An optical holographic backplane interconnect system

An optical holographic backplane interconnect system capable of high-speed information transmission between optoelectronic transmitter/receiver boards is described. Using conjugate pairs of transmission gratings in a folded reflection geometry, a practical method of insulating the interconnect system from wavelength variations due to temperature or power fluctuations can be achieved. The final demonstration unit was developed in a fully packaged form and has the potential for reconfigurable interconnects and may serve as a testbed for a variety of interconnect networks and hardware protocols     

光互联背板研究现状

随着高性能计算和高速通信等技术的飞速发展,信息量呈指数暴增,对高速背板带宽、速率、互联密度及制造工艺等要求越来越高。光互联背板具有高速率、高带宽、低功耗、低损耗和抗电磁干扰等优势,可有效解决电互联高速背板的技术瓶颈。本文对光互联背板制造技术的研究现状进行了阐述与分析,探讨了光互联背板的关键技术及未来发展方向。     

Optical digital cross-connect system using photonic switch matricesand optical amplifiers

This paper presents, for potential application to network failure restoration, an optical digital cross-connect system (DCS) which uses both a photonic switching network and an electric DCS. It is shown that a system constructed of LiNbO₃ 8×8 switch matrices and semiconductor traveling-wave optical amplifiers (TWA's) could be applied to metropolitan area networks. An experimental optical DCS system has been designed and fabricated which incorporates both LiNbO₃ switch matrices and TWA's, and with it, line-failure restoration, a fundamental operation of optical DCS, has been successfully demonstrated     

Optical beamsteering using integrated optical modulators

A device has been designed and fabricated to demonstrate the principle of using the interference pattern of a number of coherent optical sources to form and steer an optical beam. Steering of the beam can be accomplished by varying the relative phase of the constituent sources. The effect of relative source phase variation and source separation variation has beers considered and optimized using a multiple source interference model. In this case the constituent sources are the outputs of integrated optical waveguides, excited by a common optical source to maintain relative coherence. In order to demonstrate the principle of beamsteering, a device with two constituent sources (waveguides) has been fabricated, and the resultant output interference pattern has been laterally translated by varying the phase of the output of one waveguide with respect to the other, via a novel optical phase modulator     

Optical parallel logic gates using a shadow-casting system for optical digital computing

A new, simple method of optically implementing optical parallel logic gates has been described. Optical parallel logic gates can be implemented by using a lensless shadow-casting system with a light-emitting diode (LED) array as a light source. Pattern logic, i.e., parallel logic for two binary patterns (variables), is simply obtained with these gates; this logic describes a complete set of logical operations on a large array of binary variables in parallel. Coding methods for input images are considered. Applications of the method for a parallel shift operation and optical digital image processing, processing of gray-level images, and parallel operations of addition and subtraction for two binary variables are presented. Comparison of the operation of the proposed optical logic gate with that of array logic in digital electronics leads to a design concept for an optical parallel array logic system available for optical parallel digital computing.     

High-speed electrical backplane transmission using duobinary signaling

High-speed electrical data transmission through low-cost backplanes is a particularly challenging problem. We present for the first time a very effective approach that uses the concept of duobinary signaling to accomplish this task. Using a finite-impulse-response filter, we are able to compensate for the phase and amplitude response of the backplane such that the resulting frequency response of the channel is that of an ideal duobinary filter. At the output of the backplane, we use an innovative pseudodigital circuit to convert the electrical duobinary to binary. For 10-Gb/s data transmission, we demonstrate a bit error rate <10/sup -13/ through electrical backplane traces up to 34 in in length on FR4. A full discussion of the concept, system architecture, and measured results are presented. Analysis is presented that compares and contrasts this approach to PAM-4 and standard nonreturn-to-zero signaling.     

A method for rebroadcasting signals in an optical backplane bussystem

A guided-wave optical backplane bus system intended for use in high-performance board-to-board interconnects is described. Its multiplexed polymeric holograms can implement optical signal broadcast between boards so that all boards share common optical channels. By introducing an active coupler to the doubly multiplexed hologram at the center board, signals received from any board can be rebroadcast to all other boards. We describe the design concepts for a centralized optical backplane and the resulting performance and assembly advantages over previously developed guided-wave and free-space optical backplane bus systems used for broadcasting signals. These advantages include equalized fan-out power, increased interconnect distance, and simpler fabrication     

光传输设备中背板业务总线的保护方法

提出了一种光传输设备中背板业务总线的2:5保护方法.在5路TFI-5总线的传输中,只需为其增加两条冗余路径,当接收端接收到的7路信号中有任意2路信号出错时,都可以从剩余的5路信号中解码出原来所要传输的5路TFI-5总线业务信号.设计了编解码逻辑电路,经测试表明该方法可以有效地保护背板业务总线.     

Bi-directional optical backplane bus for general purposemulti-processor board-to-board optoelectronic interconnects

We report for the first time a bidirectional optical backplane bus for a high performance system containing nine multi-chip module (MCM) boards, operating at 632.8 and 1300 nm. The backplane bus reported here employs arrays of multiplexed polymer-based waveguide holograms in conjunction with a waveguiding plate, within which 16 substrate guided waves for 72 (8×9) cascaded fanouts, are generated. Data transfer of 1.2 Gbt/s at 1.3-μm wavelength is demonstrated for a single bus line with 72 cascaded fanouts. Packaging-related issues such as transceiver size and misalignment are embarked upon to provide a reliable system with a wide bandwidth coverage. Theoretical treatment to minimize intensity fluctuations among the nine modules in both directions is further presented and an optimum design rule is provided. The backplane bus demonstrated, is for general-purpose and therefore compatible with such IEEE standardized buses as VMEbus, Futurebus and FASTBUS, and can function as a backplane bus in existing computing environments     

Optical narrow-band filters using optical amplification withdistributed feedback

The amplification characteristics of the distributed-feedback (DFB) laser amplifier are studied. The amplifier has a narrow, single-frequency gain-bandwidth product and the maximum-gain frequency tunability. With these advantages, the amplifier can be applied as an optical narrowband filter. This filter has optical frequency selectivity with an extinction ratio of better than -15 dB for optical inputs separated by 9.8 GHz having different optical input powers. By using a multielectrode DFB laser amplifier, the wide-range tunability of a gain maximum frequency (33.3 GHz) can be obtained while maintaining a constant gain and a constant gain-bandwidth product. Optical frequency selection with an extinction ratio of better then -20 dB can be obtained for two optical inputs separated by 15.4 GHz and having the same input power     

Multichip optical transmitter module for chip-to-chip interconnection on optical PCBs

A multichip module of an optical transmitter, which consists of flip-chip bonded 1/spl times/4 VCSELs on a CMOS driver array IC, is fabricated and demonstrated. The -3 dB bandwidth and adjacent crosstalk of the hybrid integration multichip module are about 4.5 GHz and less than -30 dB, respectively. The whole integrated multichip volume is 1.1/spl times/1.2/spl times/0.52 mm/sup 3/ for four channels.     

双孔径红外变焦光学系统设计

为了解决红外变焦系统短焦部分冷反射严重的问题,提出了一种双孔径设计方法,设计了一种双孔径红外变焦光学系统。系统工作波段为中波3.7 ～4.8 m,焦距为30/150/300 mm,10变倍比,具有100%冷光阑效率。对双孔径系统的短焦部分和单孔径系统短焦部分的冷反射强度进行了对比分析,双孔径系统的冷反射得到有效控制。双孔径红外变焦光学系统具有像质好、变倍比大、短焦冷反射小、结构紧凑的特点,可使大变倍比的红外变焦光学系统在红外成像系统中得到广泛应用。     

利用双激光光源监测甲烷浓度的光吸收法光纤传感器

基于Lamber -Beer定律 ,利用波长为 1.3 3 μm的脉冲lnP/InGaAsP半导体激光器作为测量光源 ,用低损耗的光纤进行光信号的传输并以钽酸锂热释电探测器作光电转换器件 ,设计出了一种新颍的远距离监测甲烷浓度的光纤传感系统。以此光纤传感系统为探头 ,设计出了一种可实时监测甲烷浓度的仪器 ,并能实现 3km的远距离遥测。介绍了该光纤传感系统及由该光纤传感系统构成的监测仪器的基本结构与工作原理 ,讨论了其中的技术难点及其相应的解决方法 ,并给出了监测仪器相应的技术指标     

FPGA GTP技术在光传输设备背板总线的应用

对目前通用的光传输设备背板总线传输的方法进行了分析,针对该方法的不足提出了一种应用FPGA GTP技术完成光传输设备背板总线传输的方式.详细介绍了FPGA GTP技术的优势和特点,并对FPGA GTP进行了合理的软、硬件设计,实现了在光传输设备背板中不同业务、不同速率的混合总线的串行传输.     

Experimental demonstration of 2.5 Gbit/s transmission with 1 mpolymer optical backplane

An optical backplane for high-speed data transmission was experimentally examined. The transmission of 2.5 Gbit/s per channel over a 1 m multimode polymer waveguide is demonstrated     

Optical preamplifier using optical modulation of amplified spontaneous emission in saturated semiconductor optical amplifier

This paper demonstrates a novel optical preamplifier using optical modulation of amplified spontaneous emission (ASE) emitted from a saturated semiconductor optical amplifier (SOA). Requirements on optical alignments and antireflection coating for SOAs can be relaxed and the elimination of an optical filter gives us a large tolerance of an input light wavelength in the proposed optical preamplifier. A small-signal gain of a fabricated preamplifier was over 13.5 dB for an input power of below -20 dBm. An optical gain bandwidth was over 60 nm. We measured the small-signal response of the optically modulated ASE. The 3 dB bandwidths at SOA bias currents of 200, 300, and 400 mA were 5.8, 12.6, and 16.5 GHz, respectively. We also investigated improvements in receiver sensitivities with the proposed optical preamplifier. Our calculation shows a possibility of 10 dB improvement in receiver sensitivities by using the optical preamplifier at 10 Gb/s. The measured receiver sensitivity was -22.7 dBm at 10 Gb/s with the optical preamplifier, which is corresponding to an improvement of 2.5 dB in the receiver sensitivity. Further improvements of the receiver sensitivity can be expected by optimizing the structure of SOAs for saturating ASE.     

Optical broadband access using ATM on a passive optical network

Within the framework of the ‘FITL (fibre in the loop) evolution’, Siemens is developing a prototype based on a passive optical network (PON) for the economic provision of BISDN services in the subscriber access area. It provides 32 subscribers with BISDN access up to a maximum user data rate of 45 Mbit/s per subscriber. The information is transferred via ATM cells and PON-specific overhead in both directions on the PON at a data rate of 155.52 Mbit/s. For transmission to the subscribers, the time division multiplex procedure (TDM) is used. For transmission in the opposite direction, a highly flexible time division multiple access procedure (TDMA) controls the access to PON for the subscriber-side line terminations. In order to keep the transmission system inexpensive emphasis is placed on a digital calibration of the fibre loop delay, a burst transmitter at the subscriber side without amplitude recovery and a burst receiver at the exchange side with purely digital bit synchronization. However, to achieve these features a small part of data rate must be used as a PON specific overhead.     

Optical preamplifier using antireflection-coating-free semiconductor optical amplifier with signal-inverted ASE

We fabricated an antireflection (AR)-coating-free semiconductor optical amplifier (SOA) with an absorbing region for an optical preamplifier. In the fabricated SOA, the resonance of light was fully suppressed so that the amplitude of the ripple of amplified spontaneous emission (ASE) spectra was as small as 0.36 dB, which is comparable to conventional SOAs with AR coating at both facets. We formed an optical preamplifier using the AR-coating-free SOA. The gain saturation of the SOA gives us the signal conversion to ASE and the amplification of the signal. The small-signal fiber-to-fiber and chip gain of the preamplifier were 11.4 and 20.0 dB, respectively. The 3-dB optical gain bandwidth of the preamplifier was about 30 nm.     

采用频域光延迟线的光学相干层析成像

频域光延迟线是一种光学扫描结构,其基本组成是一个衍射光栅、一个透镜和一个扫描镜.把频域光延迟线应用到光学相干层析成像系统中,可以使参考臂扫描速率至少达到数m/s以上,从而实现视频速率的图像获取.从几何光学的角度分析了频域光延迟线的工作原理,分析结果表明在扫描角很小的情况下,入射光的光程或相位变化频率与扫描角频率有较好的线性关系.基于这一结构的光学相干层析成像的结果证明可以避免活体生物组织位移引入的图像模糊.另外,还提出了一种基于微执行器的新扫描装置.     

Isolation enhancement for dual‐band MIMO antenna system using multiple slots loading technique

In this paper, a novel multiple slot loading technique is studied in detail for the isolation enhancement of the dual‐band MIMO antenna system. The proposed MIMO antenna design consists of the microstrip patch loaded with T‐shaped slots parallel to the non‐radiating edge of the patch. The frequency tuning could be achieved by varying the length of the T‐shape slot arm. The proposed MIMO antenna system is optimised for operation in WLAN and WiMAX applications. The isolation enhancement is achieved by providing simple multiple slots loaded in the ground plane between radiating elements. The length of the slots is λ/4 . The system is fabricated and tested using a vector network analyser and anechoic chamber. The reduction in mutual coupling up to ?29.16 dB and ?24.09 dB for the 2.4 GHz and 3.4 GHz, respectively, is achieved. The bandwidths are 62.3 MHz (3.33–3.39 GHz) and 55.5 MHz (2.37–2.42 GHz), respectively. The total gain obtained in this case is 1.8 dBi at 2.4 GHz and 1.2 dBi at 3.4 GHz, respectively. The dimensions of the proposed designed antenna are 70 mm × 60 mm × 1.6 mm. The results were also verified through mutual coupling parameters like envelope correlation coefficient (ECC) and channel capacity loss (CCL) at the desired frequencies.