All-optical ASK/DPSK label-swapping and buffering using Fabry-Perot laser diodes

We describe an approach for optical label encoding that allows the realization of all-optical label-swapping in optical packet-switched networks. The proposed method is based on a combination of the amplitude-shift-keying (ASK) modulated payload with the differential phase-shift keying (DPSK) modulated label on the same optical carrier. We demonstrate an implementation using dual-wavelength injection locking (DWIL) of a Fabry-Perot laser diode. Bit-error-rate measurements were performed for the 10-Gb/s payload, and the 2.5-Gb/s label showed the feasibility of the proposed method. An all-optical buffer for the two-level ASK/DPSK optically labeled packets is also described. The buffer is implemented by routing the packet via a delay line if potential contention is predicted. Error-free operation was also achieved.     

Ultrafast All-Optical Serial-to-Parallel Converters Based on Spin-Polarized Surface-Normal Optical Switches

We describe our recent work on all-optical serial-to-parallel converters (SPCs), from the all-optical switches employed in the SPCs to the application of the SPCs for packet processing. The ability to handle ultrafast optical signals is enabled by types of surface-normal optical switches employing different switching mechanisms: one is based on rapid electron trapping in low-temperature-grown Be-doped quantum wells, and the other is based on differential spin-excitation. With these switches, 1:16 SPCs are demonstrated for 40-Gbit/s, 100-Gbit/s, and 1-Tbit/s optical packets. In addition, the SPC is compact, low power, polarization insensitive, exhibits extremely high on/off ratios, and generates a simultaneous parallel output, and thus, provides a promising interface device allowing the processing of ultrafast, asynchronous optical packets in a highly functional complementary metal-oxide-semiconductor (CMOS) processor. As an application, an optical label swapper that integrates the SPC with a CMOS processor is also demonstrated for 40-Gbit/s asynchronous optical packets     

All-optical label processing techniques for pure DPSK optical packets

We present two all-optical label processing schemes for pure differential phase shift keying packets. The two techniques are based on the already used optical correlators and on a novel time-to-wavelength conversion of the label information. They require that the label information is encoded by using pulse position modulation, which makes the label processor simpler and can allow very fast processing speed. We investigate and compare the efficiency in terms of packet overhead of pulse position modulation coded labels with ordinary binary coding and show that pulse position modulation is still attractive for medium-size network and for system implementing optical label swapping. We then experimentally demonstrate that the two techniques can distinguish several labels at distinct outputs. Both operate at low optical power, asynchronously, and could allow for photonic integration. Scalability and processing speeds of the two systems are discussed. We also show that the two label processors can be used to implement an optical label swapping system. Experimental results show that the two labels are distinguished at two distinct ports and erased from the incoming packet, so that a new label can be inserted. Scalability and processing speed are discussed as well.     

一种新型光标记交换技术

光交换技术是光网络中的一项重要技术。文章介绍了一种新的光标记交换技术,利用光载波的抑制来产生光标记和载荷,并对新旧标记替换方法进行了对比,采用新技术所产生的标记和载荷具有很高的消光比,相互之间没有串扰,在接收端容易分离,且标记和载荷部分可以具有不同码型和协议,灵活性更强。     

Monolithic Wavelength Converters for High-Speed Packet-Switched Optical Networks

This paper describes the design and demonstration of advanced 40-Gb/s return-to-zero (RZ) tunable all-optical wavelength converter technologies for use in packet-switched optical networks. The device designs are based on monolithic integration of a delayed interference Mach-Zehnder interferometer (MZI) semiconductor optical amplifier (SOA) wavelength converter with a sampled-grating distributed Bragg reflector tunable laser and an on-chip waveguide delay. Experimental results are presented demonstrating error-free wavelength conversion with 1-dB power penalty at 40-Gb/s data rates. By incorporating label modulation functionality on-chip along with a fast tunable 40-Gb/s wavelength converter, fully monolithic packet-forwarding chips are realized that are capable of simultaneous error-free wavelength conversion of 40-Gb/s payloads, remodulation of 10-Gb/s packet headers, and data routing through fast wavelength switching     

Introduction to the Special Issue on Nonlinear-Optical Signal Processing

The 11 invited and 37 contributed papers in this special issue focus on nonlinear-optical signal processing. Topics covered include: nonlinear pulse shaping; 2R and 3R regeneration; all-optical clock recovery; optical limiting; optical bistability; all-optical switching/gating; optical data format conversion; wavelength conversion; phase conjugation; phase-sensitive amplification; optical delay lines; optical burst/packet switching; all-optical OTDM multiplexing/demultiplexing; and micro- and nano-scale nonlinear-optical devices.     

Highly Stable 160-Gb/s OTDM Technologies Based on Integrated MUX/DEMUX and Drift-Free PLL-Type Clock Recovery

This paper reports 160-Gb/s optical time-division-multiplexed (OTDM) technologies including an all-optical integrated multiplexer (MUX) providing all-channel independent modulation, an all-optical integrated demultiplexer (DEMUX) that offers all-channel simultaneous demultiplexing, and a drift-free phase-locked-loop (PLL)-type clock recovery circuit for ultrahigh-speed OTDM signals. We present the configuration of each technology and the results of experiments on those technologies. Highly stable operation is successfully demonstrated by using a MUX based on periodically-poled lithium niobate (PPLN) hybrid integrated planer lightwave circuit (PLC), a DEMUX based on semiconductor optical amplifier hybrid integrated PLC, and clock recovery circuit based on a PLL with an optical phase modulator and a PPLN waveguide     

一种新的智能变电站通信业务安全隔离技术的研究

为了保障智能变电站通信网络的可靠性和安全性,必须对网络中的通信业务流进行安全隔离传输。分析了智能变电站通信业务流的特点,简述了目前常用的网络隔离技术,着重剖析了目前智能变电站通信网络采用的业务隔离技术的应用情况和特点,指出智能变电站通信业务流对安全隔离的迫切需求。研究了全光交换技术的分类和主流技术的主要特性指标,探索性地提出基于全光波长和全光标签混合交换技术的电力业务安全隔离方案,并详细介绍了方案的技术原理和实现措施。通过引入业务隔离评估模型,以实验方式论证了该方案的可行性。     

基于快速响应任务的有效载荷电子系统结构

有效载荷控制器、中央处理器以及存储单元（PCPMU）通过利用高度集成的多功能部件以及标准接口组成一个模块化结构.该结构为有效载荷电子系统（PE）组装、测试和集成提供了可扩展的多任务能力,引起复杂性、质量和体积的下降,以及相应可靠性的提高,使低成本快速响应任务成为可能.首先阐述了PCPMU的体系结构,比较了在光学、合成孔径雷达（SAR）和通信任务上的应用.然后介绍了PCPMU的部件选择要求,提出了机械封装方法.最后通过与传统方式对比总结了PCPMU的优点及影响.     

Benefit of SPM-based all-optical reshaper in receiver for long-haul DWDM transmission systems

The effectiveness of a self-phase modulation (SPM)-based all-optical reshaper with optically time-division-demultiplexing receiver was experimentally investigated using 42.7-Gb/s carrier-suppressed return-to-zero (CS-RZ) signals. We have confirmed that this scheme is quite effective to suppress the waveform degradation due to optical signal bandlimitation. We have demonstrated 80% spectral efficiency without using polarization demultiplexing by using the all-optical reshaper. We have also demonstrated 50-GHz-spaced 55/spl times/42.7 Gb/s signals transmission over 2500 km, using an optically bandlimited CS-RZ signal and the SPM-based all-optical reshaper in receiver without using polarization demultiplexing. A Q-factor improvement of about 1.5 dB was obtained by using the all-optical reshaper.     

A simple all-optical light switch and its relations to opticalcomputing: a demonstration for teaching photonics

The authors discuss how a simple and inexpensive all-optical light switch can be built for teaching and demonstrating photonics in a classroom or for undergraduate lab experiments. The discussion of this readily understandable device will familiarize the student with the similarities and differences between photonics and electronics. As an example, the authors consider how this device relates to all-optical computing circuits, promoting a comparison between electronic and optical integrated circuits     

Optical burst switching for the next generation Internet

Demands for network bandwidth increase daily. In order to meet our ever-increasing network bandwidth needs, one solution is to design and build the next generation Internet with an optical core infrastructure, with last connection provisioning time and unprecedented high data rates of 100 terabits per second and higher. An optical network is built by interconnecting various optical switches with wavelength-division multiplexing (WDM) fibers, i.e., fibers that can simultaneously transmit data over different wavelengths. Many of today's commercial optical networks, however, do not utilize the WDM technology efficiently. With respect to the current state of the technology, an Optical Burst Switched (OBS) Network is one of the most promising all-optical architectures for the next generation Internet. It efficiently supports the transmission of bursty traffic over an all-optical infrastructure. OBS is still being developed and it has not been standardized yet. This article describes the main features of an OBS network, its benefits as well as its challenges.     

All-Optical Modulation in a Silicon Waveguide Based on a Single-Photon Process

All-optical, low-power modulation is a major goal in photonics. Because of their high mode-field concentration and ease of manufacturing, nanoscale silicon waveguides offer an intriguing platform for photonics. So far, all-optical modulators built with silicon photonic circuits have relied on either two-photon absorption or the Kerr effect. Both effects are weak in silicon, and require extremely high (~5 W) peak optical power levels to achieve modulation. Here, we describe an all-optical Mach-Zehnder modulator based on a single-photon absorption (SPA) process, fabricated entirely in silicon. Our SPA modulator is based on a process by which a single photon at 1.55 mum is absorbed and an apparently free-carrier-mediated process causes an index shift in silicon, even though the photon energy does not exceed that of silicon's bandgap. We demonstrate all-optical modulation with a gate response of 1deg/mW at 0.5 Gb/s. This is over an order of magnitude more responsive than typical previously demonstrated devices. Even without resonant enhancement, further engineering may enable all optical modulation with less than 10 mW of gate power required for complete extinction, and speeds of 5 Gb/s or higher.     

All-optical logic gates by using multibranch waveguide structure with localized optical nonlinearity

We propose all-optical logic gates by using a multibranch waveguide structure with localized optical nonlinearity. By simply setting nonlinear media in the selected output guides and properly launching the input power, the numerical results show that the proposed all-optical waveguide structure could really function as AND and OR logic gates.     

All-optical Multiplication with the help of Semiconductor Optical Amplifier—assisted Sagnac Switch

An all-optical two 2-bit numbers multiplication with the help of Semiconductor Optical Amplifier (SOA)—assisted Sagnac Switch is proposed and described. The paper describes the multiplication using a set of all-optical half-adder and AND gate. Because of the lack of fast, accurate, and large dynamic range analog-to-digital converter, optical implementation of the digital multiplication through analog convolution algorithm yields a slow digital multiplier. By using a set of optical half-adder and optical AND, a new optical fast digital multiplication method is proposed. The new method promises both higher processing speed and accuracy. Numerical simulation result confirming described methods and conclusion are given in this paper.     

Field demonstration of in-line all-optical wavelength conversion in a WDM dispersion managed 40-Gbit/s link

The development of wavelength-division multiplexing (WDM) all-optical transport networks is an interesting solution to increase the capacity of long-haul transmission systems and to solve the route-exhaust problems of metropolitan networks, driving down the cost of that traffic. Routing can be achieved using a transparent device able to select and interchange wavelengths, such as an all-optical wavelength converter. In this paper, an optical transport network over an embedded link located between Rome and Pomezia in Italy is emulated. The transmission has been realized along a WDM, 5/spl times/100 km long, dispersion managed link at 40 Gb/s. The in-line rerouting process has been controlled by means of an all-optical wavelength converter realized with a periodically poled lithium niobate waveguide. Moreover, a polarization-independent scheme for the converter has been exploited to allow the in-line signal processing. This scheme is based on the counterpropagation of TE and TM signal components along the same guide and results extremely compact. In this paper it is demonstrated that wavelength conversion and rerouting add no penalty with respect to the simple transmission along the embedded cable. This result seems to be another step toward the feasibility of true all-optical networks.     

非线性光环镜在电力通信中的应用思考

因为具有独特的优点,非线性光环镜(NOLM)是光通信系统中非常重要的器件。本文阐述了非线性光环镜的基本原理,主要介绍了应用NOLM作为光判决单元、全光2R中继器以及脉冲整形器等在电力高速光通信系统中潜在的应用,分别研究了它们的原理、特点及发展状况。     

光开关及其转换时间测量

光开关在未来全光网中发挥着重要作用.准确测量光开关的转换时间为其应用在不同领域提供了参考.所制作一套光开关转换时间分析仪,已用在试验和教学中.     

All-Optical Tb/S 3R Wavelength Conversion Using Dispersion-Managed Light Bullets

We present an all-optical wavelength converter that can operate at a very-high-switching rate with simultaneous reshaping, retiming, and regenerating (3R) capabilities based on nonlinear interactions between dispersion-managed (DM) (3+1)-dimensional optical solitons (light bullets). Numerical simulations have been performed to demonstrate the generation of the DM light bullets and the spatial dragging interaction between solitons with different colors for ultrafast wavelength conversion application. This all-optical 3R wavelength converter has a very compact size of 100 mum times 100 mum times 1 mm, and is able to convert information at an ultrahigh speed of over 1 Tb/s between wavelength channels of 50 nm apart. Such an ultrafast all-optical wavelength converter has potential applications in future optical time-division multiplexing (OTDM) and wavelength-division multiplexing (WDM) combined communication networks that require both the ultrafast switching speed due to the large bandwidth within each wavelength channel and the wavelength conversion function for exchanging information between different wavelength bands or spatial switching within the same wavelength bands.     

Recent Advances in Optical Processing Techniques Using Highly Nonlinear Bismuth Oxide Fiber

We report our recent studies on nonlinear processing of optical signals using a 35-cm highly nonlinear bismuth oxide fiber (Bi-NLF). Our findings are based on self-phase modulation, cross-phase modulation, and four-wave mixing in the Bi-NLF. We demonstrate applications of the nonlinear techniques in optical signal regeneration, tunable optical delay, stabilization of multiwavelength laser source, tunable optical pulse generation, microwave photonic carrier frequency multiplication, and all-optical wavelength conversion.