Maximum Size and Throughput of SOA-Based Optical Burst Switching Nodes With Limited Tuning-Range Wavelength Converters and FDL Buffers

In this paper, we show the physical limitations of semiconductor optical amplifier (SOA)-based switching nodes for optical burst switching (OBS). The investigation covers one basic tune-and-select (TAS) architecture, as well as extensions with wavelength converters of limited tuning range (LTR) and dedicated and shared fiber delay line (FDL) buffers. Their maximum size and throughput are analyzed for nodes with four input/output fibers at different bit rates. As main impairments for signal degradation amplifier noise and crosstalk are considered. It is shown that the advanced contention resolution functionality leads to smaller-sized nodes due to higher losses and noise. Among the considered node architectures the highest maximum throughput can be achieved with TAS-LTR due to the smaller number of SOA noise contributions.      

A fully implemented 12 /spl times/ 12 data vortex optical packet switching interconnection network

A fully functional optical packet switching (OPS) interconnection network based on the data vortex architecture is presented. The photonic switching fabric uniquely capitalizes on the enormous bandwidth advantage of wavelength division multiplexing (WDM) wavelength parallelism while delivering minimal packet transit latency. Utilizing semiconductor optical amplifier (SOA)-based switching nodes and conventional fiber-optic technology, the 12-port system exhibits a capacity of nearly 1 Tb/s. Optical packets containing an eight-wavelength WDM payload with 10 Gb/s per wavelength are routed successfully to all 12 ports while maintaining a bit error rate (BER) of 10/sup -12/ or better. Median port-to-port latencies of 110 ns are achieved with a distributed deflection routing network that resolves packet contention on-the-fly without the use of optical buffers and maintains the entire payload path in the optical domain.     

适于异步光分组交换的反射式光分组头提取方案

基于半导体光放大器(SOA),提出了一种适于异步光分组交换的反射式全光分组头提取方案,它具有比特率透明、开关比(CR)大等特点,适于变长、全光分组交换。仿真了不同速率光分组头的提取效果,分析了系统参数对CR的影响。结果表明,当分组头脉冲速率分别为622Mb/s、2.5Gb/s及10Gb/s时,CR分别为25.46、25及21.7dB。CR随输入脉冲能量、小信号增益及SOA饱和能量的增大而增大,通过适当选取这些参数,可进一步提高系统性能。     

Two-stage Sagnac demultiplexer

Cascading a semiconductor optical amplifier (SOA)-based Sagnac interferometer with a second Sagnac stage allows significant improvement in the overall demultiplexer performance. A theoretical analysis and simulations show that the exploitation of a two-stage architecture results in a demultiplexing window sharpness and time compression. Eye-diagram and Q-factor experimental characterization at 2.5 Gb/s of the demultiplexer is presented, showing a 25% compression in time of the two-stage switching window and a 4.7 Q-factor improvement.     

Simple Rules for Optimizing Asymmetries in SOA-Based Mach–Zehnder Wavelength Converters

In this paper, we present an analysis of semiconductor optical amplifier (SOA)-based differential Mach–Zehnder wavelength converters with a specific focus on optimizing performance through intentional asymmetries in optical power splitting, SOA bias, and interferometer phase bias. By introducing a simple conceptual framework for understanding the amplifier pulse dynamics, two simple yet effective design rules are derived. These design rules are validated using pseudorandom code in a comprehensive computer model, demonstrating the performance penalties that result when attempting optimization using only unequal SOA biasing or phase biasing. This work illustrates that dramatic improvements in extinction and eye margin can be achieved with optimized splitter asymmetries, and have significant implications for improved network performance and converter cascadability.      

半导体光放大器的偏振光开关性能改进

半导体光放大器(SOA)非线性偏振旋转效应的光开关具有开关速度快、易集成等优点,其开关操作可以通过改变注入SOA中的电流而获得。这种偏振光开关的性能主要受注入光功率与控制电流的大小范围来决定。基于SOA中的偏振主态的概念,分析了非线性偏振旋转效应与控制电流的关系,并对不同功率的注入光进行了偏振旋转实验,分别实现了偏振光开关的操作。实验结果表明:随着注入光功率的增加可以提高光开关的分光比,有效改进光开关的性能。当注入光为5 dBm时,光开关的分光比与消光比均可达到30 dB。     

SOA的增益响应特性及其对TOAD解复用器开关窗口的影响

通过数值求解半导体光放大器的增益动力主程,研究了ＳＯＡ的增益响应特性及ｚ光学非对称解复用器开关窗口的影响。     

Performance comparison of spectrum-slicing techniques employing SOA-based noise suppression at the transmitter or receiver

We compare three semiconductor optical amplifier (SOA)-based noise suppression approaches employed in incoherent light spectrum-sliced systems. Although the SOA at the transmitter provides the best absolute noise suppression, it is susceptible to performance degradation in the presence of optical filtering and dispersion. Using the SOA at the receiver can provide good performance while avoiding these limitations, and may provide better value in last-mile access applications.     

Analysis of new all optical polarization-encoded Dual SOA-based ternary NOT & XOR gate with simulation

Photonic Network Communications - Design and performance of all optical ternary NOT & XOR gate using the Dual semiconductor optical amplifier (SOA)-based technology is investigated. The...     

基于半导体光放大器的光单稳态触发器

为实现全光缓存中的光读写控制和光逻辑判断,提出并实验验证了一种基于半导体光放大器(SOA)双环结构的全光单稳态触发器。此触发器的稳态与非稳态激射不同的光波长,状态间静态消光比超过40 dB,切换时间仅仅为1-2个环腔周期,控制信号光波长范围大。通过减小环腔长度可进一步减小两状态之间切换时间,并可作为光缓存的控制单元。     

Efficient Transmission Scheme for AWG-Based DWDM Millimeter-Wave Fiber-Radio Systems

We propose and demonstrate an upstream transmission scheme using a semiconductor optical amplifier (SOA) for arrayed waveguide grating (AWG)-based dense wavelength-division-multiplexed (DWDM) millimeter-wave fiber-radio systems and show improved link performance. In our scheme, unused optical carriers from the cyclic AWG in the downlink (DL) are tapped for uplink (UL) transmission. An SOA in conjunction with the AWG simultaneously amplifies the DL RF subcarriers and UL optical carrier, thus improving carrier-to-sideband ratio in the DL while also yielding an improved power budget for the UL. Our experimental results show that the proposed scheme can be a practical solution for future bidirectional wavelength interleaved DWDM transmission systems     

Performances of Switching Window of Ultrafast Nonlinear Interferometer (UNI) Demultiplexer

In this paper, the theoretical model of the UNI is proposed in detail, which counts on the ultrafast nonlinearities and longitudinal effects of semiconductor optical amplifier (SOA). The transfer function of UNI is also obtained. The switching window, which is a key parameter for demultiplexer, is then analyzed. It's shown that the switching window properties are determined by the length of SOA, the length of the birefringence fiber (BRF), and the parameters of control pulses such as control pulse energy, pulsewidth, power.     

SOA注入电流及载流子寿命对UNI开关窗口的影响

对影响超快非线性干涉仪(UNI)开关窗口的半导体光放大器(SOA)的注入电流及载流子寿命进行了数值模拟实验研究。由于SOA的增益与其注入电流I成正比,与载流子寿命τc成反比。基于此分析了这两种因素对UNI开关窗口的影响,加大注入电流可以提高SOA的增益,使得UNI开关窗口的高度增加;减小载流子寿命使SOA的恢复速度加快,有利于开关窗口的形成。进行了10Gb／s的UNI全光开关实验,实验中用连续光代替数据脉冲以观察窗口形状,通过改变SOA注入电流进行验证。实验表明,在窗口形状不变的条件下,应选用尽量大的SOA注入电流,可使窗口高度增加,与模拟结构基本吻合。     

A novel wavelength conversion scheme based on a single SOA inserted MZI for all-optical switching network

A novel scheme of wavelength conversion based on single semiconductor optical amplifier (SOA) inserted Mach–Zehnder-interferometers (MZI) is proposed to resolve the optical packet contending in the paper. A signal phase adjuster is designed for MZI lower arms to change the optical signal phase difference between MZI upper arms and lower arms accurately. The SOA and input optical signal parameters are discussed and analyzed to optimize the scheme wavelength conversion performance for all-optical switching networks. Numerical analysis and simulation show that more than 20 dB contrast ratio can be achieved for the wavelength conversion at 40 Gbps. In addition, the system is simple structure, stable and photonic integratable.     

Performance of All-Optical Multicasting Via Dual-Stage XGM in SOA for Grid Networking

The letter presents a study on the performance of an all-optical multicasting technique utilizing the nonlinearity of semiconductor optical amplifier (SOA) technology for all-optical grid computing network. The technique not only has the capability to optically control the degree of multicasting but also performs all-optical switching simultaneously. Experimental results show the design's capability to multicast an incoming 10-Gb/s optical signal onto 16 outgoing signals using cross-gain modulation in a single SOA. A second SOA is also included in the design as a 2R regenerator     

Noise suppression of incoherent light using a gain-saturated SOA: implications for spectrum-sliced WDM systems

In this paper, we present an experimental and numerical study of semiconductor optical amplifier (SOA)-based noise suppression and its relevance to high-channel-density spectrum-sliced wavelength-division-multiplexed systems. We show that the improvement in signal quality is accompanied by spectral distortion, which renders it susceptible to deterioration in the presence of subsequent optical filtering. This phenomenon originates from the loss of intensity correlation between spectral components of the SOA output when the signal spectrum is altered. As a consequence, a design tradeoff is introduced between intensity noise and crosstalk in high-channel-density systems. These adverse effects can be overcome by optimized SOA design, resulting in a significant improvement in signal quality.     

SOA-based regenerative amplification of phase-noise-degraded DPSK signals: dynamic analysis and demonstration

A theoretical analysis and an experimental demonstration of semiconductor optical amplifier (SOA)-based regenerative amplification (SORA) of phase noise (PN)-degraded return-to-zero (RZ) differential phase-shift keying (DPSK) signals are presented. The Q-factor improvement is 1.6 dB in single-channel and about 0.8 dB in two non-demultiplexed-channel regimes. The key physical mechanism that enables regeneration by the SORA is the discriminative gain provided by the SOA for the logical 0s versus the logical 1s when two mutually antisymmetric ON-OFF keying (OOK) data trains, created by the DPSK signal, collide in the SOA. The modeling results agree with the experiment.     

Recipe for intensity modulation reduction in SOA-based interferometric switches

This paper presents a theoretical and experimental analysis of saturated semiconductor optical amplifier (SOA)-based interferometric switching arrangements. For the first time, it is shown that such devices can provide enhanced intensity modulation reduction to return-to-zero (RZ) formatted input pulse trains, when the SOA is saturated with a strong continuous-wave (CW) input signal. A novel theoretical platform has been developed in the frequency domain, which reveals that the intensity modulation of the input pulse train can be suppressed by more than 10 dB at the output. This stems from the presence of the strong CW signal that transforms the sinusoidal transfer function of the interferometric switch into an almost flat, strongly nonlinear curve. This behavior has also been verified experimentally for both periodically and randomly degraded, in terms of intensity modulation, signals at 10 Gb/s using the ultrafast nonlinear interferometer as the switching device. Performance analysis both in the time and frequency domains is demonstrated, verifying the concept and its theoretical analysis.     

The Impact of Polarization-Dependent Gain on the Design of Cascaded Semiconductor Optical Amplifier CWDM Systems

We derive an engineering methodology and study the impact of polarization-dependent gain (PDG) on the design of cascaded semiconductor optical amplifier (SOA)-based coarse wavelength-division-multiplexing systems. System specifications can be determined based on receiver optical signal-to-noise ratio (OSNR) requirements and cascaded-SOA OSNR penalty calculations that include a simplified model to calculate PDG statistics.     

Novel Optical Coupling Technique for Enhancing the Performance of Integrated 8-Input/1-Output SOA Gate-Switch Module

We developed 8-input/1-output (8:1) optical gate- switch module that is compact and reliable by proposing and developing a novel lens coupling scheme suitable for an 8:1 integrated SOA device for a multigate semiconductor optical amplifier (MG-SOA) switch system. We first designed special lenses that collect the tilted SOA beams and simultaneously magnify the pitch and beam size, and we fabricated a highly reliable optical module with hermetic sealing and laser-welded joints. The module exhibits low-loss coupling (~ 3.1 dB), high channel crosstalk (~ - 50 dB), high extinction ratio (>81 dB), and high-speed switching (~ 2.5 ns), confirming that this module is applicable to MG-SOA switching systems.