声光可调谐滤波器及其在成像光谱仪上的应用

本文介绍了声光可调谐滤波器作为色散元件的原理,并着重对声光可调谐滤波器在成像光谱仪上的应用进行了描述。     

声光可调谐滤波器的成像光谱技术探讨

声光可调谐滤波器是一中新型的分光器件,它不仅能够通过复色光衍射出较窄的单色光,而且在与传统的光谱技术进行比较的过程中,其更具有自身的特点,满足高光谱成像探测要求。文章从声光可调谐滤波器的原理出发,对声光可调谐滤波器的成像光谱技术进行详细的分析和阐述,并根据声光可调谐滤波器成像光谱仪的室外实验对成像的技术进行探讨。     

全光纤声光可调谐滤波器声信号调理电路设计

声波信号的质量对于全光纤声光可调谐滤波器的滤波稳定性及调谐范围等都起着重要作用.该文设计制作的声信号调理电路有效满足了全光纤声光可调谐滤波器对声波信号频率、幅度、失真度等参数的要求.将该电路应用于光纤光栅声光可调谐滤波器的声信号控制实验中,实现了输出波长在声波信号控制下快速、稳定的连续调谐.     

材料特性对声光可调滤波器光谱分辨率的影响

声光可调谐滤波器(AOTF)是一种利用各向异性介质中的声光作用工作的快速可调谐的分光元件,通过调节所加载的超声波频率可实现对出射光波长进行灵活、快速地调节.光谱分辨率是评价声光可调滤波器性能的主要指标之一.以二氧化碲非共线声光可调滤波器为研究对象,基于声光作用基本原理,系统推导了非共线声光可调滤波器光谱分辨率公式,并分...     

射频反馈法实现声光可调谐滤波器

在集成声光可调谐滤波器(AOTF)工作时,由于环境温度变化以及自身声表面波吸收使器件的温度发生变化,导致滤出波的中心波长发生漂移.在理论分析的基础上,对声光可调谐滤波器的温度特性进行了实验研究,并在此基础上提出一种新的解决方案:用动态控制射频信号来实现声光可调谐滤波器的稳频输出,并用该方案实现了中心波长的漂移控制在0.08 nm以内,满足了波分复用(WDM)通信系统的应用要求.     

射频反馈法实现声光可调谐滤波器稳频输出

在集成声光可调谐滤波器(AOTF)工作时,由于环境温度变化以及自身声表面波吸收使器件的温度发生变化,导致滤出波的中心波长发生漂移。在理论分析的基础上,对声光可调谐滤波器的温度特性进行了实验研究,并在此基础上提出一种新的解决方案:用动态控制射频信号来实现声光可调谐滤波器的稳频输出,并用该方案实现了中心波长的漂移控制在0.08 nm以内,满足了波分复用(WDM)通信系统的应用要求。     

全光纤AOTF的发展与应用

光纤可调谐滤波器作为潜力巨大的光通信器件 ,近年来得到人们的广泛重视。声光可调谐滤波器具有制作工艺简单、插入损耗低、调谐范围宽、高速连续电调谐、多波长独立操作的优点 ,因而在未来全光网络中具有广泛的应用前景。对两种不同模式耦合原理进行了比较 ,介绍了声光可调谐滤波器的研究进展情况 ,分析了器件制作中主要存在的问题 ,并提出了器件在光通信系统中的应用和应用中存在的一些潜在问题。     

一般相位匹配条件下声光可调谐滤波器系统的理论分析

研究非共线性声光可调谐滤波器(AOTF)在一般相位匹配条件下的声光相互作用关系。对于通常设计制造的声光可调谐滤波器,它的o光和e光具有不同的波长,应用中无法同时使用此两束衍射光,为了使可用光强增大,应当使两束衍射光的波长相等。研究了使一般声光可调谐滤波器晶体两束衍射光波长相等的方法。对于未按照等值点理论制造的声光可调谐滤波器晶体,可以使入射光与晶体表面的法线成一个小的角度,根据一般相位匹配原理可以使两束光的出射波长相等。在实验中证明此方法的正确性,此角度称为等值偏置角。对于不同数值的衍射波长,有不同的等值偏置角,最后给出了等值偏置角随衍射波长的变化规律。     

可调谐光滤波器及其WDM应用

可调光滤波器技术是波分复用系统的关键技术之一,它对于发展全光网络具有极其重要的作用。文章介绍了几种具有潜力的可调谐光滤波器,包括：光纤光栅可调谐滤波器、声光可调滤波器、阵列波导光栅滤波器和光子晶体滤波器等,并分析了它们的工作原理及其在波分复用系统中的应用。     

超光谱成像仪

Chromo Dynamics公司的HSi-300超光谱成像仪是基于该公司的声光可调谐滤波器（AOTF）成像模块研制而成的。该系统包括1个集成的EMCCD相机、1个声光可调谐滤波器（AOTF）、仪器驱动和控制模块以及直观的影像像捕捉和超光谱分析软件。     

ROADM技术简介及演进方向

阐述了可重构型光分插复用设备(ROADM)进入波分网络的背景,并对ROADM的3种主要技术进行了简要介绍。最后提出未来ROADM的发展方向,即ROADM光层调度 OTN电层调度组合解决方案,以及中兴通讯推出的适应市场发展的设备功能类型。     

一种全光波长路由器的设计及性能分析研究

该文基于一种简单低成本的、波长转换节点共享型全光波长路由器结构,设计了以排队理论为基础的M/M/T/T模型,研究了波长路由器在波分复用波长路由网络中的阻塞特性。数值结果表明,全光网波长路由器的阻塞特性与复用波长数目,链路波长利用率,节点接入光纤端口数,有无波长转换器密切相关。尤其在受限波长转换条件下的配置优化分析,可看出波长路由器无需可调谐器件,也能获得灵活的波长转换能力,不但可避免波长路由器因为精确调谐所开销的时间,而且所有的控制均为简单的开关控制,可降低工程实现的复杂度。     

Minimum connection count wavelength assignment strategy for WDM optical networks

In this paper, we have proposed one wavelength assignment strategy for optical networks which assigns the wavelength according to minimum connection count. The performance of proposed strategy is compared with the most commonly used strategy among the existing strategies in terms of number of searches to find the wavelength for connection establishment. The searching takes the time and directly affects the connection establishment time. The simulation is done using different network models. The results show that the proposed strategy is much better than existing strategy in terms of number of searches required to find a wavelength for establishing the connection and hence connection establishment time reduces.     

Design alternatives for <Emphasis Type="Italic">N</Emphasis>-stage WDM optical planar permutation networks

Planar permutation networks are a class of multistage switching networks with no crossover between paths that interconnect switching elements. A well-known class of planar networks is the N−Stage network that provides a good compromise between the crossbar and the Benes network. In this paper, we address the problem of designing cost-effective N-Stage optical planar networks with space-wavelength switching capability. Such networks are used for switching in communication and computing systems that employ Wavelength Division Multiplexing (WDM) technology. We investigate two classes of space-wavelength N-stage planar networks, and for each class, we design a number of switching networks and analyze their hardware complexity. In addition, we propose a new method for designing a class of space-wavelength planar networks with reduced complexity. It is shown that, for F ≤  W (where F is the total number of fibers and W that of wavelengths) the proposed method results in planar networks with an average of 67% reduction in overall cost compared to that of networks based on fixed-range wavelength converters.     

Study of multicast wavelength arrangement for maximizing network capacity in WDM networks with sparse wavelength converters

The issue of wavelength assignment is one of the most important factors that affect the capacity for the deployment of optical networks. This issue becomes more critical for multicast connections, especially when the network nodes have no wavelength conversion capability. Although the wavelength assignment can be more flexible if each node can perform wavelength conversion, the deployment cost increases accordingly. A compromise is to support a limited portion of conversion nodes in the WDM network. We propose a systematic approach for the wavelength assignment of multicast connections in WDM networks with sparse wavelength conversion nodes. The efficiency of the arrangement of wavelength is measured by its influences on the available capacity of the network and the consumption of wavelengths. By using the proposed approach, the Static Cost Greedy (SCG) algorithm [8] can be easily extended to be applicable in a Sparse Wavelength Conversion Network (SWCN). In addition, instead of SCG, the Minimum-Effect-First (MEF) algorithm is proposed to maximize the network capacity during wavelength assignment. We compare the performance of the proposed MEF methods with the extended SCG scheme through exhaustive simulations. The experimental results indicate that the proposed MEF schemes demonstrate much better performance than the SCG scheme. We also found that the performance is not always improved proportionally to the increment of the wavelength conversion nodes. The improvement reaches saturation when the number of conversion nodes is above 35% of the total number of nodes.

波长交换光网络中路由波长分配技术

路由波长分配问题是在给定连接的情况下,为该请求分配适当的光路进行传输。在无波长转换能力的情况下,需要为光路在其传输的链路上分配相同的波长,这就是波长连续性问题。物理层的光损伤极大的限制了光网络的能力,因此需要可感知损伤的路由波长分配算法来保证传输的质量。对于不同的感知损伤的路由波长分配方式,相应地,有不同的控制平面结构。     

对波分复用系统扩容方式的探索

对在原有8/16×2.5 Gbit/s波分复用系统中增加或替换少量10 Git/s波道的扩容技术作了介绍,如波分复用终端设备改造方案,扩容工程所应用的技术及测试项目等。     

Design of an ultra fast pipelined wavelength scheduler for optical burst switching

Optical Burst Switching (OBS) is an emerging technology that allows variable size data bursts to be transported directly over DWDM links without encountering O/E/O conversion. In OBS, before the transmission of a data burst, a burst header is transmitted through an electronic control path, setting up and tearing down optical paths on-the-fly. Data bursts can remain in the optical domain and pass through the OBS network transparently. Unfortunately, system performance will be greatly degraded, if burst scheduling requests cannot be processed in time. This article quantitatively studied the negative impact of control path overloading on the performance of OBS networks. Results have shown that control path overloading greatly affects the performance of the OBS routers, especially for systems with large WDM channel counts. In order to remove this performance bottleneck, we have designed and implemented an ultra fast pipelined burst scheduler that is able to process a burst request every two clock cycles, regardless of the number of WDM channels per link. The design has been implemented in Verilog HDL and synthesized to FPGAs. Circuit level simulation results confirm the correctness of the design. The circuit has achieved 100 MHz in Altera Cyclone II devices, allowing the scheduler to process a burst request every 20 ns. To the authors’ best knowledge, this is the fastest implementation of burst scheduling algorithms.     

浅析密集波分复用技术及其在CATV中的应用

概述光纤通信中特有的复用技术--波分复用的技术特点,阐明密集波分复用在有线电视网络中的应用及其对开展有线电视业务具有的广阔前景.     

An efficient dynamic distributed optical link establish method in intelligent all-optical networks

In this article, an efficient, fast, and dynamic distributed optical link setup method is proposed. Two kinds of novel optical fast link release mechanisms (Ahead and Timeout Release) are presented for an optical-link establishment. They can dramatically reduce the blocking probability. For dynamic routing detection, a new kind of dynamic weighted Dijkstra algorithm (DW-DA) along with dynamic optical link load balancing is described. A variable mutation and crossover rates of a genetic algorithm (VMCR-GA) is used for fast wavelength assignment with two-novel-wavelength assignment rules in a wavelength relationship graph, which can reduce the necessary wavelengths and link establishment time. Through simulation giving the blocking probability and the time for link establishment on several well-known networks, the effectiveness of this method has been verified. The blocking probability of the network can be reduced significantly below that of normal routing and wavelength assignment (RWA). Furthermore, the calculating time for reaching the minimum blocking probability can be reduced dramatically.