All-optical logic gates containing a two-mode nonlinear waveguide

We propose a new element containing a two-mode nonlinear waveguide consisting of Kerr-like material for all-optical logic circuits. The proposed element, incorporated into the Mach-Zehnder interferometer, functions like a phase shifter. Although the optical waves propagating in the proposed element are monochromatic and identical in polarization, its function is insensitive to the relative phase difference between the incident beams. Using this element, we can realize various logic functions. In this paper, we demonstrate such logic circuits as inverters, distributors, and AND gates     

All-optical tree-based greedy router using optical logic gates and optical flip-flops

Due to ever-increasing throughput demands, the lookup in conventional IP routers based on longest prefix matching is becoming a bottleneck. Additionally, the scalability of current routing protocols is limited by the size of the routing tables. Geometric greedy routing is an alternative to IP routing which replaces longest prefix matching with a simple calculation employing only local information for packet forwarding. For the first time, in this paper we propose a novel and truly all-optical geometric greedy router based on optical logic gates and optical flip-flops. The circuit of the router is constructed through the interconnection of SOAs and directional couplers. The successful functionality of the proposed router is verified through simulation. The circuit enables high data rate throughput.     

All-optical logic devices based on black arsenic–phosphorus with strong nonlinear optical response and high stabilityOA

The Kerr nonlinearity in two-dimensional(2D) nanomaterials is emerging as an appealing and intriguing research area due to their prominent light processing, modulation, and manipulation abilities. In this contribution, 2D black arsenicphosphorus(B-AsP) nanosheets(NSs) were applied in nonlinear photonic devices based on spatial self-phase modulation(SSPM) method. By applying the Kerr nonlinearity in 2D B-AsP, an all-optical phase-modulated system is proposed to realize the functions of “on” and “...     

A model of nonlinear optical transmittance for insulator nanocomposites

A theoretical model of the laser radiation transmittance of insulator nanocomposites containing low concentrations of nanoparticles is proposed. It is shown that the basic mechanisms of low-threshold effects of nonlinear absorption and scattering of laser radiation are, first, the induction of electric dipole moments of nanoparticles in the external field and, second, the orientation of nanoparticles along the polarization direction of this field. The behavior of the transmittance in the vicinity of the central region of a separate absorption band and the dependence of the depth of this band in the transmittance spectrum on the external radiation intensity are considered.     

All-optical network subsystems using integrated SOA-based optical gates and flip-flops for label-swapped networks

In this letter, we demonstrate that all-optical network subsystems, offering intelligence in the optical layer, can be constructed by functional integration of integrated all-optical logic gates and flip-flops. In this context, we show 10-Gb/s all-optical 2-bit label address recognition by interconnecting two optical gates that perform xor operation on incoming optical labels. We also demonstrate 40-Gb/s all-optical wavelength-switching through an optically controlled wavelength converter, consisting of an integrated flip-flop prototype device driven by an integrated optical gate. The system-level advantages of these all-optical subsystems combined with their realization with compact integrated devices, suggest that they are strong candidates for future packet/label switched optical networks.     

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.     

All-optical regeneration based on highly nonlinear photonic crystal fiber

An all-optical regeneration based on selfphase modulation in a highly nonlinear photonic crystal fiber is proposed. The dispersion and nonlinearity properties of a series of photonic crystal fibers are analyzed, and the results show that the nonlinearity coefficient is closely related to the structure of the fiber.In this paper, the nonlinearity coefficient is increased by reducing the effective mode area, and a highly nonlinear photonic crystal fiber with a large air-filling fraction is used as nonlinearity medium in optical regeneration. The numerical results show that good optical regeneration results can be obtained by using a relatively short fiber length due to the high nonlinearity of the fiber. The input peak power launched into the photonic crystal fiber and the parameters of the filter have much influence on optical regeneration. To achieve good optical regeneration, those parameters need to meet certain requirements.Furthermore, the transfer characteristic of the regenerator is also discussed. By adjusting the input peak power and filter parameters, the regenerator can deal with input pulses of different pulse widths.     

All-optical Gbit/s switching using nonlinear optical loop mirror

The switching of a 20 Gbit/s pulse train at 2.5 Gbit/s in an all-fibre NOLM is demonstrated. An entirely semiconductor case powered configuration was used with a long loop (6.4 km) ensuring low power (10 mW) for the switching pulses.<>     

几种基于非线性效应的全光逻辑门及其发展

在未来的超高速光纤系统、全光信息处理及光子计算机系统中,全光数字逻辑器件将成为必不可少的基本单元。本文介绍了几类非线性全光逻辑门的基本结构及工作原理。分析了它们的优缺点,展望了未来的发展趋势。     

Three-dimensional beam propagation analysis of nonlinear opticalfibers and optical logic gates

A three-dimensional (3-D) beam propagation method is described for the analysis of nonlinear optical fibers, where the finite element and finite difference methods are, respectively, utilized for discretizing the fiber cross section and the propagation direction. For efficient evaluation of wide-angle beam propagation Pade approximation is applied to the differential operator along the propagation direction. In order to improve the efficiency and accuracy of solutions, isoparametric elements and numerical integration formulae derived by Hammer et al. are introduced. The propagation characteristics of nonlinear optical fibers with linear core and nonlinear cladding are analyzed, and unique features of nonlinear guided-wave propagation are investigated. Furthermore, all-optical logic gates with practical, 3-D geometry consisting of optical fibers and a nonlinear film are proposed, and their operations of Boolean arithmetic are demonstrated     

Finite-element modeling of one- and two-dimensional MQWsemiconductor optical waveguides

A finite-element characterization of optical waveguides incorporating multiple-quantum-well (MQW) structures is presented. Optical modeling of a planar MQW region is tested to verify that the quantum-well region can be replaced by a homogeneous region with a suitable effective index. Optical modeling of a semiconductor laser incorporating MQW regions with two-transverse-dimensional confinement is then used to identify the range of single-lateral-mode operation. The effective index, the power fraction in the active region, and the spot size dependence on the total optical power for the case of a self-defocusing MQW region are also presented     

基于线性光放大器全光逻辑或非门的仿真研究

为了实现全光逻辑的仿真运算,基于Simulink模块可视化的特点,根据线性光放大器交叉增益调制原理的理论模型,采用模块搭建的方法,实现了全光逻辑"或非"的运算。结果表明,通过Simulink的模块搭建,使其更好地仿真出逻辑"或非"输出结果;适当地选择注入电流组合,逻辑或非的运算效果越佳;由于模块化的结构容易进行修改和扩充,通过模块搭建用于更多的逻辑运算也是可行的。     

All-optical object identification and three-dimensional reconstruction based on optical computing metasurface

Object identification and three-dimensional reconstruction techniques are always attractive research interests in machine vision, virtual reality, augmented reality, and biomedical engineering. Optical computing metasurface, as a two-dimensional artificial design component, has displayed the supernormal character of controlling phase, amplitude, polarization,and frequency distributions of the light beam, capable of performing mathematical operations on the input light field.Here, we propose and ...     

All-optical wavelength conversion of short pulses and NRZ signalsbased on a nonlinear optical loop mirror

Wavelength conversion of short pulses at 10 GHz based on a nonlinear optical loop mirror (NOLM) is experimentally and numerically investigated for the case of small group velocity dispersion and walkoff between the control pulses and continuous lightwaves. Experimental and numerical simulation results show that the pulsewidths of the converted signals at different wavelengths are almost the same, and the pulsewidths are compressed when the peak power of the control pulse is smaller than a certain value. An RZ optical source containing eight wavelengths having a high sidemode suppression ratio, equal amplitudes and almost the same pulsewidths is obtained by using wavelength conversion in a NOLM consisting of a common dispersion shifted fiber. 10 Gb/s NRZ wavelength conversion based on the NOLM is demonstrated for the first time and certain conclusions in some of the references are confirmed by our experimental results     

基于微腔和光学Tamm态耦合的全光二极管

为了实现全光二极管的功能设计,采用1维光子晶体非线性微腔,在1维光子晶体两端设置不同厚度的金属薄膜,并运用非线性传输矩阵方法研究了该结构的传输属性。结果表明,两个非对称光学Tamm态和非线性微腔的耦合结构呈现双稳态,且滞回线的位置与入射方向有关,具有全光二极管功能;光二极管的性能依赖于微腔厚度和两个金属薄膜的厚度比。该设计为全光二极管的性能优化提供了参考。     

Optical-signal-processing device based on waveguide-type variable delay lines and optical gates

In this paper, an optical-signal-processing device mainly designed for time-slot switching is demonstrated. The device is composed of variable delay-line arrays fabricated by planar lightwave circuit technology and high-speed optical gates. The variable delay-line arrays consist of transversal-form or lattice-form optical circuits. The operating principle is based on serial-to-parallel conversion, adjustment of the delay time between the parallel signals, and the gating of the optical bits or packets in the optical region. The device does not require any interaction between lightwaves through optical nonlinear effects or filter banks for code matching. As an example of its operation, label-processing functions are demonstrated, specifically the label swapping of optical return-to-zero pulses. The merits of the proposed device are described and problems that must be solved are also discussed.     

All-optical regeneration in one- and two-pump parametric amplifiers using highly nonlinear optical fiber

We describe the operation of a two-pump parametric optical regenerator. It is shown that higher order parametric coupling provides optical regeneration with a high extinction ratio. Excessive spectral broadening is studied in a two-pump architecture and compared with that of the one-pump parametric regenerator. We show that the spectral widths of the higher order terms can be controlled in amplifiers by using counterphased optical pumps.     

High-speed, all-optical XOR gates using semiconductor optical amplifiers in ultrafast nonlinear interferometers

We will review three recently-proposed high-speed, all-optical Exclusive OR (XOR) gates operating at 40 and 85?Gb/s, which were demonstrated using ultrafast nonlinear interferometers (UNIs) incorporating semiconductor optical amplifiers (SOAs). The first 40-Gb/s XOR gate was obtained using a dual UNI configuration. The second is a 40-Gb/s XOR gate without additional probe beam required, where the only inputs launched into the setup were data A and B. The XOR logic of data A and B is the sum of two components (A)B and(A)B , each of which was obtained from the output of UNI via cross-phase modulation (XPM) in SOAs. Furthermore, an 85-Gb/s XOR gate is, by far, the fastest XOR gate realized by SOAs, which was also demonstrated using a dual UNI structure. The operating speed of the XOR gate was enhanced by incorporating the recently proposed turbo-switch configuration. In addition, the SOA switching pulse energies of these XOR gates were lower than 100 fJ.     

基于半导体光放大器环形腔的全光频率倍增/恢复

提出了一种利用具有干涉作用的半导体光放大器(SOA)环形腔实现全光频率倍增/恢复的新方法,该方法同相关实验比较具有显著优势.数值结果表明:2.5 GHz的光脉冲序列注入SOA环形腔,可输出重复频率为5～25 GHz振幅均衡、与入射光偏振无关的光脉冲序列;SOA的偏置电流对SOA环形腔输出脉冲振幅的均衡度影响显著,对于基频为2.5 GHz和10 GHz输入脉冲序列分别存在一最佳的SOA偏置电流值;从传输速率为2.5 Gbit/s的27-1伪随机信号中可提取出重复频率为分别2.5 GHz和5 GHz的幅度均衡的时钟信号.