Fused biconical tapered fiber-optic devices: Application to data buses

Abstract

The technology of fiber-optic couplers based on fused biconical tapered structures is reviewed, and the linear and star data-bus configurations that can be constructed using these couplers are discussed. A useful network topology for interconnecting star couplers using the hybrid transmission-reflection star coupler is also proposed. This network configuration has the advantage of requiring significantly less optical fiber than networks employing a single transmission or reflection star.     

A reliable wavelength division multiplexing metro-access network realizing crosstalk-free transmission between uplink and downlink

A novel wavelength division multiplexing metro-access network based on dual-fiber ring of remote nodes and star topology of optical network units is designed to realize the reliable network in case of either single or dual fiber failure. In the design, the survivability of the network is largely enhanced by three work modes. Simultaneously, this network structure can also avoid the crosstalk between uplink and downlink. The simulation results demonstrated with 2.5-Gb/s up/downstream signals show this approach could work very well.     

Smart City Surveillance Through Low-Cost Fiber Sensors in Metropolitan Optical Networks

Abstract

A continuously growing number of municipalities has optical fiber networks supporting communications at their disposal. These fiber installations can also be utilized to convey low data optical signals from a large number of deployed sensing elements, usually positioned in critical infrastructure locations, providing a variety of useful information. Such information can be used in the context of a “smart city” to provide citizens with higher-level services or even to proactively ensure public security and safety. This work demonstrates a fiber sensing network based on low-cost fiber Bragg grating sensors that are able to appropriately oversee diverse monitoring parameters.     

Driving Innovation in Optical Networking: 30 Years of Research and Development Results from Circuit to Packet Transport

Abstract

Over the past 30 years, network applications have changed with the advent of innovative services spanning from high-speed broadband access to mobile data communications and to video signal distribution. To support this service evolution, optical transport infrastructures have changed their role. Innovations in optical networking have not only allowed the pure “bandwidth per fiber” increase, but also the realization of highly dependable and easy-to-manage networks. This article analyzes the innovations that have characterized the optical networking solutions from different perspectives, with a specific focus on the advancements introduced by Alcatel-Lucent's research and development laboratories located in Italy. The advancements of optical networking will be explored and discussed through Alcatel-Lucent's optical products to contextualize each innovation with the market evolution.     

L-Band Multi-Wavelength Brillouin–Raman Fiber Laser with 20-GHz Channel Spacing

Abstract

A tunable multi-wavelength L-band Brillouin–Raman fiber laser with a 20-GHz channel spacing utilizing bidirectional ring cavity is proposed and experimentally investigated. The laser employs a co-pumped dispersion compensating fiber as a gain medium for both Brillouin and Raman gains. With a Raman pump of 425 mW, the laser system can generate up to 12 double-spaced Brillouin Stokes signals. This simple laser configuration provides stable Brillouin Stokes signals in the absence of self-lasing cavity modes with a tuning range exceeding 35 nm without using any filtering mechanism. The Stokes signals have more than 20 dB of optical signal-to-noise ratio.     

Investigation of wavelength division multiplexed hybrid ring-tree-star network topology to enhance the system capacity

In this paper, we have investigated wavelength division multiplexed (WDM) hybrid (ring-tree-star) topology. Eight optical add/drop multiplexers (OADMs) are used to make ring structure. The single mode fiber and dispersion compensating fiber and semiconductor optical amplifier (SOA) are employed between each OADM to achieve a maximum. To increase the number of users each OADM node of ring network is connected to star and tree network topology which can accommodate more than 2048 users. Various system parameters (for different channel spacing, different input power signal, different data rates and the fiber length) are varied to investigate the system performance in the term of BER and Q factor.     

Bidirectional Wavelength Reconfigurable Module Based on Tunable Fiber Bragg Grating and Remote Pump Amplifier

Abstract

This article presents a novel bidirectional wavelength reconfigurable optical network utilizing a remotely pumped erbium-doped fiber amplifier and tunable fiber Bragg gratings. The system is experimentally demonstrated at a 10-Gb/s per channel over 20-km fiber span that verifies the metro-network range system performance. The achieved power penalty is less than 1 dB when compared to the back-to-back transmission link. An example of practical application where the proposed module is used as an add/drop multiplexer and a remote node in the bidirectional wavelength division multiplexing passive optical network system is described.     

Application of the steiner street problem to a more economical data bus

Abstract

A data bus consists of the interconnection of N terminals, each of which is connected to every other terminal. There are three fundamental approaches to the topology of the network: (1) the tee network, for which the connecting nodes coincide with the communicating nodes; (2) the star network, for which there is only one connection node, which may not coincide with a communication node; and (3) the Steiner minimal tree network, for which there can be many nodes, each of which is difficult to locate in the x-y plane. The tee and star approaches are receiving most attention but the third is the only one that economizes on the use of cable (glass fiber waveguide). After a discussion of the tee and star networks, we turn to the Steiner minimal tree network and a method of locating the connecting nodes so that the total amount of cable is minimized.     

Beyond 90-km Reach of a 16 × 2.5 Gb/s C/L-band Dense Wavelength-Division Multiplexing Metropolitan Network Based on Self-Seeded Reflective Semiconductor Optical Amplifiers

Abstract

This article reports the operation of a cost-effective, colorless, dense wavelength-division multiplexing metropolitan network based on self-seeded reflective semiconductor optical amplifiers. All reflective semiconductor optical amplifiers used in the experiments are packaged in commercial small form-factor pluggable modules. The proposal architecture is simple and symmetric thanks to utilization of two cyclic array waveguide gratings. Downstream link functions in the C-band wavelength range and the upstream link functions in the L-band wavelength range. By using erbium-doped fiber amplifiers to extend the reach, an error-free transmission over 90 km for 16 channels at 2.5 Gb/s was experimentally demonstrated for both directions, and an optical budget over 35 dB was obtained.     

平面波导型对称星型耦合器的优化设计

通过有限差分波束传播法(FD-BPM)研究了N×N平面波导型星型耦合器的优化设计思想和方法,并通过17×17星型耦合器的模拟设计证明了它的可行性.给出了在输出端引入辅助波导的方法,以提高输出波导阵列的均匀性.并通过模拟计算,分析了圆心缩入程度和锥形区的形状对输出结果的影响.此法也同样适合于N值更大的星型耦合器.     

4 × 4 Plastic Optical Fiber Star Coupler Incorporated with a Common Polymer Waveguide Optical Power Distribution Region

Abstract

Two types of 4 × 4 plastic optical fiber star couplers incorporated with a polymer waveguide as the optical power distributor are proposed, and their high performances are demonstrated. The characteristics of the proposed star coupler are investigated based on ray optics, and its power distribution performance is evaluated in terms of the flatness of the coupling ratio and the amount of the excess loss. Under the best conditions, the flatness of the coupling ratio and the excess loss of the fabricated device have been obtained as 2.0 dB and 2.5 dB, respectively.     

Ultra-High-Capacity Passive Optical Network Systems with Free-Space Optical Communications

Abstract

This article experimentally demonstrates a hybrid fiber–free-space passive optical network that enables high spectral density, aggregated capacity, and total throughput through ultra-dense wavelength-division multiplexing baseband and radio-over-fiber channels. Ultra-dense wavelength-division multiplexing 10-Gb/s Nyquist-shaped 16-ary quadrature amplitude modulation, 10-Gb/s radio-over-fiber orthogonal frequency-division multiplexing, and 8.75-Gb/s baseband orthogonal frequency-division multiplexing signals per user were transmitted through a maximum 40-km passive optical network, which includes a 6-m free-space optics link with acceptable performance.     

Multi-purpose nonlinear optical microscope. Its principle and applications to polar thin-film observation

Multi-purpose nonlinear optical microscope is an optical microscope which images 2D distribution of the optical second harmonic (SH) waves from a specimen. Image contrast can be obtained either by inhomogeneous distribution of nonlinear optical tensor components or by the interference between SH waves from a specimen and a standard plate. This microscope also functions as a fluorescence (FL) microscope, and SH and FL images can be obtained from the same part of a specimen. Absorption and FL spectra from a specific part of a specimen are measured through an optical fiber which connects an ocular with a polychromator. These functions are especially useful for investigation of the J-aggregate state of polar dye molecules. Several photographs taken by the microscope revealed the structure of merocyanine dye/arachidic acid mixed monolayer and the role of bridge ions in the subphase. Fiz. Tverd. Tela (St. Petersburg) 41, 764–769 (May 1999) Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor.     

Full-Duplex Link Providing Alternative Wired and Wireless Broadband Access for the Wavelength-Division Multiplexing Passive Optical Network with a Uniform Converged Signal Format

Abstract

A full-duplex link implementing alternative wired and wireless access for wavelength-division multiplexing passive optical network is proposed with the uniformed three-tone converged optical signal, which provides a wired or wireless downlink access signal alternatively and an uplink optical carrier. The uplink optical carrier reversed by the converged optical signal makes the hybrid optical node unit free from the optical source. The simulation results show that the full-duplex link with a 10-Gb/s 16-quadrature amplitude modulation (16-QAM) downstream and 5 Gb/s binary upstream can provide both wired access with a bit-error rate below 10^?9 and radio-over-fiber-based wireless access with a bit-error rate below 10^?7 over 40 km of fiber without an optical source and optical amplifier in the hybrid optical node unit.     

A Survivable Wavelength Division Multiplexing Passive Optical Network with Both Point-to-Point Service and Broadcast Service Delivery

Abstract

A survivable wavelength division multiplexing passive optical network enabling both point-to-point service and broadcast service is presented and demonstrated. This architecture provides an automatic traffic recovery against feeder and distribution fiber link failure, respectively. In addition, it also simplifies the protection design for multiple services transmission in wavelength division multiplexing passive optical networks.     

军用车载光纤数据总线的拓扑研究

研究和量化了拓扑和访问耦合器对光纤网络物理性能的影响。针对双总线形、星形、环形和双环形四种光纤网络拓扑,比较它们的光纤需求长度、平均传播延迟、传输衰减、最大比特率及容错。结果表明:在100个节点情况下,星形拓扑需要的光纤长度是双环形的3.8倍,而双环形的平均传播延迟是星形的3.3倍;双总线形的传输衰减最大,在10个节点情况下,要求接收器的动态灵敏度达24dB;假设使用垂直腔面激光器和渐变折射率多模光纤,使用容错耦合器导致最大比特率性能降低,双总线形和星形的最大比特率与节点数相关。这些结果可为选择光纤数据总线拓扑和访问耦合器提供参考。     

Numerical Investigation on Performance of In-Building Plastic Optical Fiber Transmission Systems and Role of Digital Television Broadcasting

Abstract

This article reports a numerical investigation on the transmission performance of multilevel systems operating in building links encompassing step-index plastic optical fibers. For such an aim, a simplified model for the multimode fiber propagation is introduced. A sub-carrier multiplexing technique is also simulated to demonstrate the distribution of broadcasting television channels by adopting such fibers. The reported results show that a unique building network based on step-index plastic optical fibers is suitable to carry both Ethernet and broadcast TV signals in all rooms.     

Alternative Wired and 60-GHz Wireless Full Duplex Access Based on a Polarization Orthogonal Dual-Tone Optical Millimeter-Wave Signal

Abstract

A novel full duplex fiber wireless link providing alternative wired and 60-GHz wireless access is proposed based on a polarization orthogonal dual-tone optical millimeter-wave signal. In a hybrid optical network unit, the downlink optical signal can be decomposed as a single-sideband optical millimeter-wave signal (baseband optical signal) for wireless (wired) access by a polarization controller and polarization beam splitter. The uplink optical carrier abstracted from the downlink optical signal makes the hybrid optical network unit free from the optical source. The simulation results show that both downlinks and uplinks for either wired or wireless access can maintain quite good performance over 60 km of fiber.     

基于光纤光栅波长路由的光纤自愈网

介绍了一种基于光纤光栅波长路由的全光双纤单向自愈环网,环内四节点具有16×10Gbit/s的传输能力。利用啁啾光纤光栅(CFBG)的波长可选择特性,实现了分布式的上下话路和波长选择功能,同时有效地补偿了传输色散。网络管理参照了网络管理协议(SNMP)的网络管理模型,通过对网络的重要参数进行实时监测来控制网络运行。实验结果表明,当环上任一处光缆发生故障时,通信业务能够自动恢复,恢复时间小于50ms,可实现网络的快速自愈,符合ITU-T G.841的建议规定。     

基于DMD光谱可调的星模拟器光源光学系统设计

为满足在各种谱线分布下对星敏感器探测能力的高准确度标定,提出了一种基于数字微镜器件的光谱可调星模拟器光源光学系统设计方法,以解决星模拟器与星敏感器观星色温不匹配对星敏感器光信号定标准确度产生的问题.首先,根据设计指标选取Czerny-Turner型光学系统为光源光学系统,对Czerny-Turner型光学系统的彗差和象散进行分析,选取消彗差的Czerny-Turner结构;其次利用MATLAB程序求解Czerny-Turner型光学系统初始结构并应用ZEMAX对其进行优化;最后对光学系统进行公差分析.公差分析结果表明,在400~1 100nm的工作谱段范围内,光学系统的光谱分辨率小于2nm,设计结果满足要求,有效降低了光谱不匹配带来的定标误差.