数字电视时代1550光纤传输技术及应用

详细探讨了数字电视时代数字电视联网的需求及比较,结果表明:1 550光纤传输技术结合光色散补偿技术,在数字电视联网应用中有很强的技术和成本等综合竞争优势。对1 550光纤传输技术在数字电视联网应用中出现的问题以及是否需要色散补偿的问题进行了分析,得出1 550光纤传输技术在数字电视联网应用中色散补偿是很有必要的。最后介绍了1 550数模混合传输网络应用设计实例。     

数字电视时代1 550光纤传输技术及应用

详细探讨了数字电视时代数字电视联网的需求及比较,结果表明:1 550光纤传输技术结合光色散补偿技术,在数字电视联网应用中有很强的技术和成本等综合竞争优势.对1 550光纤传输技术在数字电视联网应用中出现的问题以及是否需要色散补偿的问题进行了分析,得出1 550光纤传输技术在数字电视联网应用中色散补偿是很有必要的.最后介绍了1 550数模混合传输网络应用设计实例.     

Standards update: routing for optical networks

We focus on a component of the optical control plane: routing. We give a quick overview of what routing functionality can mean in the optical control plane and compare that with routing in IP networks. We also look at this functionality from the point of view of a carrier running an optical network. We point out some areas of potential disagreement and give an update of the status of optical routing at the various standards bodies.     

Dependence of transmission curves on input optical power in an electroabsorption modulator

We present a novel method to extract the optical absorption coefficient of a semiconductor electroabsorption modulator (EAM) with antireflection coated facets. Only the transmission and photocurrent data are needed with this method. The method allows to obtain the total optical coupling loss, internal quantum efficiency, and optical absorption coefficients when input optical power is low. We also developed a method to analyze optical absorption coefficient with the saturation effect. By using those methods, we investigated the dependence of the transfer curves on the input optical power in a multiple-quantum-well EAM. The optical loss saturation effect and the increase of device temperature are the dominant mechanisms for the dependence of transfer curves on the input optical power in the low bias region and the high bias region, respectively.     

All-optical signal processing based on semiconductor optical amplifiers

In this paper,we review the recent progress in the optical signal processing based on the nonlinearity of semiconductor optical amplifiers (SOAs).The four important optical signal processing functional blocks in optical switching are presented,i.e.,optical wavelength conversion,optical regeneration,optical logic,and optical format conversion.We present a brief overview of optical wavelength conversion,and focus on various schemes to suppress the slow gain recovery of the SOA and improve the operating speed of the SOA-based optical switches.Optical regeneration including re-amplification,re-shaping and re-timing is also presented.Optical clock recovery that is essential for optical regeneration is reviewed.We also report the recent advances in optical logic and optical format conversion,respectively.After reviewing the four important optical signal processing functional blocks,the review concludes with the future research directions and photonic integration.     

Optical Signal Processor Using Electro-Optic Polymer Waveguides

We have investigated an optical signal processor using electro-optic polymer waveguides operating at a wavelength of 1.55 $mu$m. Due to recent developments, many useful optical devices have become available such as optical filters, modulators, switches, and multiplexers. It will be useful to have a single optical device, which is reconfigurable to implement all of these functions. We call such a device an “optical signal processor,” which will play a similar role to digital signal processors in electrical circuits. We realize such an optical device in a planar lightwave circuit. Since the planar lightwave circuits are based on the multiple interference of coherent light and can be integrated with significant complexity, they have been implemented for various purposes of optical processing such as optical filters. However, their guiding waveguides are mostly passive, and the only viable mechanism to reconfigure their functions is thermal effects, which is slow and cannot be used for high-speed applications such as optical modulators or optical packet switches. On the other hand, electro-optic polymer has a very high electro-optic coefficient and a good velocity match between electrical and optical signals, thus, permitting the creation of high-speed optical devices with high efficiency. Therefore, we have implemented a planar lightwave circuit using the electro-optic polymer waveguides. As a result, the structure is complex enough to generate arbitrary functions and fast enough to obtain high data rates. Using the optical signal processor, we investigate interesting applications including arbitrary waveform generators.      

OXC节点级联的信噪比计算

文章给出了计算OXC级联信噪比的一般解析模型,并针对“信号功率均衡”和“总功率均衡”两种方案进行了研究,分析了在这两种特定情况下系统的信噪比特性。同时还给出了OXC中输入EDFA和输出EDFA特性对系统信噪比的不同影响,得出了在设计OXC时对输入EDFA和输出EDFA优化设计的原则。     

Signaling and Control Procedures Using Generalized MPLS Protocol for IP over an Optical Network

This paper reviews the existing research activities on signaling and control procedures for IP over optical networks. We focus on the IP‐centric signaling and control architecture based on the generalized multi‐protocol label switching (GMPLS) protocol and analyze various scenarios and technical issues for deploying the IP over an optical network. We analyze the signaling and operations and administration and maintenance requirements for integrating an IP network and an optical network in order to cope with the high bandwidth and poor resource granularity of the optical network, including the optical cross‐connect system. On the basis of network architecture and a reference configuration model, we investigate the GMPLS‐based control architecture and interconnection model appropriate for controlling IP bandwidth and optical lambda resources. The signaling and control procedure based on GMPLS on optical user‐network interface and network‐network interface are comparatively investigated to provide the optical lightpath. We also study protection and restoration procedures to protect link failure when it applies to GMPLS signaling.     

Unusual fault detection and loss analysis in optical fiber connections with refractive index matching material

We investigated and analyzed an unusual fault that occurs in optical access fiber networks, which is caused by a defective fiber connection. We developed a fault-detection system to locate such a fault by using both optical power level and optical pulse measurement methods. We investigated a defective mechanical splice in three laboratory tests: outward appearance, non-destructive, and dismantled. As a result, we confirmed that the defective mechanical splice had large gaps of more than 10 μm. We also analyzed the unusual fault that occurs from such a defective mechanical splice in mechanically transferrable (MT) connector experiments. The experimental results revealed that the optical performance of fiber connections with a mixture of refractive index matching material and air-filled gaps was extremely unstable and varied widely. In the worst case, the insertion loss worsened to more than 30 dB. The case of the fault caused by a mixture of refractive index matching material and air-filled gaps between the ends of optical fibers is thought to occur independently of the sorts or structures of optical fiber connectors and could be a characteristic peculiar to optical fiber connections using refractive index matching material. These findings can be applied to optical fiber connections that use refractive index matching material, such as MT connectors in outside underground facilities, mechanical splices, or field assembly connectors at aerial and home sites in optical access networks. These findings also support the practical construction and operation of optical network systems.     

New approach to lossy optical waveguides

We review a method we recently developed to construct Green's function in the paraxial approximation associated with arbitrary graded-index optical elements. We then demonstrate that our formalism may be successfully applied to calculate in an extremely simple fashion the optical losses associated with bent and perturbed optical waveguides.     

囚禁冷原子或冷分子的可控制光学八阱及其光学晶格

提出了一种利用单束平面光波照明二元π相位板与透镜组合系统实现冷原子或冷分子囚禁的可控制光学八阱的方案,计算了光学势阱的光强分布和可控光学八阱的几何与光学特征参数、强度梯度及其曲率;讨论了从光学八阱到四阱或到双阱的演化过程。研究表明,通过相对于透镜移动二元π相位板可实现光学八阱到四阱或到双阱的连续双向演化。讨论了利用该可控光学八阱组成二维光学晶格的方案。     

Design of photonic rearrangeable networks with zero first-orderswitching-element-crosstalk

The development of optical cross-connect architectures is a very important topic today. We consider here in particular the class of optical space-division switching fabrics configured as multistage structures built with 2×2 optical switching elements (SEs) and derived from a combination of vertical replication and horizontal expansion of Banyan networks. We determine the necessary and sufficient conditions for these matrices to be rearrangeably nonblocking and free of first-order crosstalk in SEs. This impairment is one of the major limitations in optical cross-connect performance. We focus on rearrangeable matrices since they have lower complexity than their strict-sense nonblocking counterparts. Given the current high cost of optical SEs, the rearrangeable solution looks attractive today     

Optical packet switching and buffering by using all-optical signal processing methods

We present a 1 /spl times/ 2 all-optical packet switch. All the processing of the header information is carried out in the optical domain. The optical headers are recognized by employing the two-pulse correlation principle in a semiconductor laser amplifier in loop optical mirror (SLALOM) configuration. The processed header information is stored in an optical flip-flop memory that is based on a symmetric configuration of two coupled lasers. The optical flip-flop memory drives a wavelength routing switch that is based on cross-gain modulation in a semiconductor optical amplifier. We also present an alternative optical packet routing concept that can be used for all-optical buffering of data packets. In this case, an optical threshold function that is based on a asymmetric configuration of two coupled lasers is used to drive a wavelength routing switch. Experimental results are presented for both the 1 /spl times/ 2 optical packet switch and the optical buffer switch.     

A 1.3/1.55-μm wavelength-division multiplexing optical moduleusing a planar lightwave circuit for full duplex operation

We developed a hybrid integrated optical module for 1.3/1.55-μm wavelength-division multiplexing (WDM) full-duplex operation. The optical circuit was designed to suppress the optical and electrical crosstalk using a wavelength division multiplexing filter, and an optical crosstalk of -43 dB and an electrical crosstalk of -105 dB were achieved with a separation between the transmitter laser diode and the receiver photodiode of more than 9 mm. We used the optical circuit design to fabricate an optical module with a bare chip preamplifier in a package. This module exhibited a full duplex operation of 156 Mbit/s with a minimum sensitivity of -35.2 dBm at a bit error rate of 10^-10     

有机材料在光限制中的应用

对光限制器件的特性进行了简单的评述,并对由自散焦过程产生光限制的机理进行了分析.采用z-扫描方法对有机材料分散红一的非线性折射过程和光限制特性进行了实验研究.对其结果进行了分析讨论,这种分析对于以自作用效应产生最佳光限制效应是十分有用的.     

有机材料在光限制中的应用

对光限制器件的特性进行了简单的评述,并对由自散焦过程产生光限制的机理进行了分析.采用z-扫描方法对有机材料分散红一的非线性折射过程和光限制特性进行了实验研究.对其结果进行了分析讨论,这种分析对于以自作用效应产生最佳光限制效应是十分有用的.     

光控光开关的发展和应用

综述了光控光开关的发展状况以及它在未来全光网络中的应用 ;分析了几种典型的光控光开关实现方案的结构及原理 ;详细论述了光控光开关在全光网络中的各种应用 ,并通过分析和论述指出光控光开关将在未来的大容量全光网络中发挥关键作用。     

On-Chip Optical Interconnect

We describe a cost-effective and low-power-consumption approach for on-chip optical interconnection. This approach includes an investigation into architectures, devices, and materials. We have proposed and fabricated a bonded structure of an Si-based optical layer on a large-scale integration (LSI) chip. The fabricated optical layer contains Si nanophotodiodes for optical detectors, which are coupled with SiON waveguides using surface-plasmon antennas. Optical signals were introduced to the optical layer and distributed to the Si nanophotodiodes. The output signals from the photodiodes were sent electrically to the transimpedance-amplifier circuitries in the LSI. The signals from the photodiodes triggered of the circuitries at 5 GHz. Since electrooptical modulators consume the most power in on-chip optical interconnect systems and require a large footprint, they are critical to establish on-chip optical interconnection. Two approaches are investigated: 1) an architecture using a fewer number of modulators and 2) high electrooptical coefficient materials.     

Practical physical-layer encryption: the marriage of optical noise with traditional cryptography

We describe an emerging method of encryption suitable for high-speed optical communication networks. This encryption protocol combines traditional electronic cryptographic algorithms with the physical effect of optical noise of quantum origin to create a highly secure method of secret communications. The resulting optical signal is compatible with today's high speed fiber optic infrastructure including optical amplification and add/drop multiplexing. Systems implementing this protocol can be constructed with common commercially available components. We describe experimental results obtained with a 2.5 Gb/s system. The encrypted signal is shown to travel error-free through >500 km of optical fiber. Simulations show that reaches and data rates consistent with modern long haul optical networks are attainable.     

Frequency detuning effects in a loop-back WDM-PON employing gain-saturated RSOAs

We report that, in a loop-back wavelength-division-multiplexed passive optical network link with gain-saturated reflective semiconductor optical amplifiers, the upstream performance is strongly affected not only by the gain saturation but also by the selective spectral filtering caused by the frequency difference between the optical downstream signal and the cascaded filter's passband. We experimentally investigate these effects and propose to use an additional negatively detuned optical filter at an optical network terminal to improve the upstream transmission performance.