Reconfigurable mesh-based inter-chip optical interconnection network for distributed-memory multiprocessor system

A 4×4 reconfigurable mesh-based inter-chip optical interconnection network is reported for distributed-memory multiprocessor system and the experiment confirmed that the data rate in each channel could reach above 3.125 Gbps, which would be a good solution to solve the communication bottlenecks between processors. Each node of this reconfigurable mesh could realize 15 internal connection patterns to complete the interconnections of processors. Besides, this mesh interconnect network via ultra-high bandwidth waveguides embedded in EOPCB can realize flexible multiprocessor system architecture options.     

Free-space fiber hybrid distributed optical cross-connect interconnect module

We propose implementing a large-scale optical cross-connect network based on a free-space-fiber hybrid interconnect system. The free-space portion of the system is designed to handle shuffle operation of optical beams that need to intersect each other. The fiber portion is used to guide these signals to and from optical transceivers, which can be distributed at different locations. A compact and packaged prototype that handles 256x256 input-output channels is demonstrated.     

Hybrid OCS/OBS interconnect in intra-data-center network

We report on a data center network(DCN) architecture based on hybrid optical circuit switching(OCS) and optical burst switching(OBS) interconnect for dynamic DCN connectivity provisioning. With the combination of the centralized and distributed control of the software-defined optical networks, the proposed interconnect can achieve unprecedented flexibility in dealing with both mice and elephant flow in the DCN. Numerical simulation is employed to investigate the performance of the proposed architecture. The results show that the OBS module has preferable performance in dealing with a larger burst packet, and the throughput is constrained by the capacity of the server random access memory module.     

Application of WDM holographic devices in access and metro networks

In this paper, a design of a generic multipurpose device is described. It can operate, in its basic structure, as a tunable wavelength filter, wavelength multiplexer or λ router; by using a more complex structure, the device works as an optical add drop multiplexer (OADM) or/and optical switch (OS). It can be used in both coarse and dense wavelength division multiplexing technology (CWDM/DWDM) according to the network application. Performance parameters of the device, like switching time, losses, crosstalk or polarization insensitivity are analyzed and compared with other switching technologies. Some applications of the holographic WDM multifunction device in METRO networks are described, such as the utilization of OADMs in optical path protection/reconfiguration between nodes (1 + 1 configuration) and the use of optical switches to interconnect nodes of the METRO–access network with the METRO-Core or long haul networks in a reconfigurable topology. Other applications in Access networks are possible, like the use of the OADMs in optical path protection between the optical line termination (OLT) at the central office (CO) and the remote node (RN) in a fiber to the office passive-optical network (FTTO-PON) or, in some specific cases, the utilization as tuneable holographic filters in a FTTO application, at the Business ONT (BONT), to select the assigned optical wavelength according to the services provided to the customer.     

Effects of germanium incorporation on optical performances of silicon germanium passive devices for group-IV photonic integrated circuits

Optical interconnect in integrated optoelectronic circuits is one of the promising next-generation technologies for replacing metalized interconnect. Efforts have been made to use silicon (Si)-compatible materials such as germanium (Ge) and Ge-buffered III–V compound semiconductors, along with Si, as optical sources for Si and group-IV integrated optoelectronic systems. This opens the possibility that higher fraction of Ge with its high refractive index (n) can be incorporated in Si waveguide for optical interconnect and the graftability between Si and group-IV or III–V materials would be improved in silicon photonics. In this work, advantageous features of nano-structured silicon germanium (Si_1−xGe_x) optical waveguide with different Ge fraction (x) were evaluated by both optical simulations and theoretical calculations, which are mainly found in the enhanced optical confinement and better interfacing capability. Along with the SiGe waveguide, performance of Si_1−xGe_x microring resonator under material loss in the effect of extinction coefficient (k) has been investigated to suggest the necessity of optimizing the Ge content in Si_1−xGe_x passive devices. While carrying out the establish design criteria, n and k have been modelled in closed-form functions of Ge fraction at 1550 nm. Furthermore, by examining high-resolution transmission electron microscopy (HR-TEM) images, process compatibility of Ge with either group-IV alloys or III–V compound semiconductors is confirmed for the monolithically integrated photonic circuits.     

Experimental demonstration of 3×3 10 Gb/s reconfigurable free space optical card-to-card interconnects

In this Letter, we propose and demonstrate the concept of a free space optics-based parallel high-speed reconfigurable card-to-card interconnect architecture employing microelectromechanical systems (MEMS)-based steering mirror arrays in conjunction with VCSEL and photodiode arrays. A bit-error rate of ～10(-6) and a receiver sensitivity below -11.5 dBm are experimentally attained with a proof-of-concept 3×3 10 Gb/s reconfigurable card-to-card optical interconnect demonstrator.     

Tunable 2D time-wavelength optical CDMA encoder for differentiated service provisioning

We propose and demonstrate a reconfigurable tunable encoder for two-dimensional time-wavelength optical code division multiple access (OCDMA). This encoder is capable of creating 2D codes with variable code weight, enabling differentiated service provisioning. The demonstrated novel scheme uses ultra-fast optical delay lines and all-optical sampling while operating at 115 Gchip/s. Our proposed architecture provides an all-optical method of varying the code weight on a bit-per-bit basis, while maintaining the core architecture of a tunable OCDMA encoder.     

AWG and EDFA based optical packet switch using feedback shared loop buffer memory

Optical packet switching provides high speed, data rate/format transparency, efficient use of bandwidth and flexibility. The major problem in the implementation of “all-optical” switching is contention which occurs when two or more packets arrive at the same time for the same destination. To resolve the contention, we have proposed an optical packet switch architecture based on WDM loop buffer memory in the feedback configuration. In that architecture, the contending packets are stored in a loop buffer module, and routed in the free time slots. The buffering duration in the recirculating loop is limited by a circulation limit. The analysis was been done to obtain the maximum number of allowed circulations. This paper proposes improved version of that optical packet switch architecture, to increase the number of maximum allowed circulations. The modification is done either by adding an extra erbium doped fiber amplifier (EDFA) in the original switch or by replacing the core space switch with arrayed waveguide grating (AWG). The performance analysis has been done by the simulations.     

大规模并行处理器阵列中的光纤互连网络

详细介绍了具有６４×６４Ｉ／Ｏ通道的光纤互连网络的设计原理、结构、制作技术和实验结果。此网络应用在两个并行处理器阵列之间，具有可重构功能，实验结果验证了光纤互连的优越性和可行性。     

Prototype Demonstration of Discrete Correlation Processor-2 Based on High-Speed Optical Image Steering for Large-Fan-Out Reconfigurable Optical Interconnections

We present a discrete correlation processor-2 (DCP-2), which is an optical processor with reconfigurability of interconnection patterns for large-fan-out optical interconnection systems. To our knowledge, there is no reconfigurable optical processor satisfying the requirements for large fan-outs such as high-speed reconfiguration of interconnection pattern, high optical efficiency, and high contrast ratio, because existing spatial light modulators (SLM#x0027;s) lack at least one of these features. The DCP-2 architecture fulfills the requirements by using a hybrid configuration composed of a high-speed image steerer and a spatial light modulator, which work in a complementary manner to shorten the setup time of the SLM. We constructed two kinds of prototype demonstrators based on this architecture. In the experiment, reconfiguration speed of the DCP-2 prototype with shift-invariant optical interconnections, in which a liquid crystal SLM cooperated with a two-dimensional acousto-optic beam deflector, was about 26,000 times faster than that of the standalone SLM at the cost of 50#x0025; energy loss by the deflector.     

Analysis of Wavelength-Routed Optical Burst-Switched Network Performance

This paper studies a novel scalable network architecture combining optical burst switching (OBS) with dynamic wavelength allocation to guarantee quality of service (QoS), forming a wavelength-routed optical burst-switched network. All processing and buffering functions are concentrated at the network edge and bursts are assigned to fast tuneable lasers and routed over a bufferless optical transport core using dynamic wavelength assignment. Different burst aggregation mechanisms are evaluated for a range of traffic statistics in terms of delay and packet loss rate. New network performance parameters in an analytical model quantify the advantages of dynamic wavelength allocation. The results define the operational gain achievable with dynamic wavelength assignment compared to quasi-static wavelength routed optical networks.     

一种实现二进制加法符号替换规律的光逻辑系统

为了实现二进制加法符号替换规律,本文提出了一种简单的光逻辑系统,它仅包括一片二维列阵光学双稳器件.本实验采用同时具有NXOR和OR逻辑功能的透反射型ZnS光学双稳干涉滤光片作光逻辑器件.该光学逻辑系统完成了二进制加法四个符号替换规律的并行替换.光学系统采用固定的自由空间互连方法,具有光学硬件少,光功率损耗低,结构简单、实用的优点.     

Optical alignment tolerances in double-side irradiated self-written waveguide-induced fiber arrays packages

In this paper, we present our experimental study on the optical alignment tolerance between the couplings of single-mode fibers (SMFs) connected with a double-side irradiation-induced self-written waveguide (SWW). The study firstly focuses on the coupling of two SMFs and then on the two fiber arrays (FAs) for parallel optical communication. The SWW was formed in dye-dispersed epoxy materials by the photopolymerization technique. Rhodamine 6G dye was dispersed in epoxy, which is commonly used in the photonic packaging industry as a bonding adhesive. Using double-side irradiated SWW, we found the alignment tolerance for such optical interconnect to relax significantly. All the formed SWWs were evaluated in terms of optical loss. In our study, up to 4 µm misalignment tolerance was allowed for only 1 dB loss penalty. In addition, the optical interconnect formed by this technique was also able to tolerate up to ± 10 µm lateral shift with only 1 dB extra loss. The wavelength-dependent loss (from 1520 to 1610 nm) and polarization-dependent loss were less than 0.4 dB. The double-side irradiated SWW-induced couplings between two FAs also provided low optical loss. They were found to be less sensitive to temperature changes, and no significant distortion in the digital signal transmission test was observed. We believe that the findings are useful and applicable to other dye-dispersed epoxy material systems for relaxing the alignment tolerance of the optical interconnects in various photonic packaging situations.     

Analysis of Wavelength-Routed Optical Burst-Switched Network Performance

This paper studies a novel scalable network architecture combining optical burst switching (OBS) with dynamic wavelength allocation to guarantee quality of service (QoS), forming a wavelength-routed optical burst-switched network. All processing and buffering functions are concentrated at the network edge and bursts are assigned to fast tuneable lasers and routed over a bufferless optical transport core using dynamic wavelength assignment. Different burst aggregation mechanisms are evaluated for a range of traffic statistics in terms of delay and packet loss rate. New network performance parameters in an analytical model quantify the advantages of dynamic wavelength allocation. The results define the operational gain achievable with dynamic wavelength assignment compared to quasi-static wavelength routed optical networks.     

研制超宽带全光取样示波器设备

全光取样示波器是研究与开发超高速光通信系统和光子交换网络的关键性测试仪器设备. 本文简介了我们自行设计和研制出的超宽带全光取样示波器设备的实验样机系统, 并报道了我们已取得的初步实验结果. 采用自主研发的高稳定性被动锁模飞秒光纤激光器作为该光学示波器的光脉冲取样源, 我们通过利用高度非线性光纤中的四波混频效应, 成功地实现了对脉宽为1.8ps、重复频率分别为10GHz和40GHz的光脉冲信号的全光取样. 然后通过数字信号处理和计算机图形处理, 得到了再现后的超短光脉冲信号波形, 并测出了其脉冲宽度值为2.3ps. 借助于该光学取样示波器实验样机, 我们还成功地完成了对脉宽为1.8ps、经过伪随机数据序列调制后的10Gbit/s和40Gbit/s光数据信号眼图的精确测量. 这是我国首次报道有关超宽带全光取样示波器设备的实际研制工作及其相应的实验测试结果. 所得到的有关超短光脉冲信号波形的测试结果也与用70GHz宽带电子示波器和超快光电探测器组成的常规光电测量系统所获得的结果进行了比较, 清楚地表明了我们研制出的全光取样示波器实验样机比后者具有更高的时间分辨率和更大的测量带宽.     

光交叉连接节点的功能结构

光交叉连接(OXC)是未来波分复用光传送网实现交换与选路功能的核心部件.目前,OXC节点的物理结构得到深入研究,已经提出了一些采用不同光子器件的OXC实现方案.本文从描述光交叉连接功能的角度出发,给出一种分析OXC节点功能结构的模型,并比较各种OXC方案在功能结构上的差异。     

All optical frequency encoding method for converting a decimal number to its equivalent binary number using tree architecture

In any kind of computing and data processing system the use of binary numbers are found very much suitable and reliable. On the other hand several natural representations have been realized using decimal numbers. So conversion of a decimal number to its binary equivalent and vise-versa are of great importance in the field of computation technology. There lie already a number of established methods regarding such conversion processes. Again optical tree architecture is one of the most promising systems for realizing the optical conversion of any decimal number to its equivalent binary. Here in this communication the authors propose a new method for optical conversion of a decimal number to its binary equivalent using tree architecture based system and frequency encoding principle. In frequency encoding system, frequency of light is used for encoding of decimal digits or binary bits instead of intensity variation. For example 0 and 1 bits of binary number are coded by two different frequencies of light signal, instead of representing the presence of light as 1 and absence by 0. The proposed conversion process has multifaceted advantages in communication, as well as in data processing. To implement the above conversion some characteristic features of semiconductor optical amplifier (SOA) have been used massively. The wavelength conversion property, cross gain modulation and some nonlinear properties of SOA are exploited to get the frequency encoded response. The proposed system carries all the basic advantages of optical processing as well as those of frequency encoding also.     

Polarization-encoded all-optical quaternary multiplexer and demultiplexer - A proposal

Multi-valued logic is positioned as a coming generation technology that can execute arithmetic functions faster and with less interconnect than binary logic. Furthermore, nonbinary data storage would require less physical space than binary data. The application of multi-valued digital signals can provide considerable relief of capacity constraints. In electronics many proposals have already been reported. But, here for the first time we propose an all-optical circuit for designing quaternary (four-valued) multiplexer and demultiplexer with the help of some polarization-encoded basic quaternary logic gates (quaternary min and quaternary delta literal). Nonlinear interferometer-based optical switch can take an important role here. The principles and possibilities of design of all-optical quaternary multi-valued multiplexer and demultiplexer circuits are proposed and described.     

A terabit capacity passive polymer optical backplane based on a novel meshed waveguide architecture

An optical backplane based on a meshed polymer waveguide architecture enabling high-speed board-to-board optical interconnection is presented. This planar array of multimode polymer waveguides can provide passive strictly non-blocking links between server line cards fitted with optical transmitter and receiver arrays. This architecture offers a scalable and low-cost solution to the bandwidth limitations faced by electrical backplanes and is suitable for PCB integration. The reported backplane demonstrator uses a matrix of 100 waveguides each capable of 10 Gb/s operation to interconnect 10 cards for a total capacity of a terabit per second aggregate data rate in multicast mode. Characterisation of the backplane demonstrator reveals low link losses of 2 to 8 dB for a multimode fibre input and crosstalk values below −35 dB. Error free data transmission at 10 Gb/s is achieved with a power penalty of only 0.2 dB at a bit-error-rate of 10⁻⁹. Additionally, lossless operation of a Gigabit Ethernet link over the backplane is achieved even when using the worst-case highest loss links.     

Optical switching and logic gates with hybrid plasmonic-photonic crystal nanobeam cavities

We propose a hybrid resonance architecture in which a plasmonic element is coupled to a silicon-on-insulator photonic crystal nanobeam cavity operating at telecom wavelengths. It benefits from the combined characteristics of the photonic cavity and the plasmonic element, and exploits the unique properties of Fano resonances resulting from interactions between the continuum and the localized cavity states. As confirmed through 3D time-domain simulations, a strong cavity mode damping by the plasmonic element offers mechanisms of controlling a probe signal propagating in the nanobeam. It makes possible to create optical switching devices and logic gates relying on any optical nonlinear effect.