurately measured.     

海底光缆传输系统简介

随着新技术和新设备的不断出现，为未来的海底光缆传输系统的发展提供了广阔的前景。本文根据ＣＣＩＴＴ建议Ｇ．９７１、Ｇ．９７２和Ｇ．９７４，介绍海底光缆传输系统的基本组成和特性，然后讨论光纤放大器的基本原理及其在海底光缆传输系统中的应用。     

无源光器件的偏振相关损耗测量

介绍 偏振相关损耗(PDL)现已成为描述无源光器件特性的一项标准指标.当前主要有两种PDL测量方法:偏振扫描法和四状态法,后者一般也被称作Mueller法.本文将对这两种测量方法进行简要的介绍,概要说明其主要难题和主要的误差来源,并对其在当前无源器件测量中的实际应用进行比较.     

Automatic Polarization Control for Packet Transmission in a Hybrid Circuit and Packet-Switched Optical Network

We demonstrate automatic polarization control for packet transmission in an optical hybrid circuit and packet-switched network. The method combines a commercial automatic controller with a transmission scheme and a novel feedback circuit that ensures continuous feedback. Packet loss rate measurements show less than 0.1-dB power penalty when comparing packet transmission to continuous transmission. The controller causes an additional 0.3-dB power penalty.     

Servo System Using Optical Serial Transmission in Control Loop for Industrial Robots

A new servo system suitable for robot control is proposed. An optical serial transmission is applied in its servo-control loops to reduce the number of signal cables and the cable length between the robot mechanism and the controlling equipment, as well as to increase flexibility for expanding control functions.     

Quadrupling Optical Delay Range Using Polarization Properties

We describe a scheme to quadruple an optical delay using polarization properties of light in a fiber and demonstrate a fast variable delay line with a record-setting delay range of 72 mm at a speed of $sim$2 kHz (corresponding to $sim$136 m/s). The method can find various applications where a large optical delay or a high-speed delay variation is required, including optical coherent tomography, optoelectronic oscillator, programmable optical delay lines, and optical delay buffers.      

光传送网中的关键光器件

光器件是光传送网的基础单元之一，本主要综述光传送网中的关键光器件：光源与光探测器、光波分复用/解复用器、光放大器、色度色散与偏振模补偿器及光开关等。比较了各种光器件的主要技术方案，特别针对的是已实用化的技术方案。最后讨论了光器件的尺寸小型化、微型化以及多功能集成等发展趋势，介绍了光器件的集成方式如：传统分立光器件的集成，平面光波导集成，以及混合集成等。     

A Data Transmission Method Using a Cyclic Redundancy Check and Inaudible Frequencies

This paper describes a data transmission method using a cyclic redundancy check and inaudible frequencies. The proposed method uses inaudible high frequencies from 18 kHz to 22 kHz generated via the inner speaker of smart devices. Using the proposed method, the performance is evaluated by conducting data transmission tests between a smart book and smart phone. The test results confirm that the proposed method can send 32 bits of data in an average of 235 ms, the transmission success rate reaches 99.47%, and the error detection rate of the cyclic redundancy check is 0.53%.     

SDH在跨洋海底光缆系统中的应用

本文作者以亚太电信组织(APT)研究组SQ3.1研究课题(亚太国家SDH规划、实施与操作策略)专题报告人身份出席了1995年8月在泰国廊开召开的第15届APT研究组会议。结合会议上获得的技术资料和对,ITU—T有关SDH建议的了解撰写此文,介绍世界上第一条采用SDH技术的跨洋海底光缆系统TPC—5。     

海底光缆传输安全技术研究

海底光缆通信系统作为国际间和海岛通信的重要手段正发挥着越来越重要的作用,从常见的海底光缆故障和信息传输保密性两个方面分析了海底光缆传输存在的安全性问题,并提出了初步的解决方案。     

我国海底光缆通信系统标准化问题探讨

本探讨了海底光缆通信系统标准化的必要性与可行性，介绍了海底光缆通信系统的基本构成与特征，分析了国内外海底光缆通信系统的标准化状况，最后提出了我国应如何开展标准化工作的建议。     

海底光缆用色散均衡光纤

介绍了一种带正色散的单模光纤,用来均衡常用于海底光缆中的非零色散位移光纤的负色散。这种光纤类似于常规单模光纤（Ｇ．６５２光纤）,但具有较低的衰减和较小的宏弯损耗。由于这种光纤应用常规的掺锗纤芯和纯ＳｉＯ２包层,与目前常用的纯ＳｉＯ２纤芯和掺氟包层的色散均衡光纤相比,在成本上具有较大的优越性。     

Optical Fiber Submarine Cable System Development at KDD

An optical fiber submarine cable system using longwavelength and single-mode optical fiber is expected to provide economical long-haul digital transmission. This paper describes the recent research and development on an optical fiber submarine cable system for international communication at the KDD Research and Development Laboratories. An experimental model including cable and repeaters has been designed and manufactured. An experimental repeater of 1.3 μm and 280 Mbits/s was laid at a depth of 1500 m and its fundamental performance was measured in November 1981. Test production of longlength cable having a single continuous length of 30 km became possible in the end of 1981. In early June 1982, the experimental system with a 50 km cable length and two repeaters operating at 300 Mbits/s and 1.3 μm wavelength was laid in a loop into the Sagami Bay from the KDD Ninomiya Submarine Cable Landing Station.     

The Effect of Polarization Mode Dispersion on the Transmission System Using Dispersion Compensation Fiber

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基于半导体光放大器非线性偏振旋转效应的全光采样

提出了一种新的基于半导体光放大器非线性偏振旋转效应的全光采样方法,利用速率方程对全光采样的理论机理进行了阐述.借助该速率方程模型对采样器的输入偏振角、偏振控制器的附加相移和偏振合束器的偏振方向等参数进行了优化设计.计算结果表明,采样器传输曲线具有较好的线性工作范围,能够实现模拟光信号的高速全光采样,且其输入泵浦光功率小于1mW.由于该全光采样的工作原理与全光波长转换类似,而目前的全光波长转换工作速率可达320Gbps,因此该全光采样的采样速率可望达到上百GS/s.     

基于半导体光放大器非线性偏振旋转效应的全光采样

提出了一种新的基于半导体光放大器非线性偏振旋转效应的全光采样方法,利用速率方程对全光采样的理论机理进行了阐述.借助该速率方程模型对采样器的输入偏振角、偏振控制器的附加相移和偏振合束器的偏振方向等参数进行了优化设计.计算结果表明,采样器传输曲线具有较好的线性工作范围,能够实现模拟光信号的高速全光采样,且其输入泵浦光功率小于1mW.由于该全光采样的工作原理与全光波长转换类似,而目前的全光波长转换工作速率可达320Gbps,因此该全光采样的采样速率可望达到上百GS/s.     

Microwave Signal Generation and Transmission Based on Optical Frequency Multiplication With a Polarization Interferometer

A novel scheme is proposed and experimentally demonstrated for the generation of microwaves, based on the optical frequency multiplication principle employing a polarization interferometer. Generation of 120-Mb/s 64-quadrature-amplitude-modulation microwave signals at 40 and 24 GHz and its transmission over 25 km of single-mode fiber and 4.4 km of multimode fiber, respectively, are successfully demonstrated. The scheme is robust against laser phase noise, presents tolerance against dispersion impairments in transmission, and shows high-performance stability.     

计算机信号小型光纤传输系统的研制

光纤传输系统在计算机信号的防电磁干扰、防信息泄漏等方面具有重要作用,采用多芯光纤连接器、大芯径光纤、光窗型光电器件、表面安装技术(SMT)等实现了计算机中多路信号的小型化光纤传输,该系统达到了设计指标要求.