光纤光栅和环行器构成的多路光分插复用器

讨论由光纤光栅和光环行器构成的光分插复用器的结构,性能和特点,提出采用一段刻有多个光纤布拉格光栅的光纤,两个光环行器,WDM复用器和解复用器等器件,构造能够对WDM的多个信道实施分插操作的光分插复用器,该光分插复用器的插入损耗要比简单地把多个单路的光分插复用器进行级联时小得多,波分复用全光网络中的光分插复用技术,是实现波分复用网络的关键技术之一。     

Client-configurable eight-channel optical add/drop multiplexerusing micromachining technology

A client-configurable optical add/drop multiplexer (OADM) is demonstrated using a micromachined 8×6 matrix switch. The matrix switch can be configured to add/drop any of the eight input channels from/to any of the six add/drop ports. For the switching fabric, the insertion loss is 2~3 dB for the dropped channels and 8~9 dB for the added channels by using the backsides of the micromirror switches. The switching extinction ratio is over 40 dB, the crosstalk between channels is less than -40 dB, and they are equipment-limited in this experiment     

利用光纤光栅研制分插复用器

在波分复用的光纤通信系统中,分插复用技术需要低损耗、小型化的、稳定的、可靠的器件。使用光纤光栅,可以 制作多种结构的分插复用器,本文对多种基于光纤光栅的分插复用器的结构和原理进行了研究。     

PLC-based optical add/drop switch with automatic level control

A novel switch configuration for an optical add/drop multiplexer is proposed. By utilizing a certain Mach-Zehnder interferometer both as a component of a double-gate switch and as a level equalizer, we reduced the number of Mach-Zehnder interferometers from five in a conventional switch configuration to three. The add/drop switch simultaneously provides high-isolation switching and polarization-independent automatic level control. The use of planar lightwave circuit (PLC) technology enables this switch to be fabricated with three thermooptic switches (TOSWs) and a monitor tap. High isolation of more than 44 dB and automatic level control accuracy of better than 0.3 dB are achieved. Bit error rate (BER) measurements confirmed switch's usability in the optical add/drop multiplexer     

Performance Comparison of Overlay and Peer Models in IP/MPLS over Optical Networks

We study the connection establishment of label switched paths (LSPs), and compare the LSP blocking performance of the overlay and peer models in IP/MPLS over optical networks. We consider two dynamic routing algorithms for the establishment of LSP connections, of which one is for the overlay model and the other is for the peer model. Our investigations on two typical network topologies, namely NSFNET and ARPA2 networks, show that the number of add/drop ports (or transceivers) on optical cross-connects (OXCs) has a significant impact on the LSP blocking performance for both models. We show by computer simulation that in each case, there is a threshold value for the add/drop ratio, which can achieve almost the best blocking performance. This threshold value remains virtually unchanged as the traffic load varies, but it does depend on the network topology and the number of wavelengths per fiber. This will then indicate the number of add/drop ports to be used so that one can achieve a near optimal blocking performance without incurring unnecessarily excessive network costs. Our investigations reveal that the peer model achieves a much better blocking performance than the overlay model when the number of add/drop ports is relatively high, but that this is not always true when the number of add/drop ports is small.     

Eight-channel bidirectional WDM add/drop multiplexer

The authors propose and demonstrate an eight-channel reconfigurable bidirectional wavelength division multiplexed (WDM) add-drop multiplexer in which all channels can be added/dropped independently in either direction. The performance of the bidirectional WDM add/drop multiplexer is experimentally studied for a data rate of 10 Gbit/s per channel, providing an overall capacity of 80 Gbit/s. It is found that the performance of the add/drop multiplexer is not degraded by a backward propagating signal     

Bi-directional add/drop amplifier module for high-capacity WDM networks

A bi-directional add/drop amplifier (BADA) module with a superior relative intensity noise (RIN) suppression capability has been realised based on a cost-effective dispersion compensation technique. A 14/spl times/10 Gbit/s bi-directional transmission over 200 km-long conventional SMF and channel-by-channel add/drop has been successfully demonstrated. The scalability of the BADA module is analysed.     

Demonstration of RSOA‐Based 20 Gb/s Linear Bus WDM‐PON with Simple Optical Add‐Drop Node Structure

We demonstrate a linear bus wavelength‐reused gigabit wavelength‐division multiplexing passive optical network (WDM‐PON) with multiple optical add‐drop nodes. A commercially available reflective semiconductor optical amplifier‐based WDM‐PON has a sufficient power budget to provide multiple optical add/drop nodes in 16 WDM channels. Sixteen 1.25 Gb/s WDM channels are successfully transmitted over 20 km of single‐mode fiber with four optical add/drop multiplexers, even with 32 dB reflection and chromatic dispersion in the link.     

一种新型的可重构光分插复用器件的设计

设计了一种带四根单模尾纤的光纤准直器,基于这种四光纤准直器及介质薄膜滤波器,提出了一种新型的可重构光分插复用器件的设计方案.该器件只用一个四光纤准直器,输入光纤、输出光纤和分下/插入光纤都分布在器件的同侧,具有体积小、成本低、信道隔离度高等优点.     

Effect of temperature cycling on angular alignment in add/drop filter-module packaging

The thermally-induced, fiber-alignment shifts of ferrule-solder-ferrule (FSF) joints in add/drop filter-module packaging for multiplexer/demultiplexer applications have been studied experimentally and numerically. From experimental measurements of the module-insertion loss difference (0.3 dB) with and without temperature cycling, FSF angular-tilt misalignments of up to 0.05° were found after undergoing 42 temperature cycles. The effects of an imperfect soldering process along the two ferrules during the packaging of an add/drop filter module on the angular-tilt misalignment has been explored in this study. An elastic-plastic finite-element method (FEM) was performed to evaluate the variation of thermal stresses, the distribution of residual stresses, and the angular-tilt misalignment of the FSF joints. Experimental measurements of the FSF angular-tilt misalignment were in good agreement with the FEM calculations. The major angular-tilt misalignments of FSF joints in add/drop filter-module packaging during temperature cycling may come from the localized plastic-solder yielding introduced by the local thermal-stress variation and the redistribution of the residual stresses within the solder. The FSF angular-tilt misalignment and, hence, fiber-alignment shift of the add/drop filter module under temperature-cycling tests can be reduced significantly if a perfect soldering process along the two ferrules can be fabricated.     

A novel bidirectional add/drop amplifier (BADA)

We demonstrate a novel bidirectional add/drop amplifier (BADA) module by using only one N×N arrayed-waveguide grating (AWG). For the effective transmission of bidirectional signals, it is essential to suppress the relative intensity noise caused by Rayleigh backscattering, multiple reflection, and/or AWG crosstalk. The proposed amplifier module can suppress the relative intensity noise simply by using two optical bandpass filters. No degradation was observed in the receiver sensitivity when these amplifier modules were used for the bidirectional transmission and add/drop multiplexing of wavelength-division-multiplexing signals     

DWDM系统光纤光栅分插复用器的设计与实现

综合分析了均匀光纤光栅主反射带内、外反射谱和透射色散特性对DWDM系统光波分插复用的影响，分析计算了DWDM系统中信道参数与光纤光栅参数之间的关系，在此基础上，对用于波分复用系统信道间距分别为50/100GHZ的光波分插复用的光纤光栅进行了设计，并在实验中刻制出相庆的光纤光栅。     

Connection Establishment of Label Switched Paths in IP/MPLS over Optical Networks

We propose and investigate three connection admission control policies for the establishment of label switched paths (LSPs) in IP/MPLS over optical networks. We show that the policy of establishing LSPs first in the optical layer achieves a better blocking performance. We examine the effect of the number of add/drop ports of optical cross-connects (OXCs) on the LSP blocking performance. We show that there exists a lower bound for the number of add/drop ports of OXCs for the network to achieve almost the best LSP blocking performance.     

一种基于光纤Bragg光栅的全光纤分/插复用器

研制了用于ＷＤＭ全光网的全光纤型分／插复用器,由两个相同的光纤环行器和串接其间的光纤Ｂｒａｇｇ光栅组成。其中光纤Ｂｒａｇｇ光栅是用紫外光直写方式在普通单模光纤上制成。文中给出了该复用器的上／下路端口隔离度和信道插入抽耗等主要测量结果。其特点是结构简单,可实现信道波长再利用,从而提高网络的灵活性。     

双芯片张光分插复用器的理论分析和设计

本文介绍了双芯光纤光分插复用器的工作原理、结构和功能,并利用耦合模理论分析了器件的工作特性,讨论了各部分参数对上／下路特性的影响。结果表明,为同时实现上路和下路功能,应尽可能使用强光纤光栅以缩短光纤的长度并同时维持高反射效率。     

Wavelength-tunable add/drop optical filter

A new type of add/drop optical filter discretely tunable along equally spaced channels is presented. This device may have very useful applications in WDM optical networks.     

Ion-exchanged waveguide add/drop filter

An add/drop filter is fabricated using ion-exchanged waveguides and photowritten Bragg gratings. The device exhibits 20 dB extinction ratios and 3 dB bandwidths of 0.4 nm (100 GHz)     

MOSAIC: a multiwavelength optical subcarrier multiplexed controllednetwork

The experimental demonstration of MOSAIC, a reconfigurable WDM add/drop network with subcarrier multiplexed control, is presented. The MOSAIC network implements the optical layer protocol to support bit-rate transparent multichannel lightpaths. Two types of add/drop multiplexers are implemented and combined in a three-node experiment. Multihop lightpaths are established giving an end-to-end bit error rate of better than 10^-9 at 1.2 Gbps. The reconfigurable add/drop multiplexer is based on a novel dilated 2×2 acoustooptic filter switch crossconnect and an analog optoelectronic crossconnect that drives a ten-wavelength laser array transmitter up to 2.5 Gbps per wavelength. The fixed wavelength add/drop multiplexer utilizes a fast digitally tunable laser transmitter. Both add/drop multiplexers support bit-rate transparent 2R optoelectronic regeneration as well as wavelength translation. Subcarrier multiplexing on each wavelength is used to support channel state monitoring and channel equalization as well as transmission of digital network control information. Systems experiments demonstrate cascaded 2R optoelectronic regeneration with wavelength translation and cascaded multichannel optical switching with up to seven hops. It is shown that combining cascaded 2R optoelectronic regeneration with cascaded multichannel optical switching can be used to balance jitter accumulation and amplified spontaneous emission generated amplitude noise to yield high signal-to-noise ratio for lightpaths     

光分插复用器及应用

综述了各种不同类型的光分插复用器的工作原理和最新发展,并对其性能与应用前景作了评述。     

Self-Clocked All-Optical Add/Drop Multiplexer for Asynchronous CDMA Ring Networks

In this paper, we demonstrate a novel self-clocked code-drop unit for incoherent optical code-division multiple-access (CDMA) networks. The unit is based on an all-optical thresholder with internal wavelength conversion that creates a control signal for the drop gate from the incoming data stream. This architecture does not require an external clock signal for drop operation and can be used in asynchronous ring networks. The proposed unit is experimentally demonstrated for two-dimensional time-wavelength optical CDMA codes at a bit rate of 2.5 Gbit/s with two different types of drop gates: terahertz optical asymmetric multiplexer and nonlinear fiber-based loop mirror. Error-free operation is achieved in both configurations. The development of a self-clocked add/drop multiplexer demonstrates a novel concept of asynchronous node operation in multiple access networks.