Controllable all-optical stochastic logic gates and their delay storages based on the cascaded VCSELs with optical-injection

Using the dynamical properties of the polarization bistability that depends on the detuning of the injected light,we propose a novel approach to implement reliable all-optical stochastic logic gates in the cascaded vertical cavity surface emitting lasers（VCSELs） with optical-injection.Here,two logic inputs are encoded in the detuning of the injected light from a tunable CW laser.The logic outputs are decoded from the two orthogonal polarization lights emitted from the optically injected VCSELs.For the same logic inputs,under electro-optic modulation,we perform various digital signal processing（NOT,AND,NAND,XOR,XNOR,OR,NOR） in the all-optical domain by controlling the logic operation of the applied electric field.Also we explore their delay storages by using the mechanism of the generalized chaotic synchronization.To quantify the reliabilities of these logic gates,we further demonstrate their success probabilities.

High-performance chiral all-optical OR logic gate based on topological edge states of valley photonic crystal

For all-optical communication and information processing,it is necessary to develop all-optical logic gates based on photonic structures that can directly perform logic operations.All-optical logic gates have been demonstrated based on conventional waveguides and interferometry,as well as photonic crystal structures.Nonetheless,any defects in those structures will introduce high scattering loss,which compromises the fidelity and contrast ratio of the information process.Based on the spin-valley locking effect that can achieve defect-immune unidirectional transmission of topological edge states in valley photonic crystals(VPCs),we propose a high-performance all-optical logic OR gate based on a VPC structure.By tuning the working bandwidth of the two input channels,we prevent interference between the two channels to achieve a stable and high-fidelity output.The transmittance of both channels is higher than 0.8,and a high contrast ratio of 28.8 dB is achieved.Moreover,the chirality of the logic gate originated from the spin-valley locking effect allows using different circularly polarized light as inputs,representing“1”or“0”,which is highly desired in quantum computing.The device’s footprint is 18μm×12μm,allowing high-density on-chip integration.In addition,this design can be experimentally fabricated using current nanofabrication techniques and will have potential applications in optical communication,information processing,and quantum computing.

Realizing reliable XOR logic operation via logical chaotic resonance in a triple-well potential system

There exists an optimal range of intensity of a chaotic force in which the behavior of a chaos-driven bistable system with two weak inputs can be consistently mapped to a specific logic output. This phenomenon is called logical chaotic resonance(LCR). However, realization of a reliable exclusive disjunction(XOR) through LCR has not been reported.Here, we explore the possibility of using chaos to enhance the reliability of XOR logic operation in a triple-well potential system via LCR. The success probability P of obtaining XOR logic operation can take the maximum value of 1 in an optimal window of intensity D of a chaotic force. Namely, success probability P displays characteristic bell-shaped behavior by altering the intensity of the chaotic driving force, indicating the occurrence of LCR. Further, the effects of periodic force on LCR have been investigated. For a subthreshold chaotic force, a periodic force with appropriate amplitude and frequency can help enhance the reliability of XOR logic operation. Thus, LCR can be effectively regulated by changing the amplitude and frequency of the periodic force.

All-optical XNOR and AND gates simultaneously realized in a single semiconductor optical amplifier with improved dynamics

All-optical XNOR and AND logic gates using four-wave mixing （FWM） and cross-gain modulation （XGM） in a single semiconductor optical amplifier （SOA） with improved dynamics are simultaneously realized. By numerical simulation, the effects of the input optical wave powers and injection current on the critical factors of the logic gate performances, such as the ON-OFF contrast ratio, the power-output level of the logic ＇1＇, and the difference between power outputs of the logic ＇1＇, are investigated in detail. In addition, the effect of the counter-propagating CW pump on the gain recovery is analysed.

低功耗三输入AND/XOR门的设计

三输入AND/XOR门是Reed-Muller(RM)逻辑电路的一种基本复合门电路单元.针对现有AND/XOR门电路由AND门和XOR/XNOR门级联而成,导致电路延时长、功耗大等问题,提出一种晶体管级的CMOS逻辑和传输逻辑混合的低功耗三输入AND/XOR门电路.首先在55nm CMOS工艺下,对所设计电路进行原理图和版图设计;然后对版图进行寄生参数提取,并在不同工艺角下与基于典型级联结构的电路进行后仿真分析和比较.实验结果表明,在典型工艺角下,所提出的电路的面积、功耗和功耗延迟积的改进最高分别达到18.79%,26.67%与31.25%.

基于量子遗传算法的XOR/AND电路功耗和面积优化

通过研究量子遗传算法、XOR/AND逻辑展开式及其对应电路的功耗和面积关系,提出一种基于量子遗传算法的单输出XOR/AND电路功耗和面积同时优化的算法.从量子比特、量子叠加态的概念出发,结合XOR/AND电路的功耗估计模型,以XOR/AND门电路数衡量电路面积,利用染色体编码、适应度函数构造和量子旋转门调整等方法,有效实现了功耗和面积的折中.将提出算法与遍历算法和整体退火遗传算法进行比较,结果表明该算法高效、稳定、收敛速度快.对较大规模电路的测试结果表明,该算法的优化结果与极性为零时的XOR/AND电路相比,功耗和面积平均节省了81.7%和54.7%.

三输入高性能AND/XOR复合门电路设计

针对现有"与/异或"(AND/XOR)复合门级联设计电路存在功耗大、延时长等不足,提出一种基于晶体管级的三输入AND/XOR复合门电路结构.通过采用多轨结构、缩短传输路径以及混合CMOS逻辑设计方法,克服了原有电路中单一逻辑和单轨结构信号路径长的不足,进而提高了电路性能.在55nm的CMOS技术工艺和PTM多种工艺下,经过HSPICE模拟和Cadence提取版图的后仿真,显示所设计的电路具有正确的逻辑功能,相较于采用门电路级联而成的AND/XOR电路,本电路在不同负载、频率和PVT组合等情况下的延时、功耗和功耗延迟积(PDP)都得到了明显改善.

低功耗XOR门的快速分解技术

为了在相对短的时间内得到基于XOR门电路的最优结构,并达到功耗优化的目的,以XOR门输入信号的概率为依据进行低功耗分解,提出了一种新的基于XOR门的电路功耗优化技术.实验结果表明:提出的算法能在更短的时间内实现功耗优化,且比现有的方法最多可提高8.9%,同时也证明了提出的算法在功耗节省方面比其他同类算法更有效.

Performance Evaluation of Efficient XOR Structures in Quantum-Dot Cellular Automata (QCA)

Quantum-dot cellular automaton (QCA) is an emerging, promising, future generation nanoelectronic computational architecture that encodes binary information as electronic charge configuration of a cell. It is a digital logic architecture that uses single electrons in arrays of quantum dots to perform binary operations. Fundamental unit in building of QCA circuits is a QCA cell. A QCA cell is an elementary building block which can be used to build basic gates and logic devices in QCA architectures. This paper evaluates the performance of various implementations of QCA based XOR gates and proposes various novel layouts with better performance parameters. We presented the various QCA circuit design methodology for XOR gate. These layouts show less number of crossovers and lesser cell count as compared to the conventional layouts already present in the literature. These design topologies have special functions in communication based circuit applications. They are particularly useful in phase detectors in digital circuits, arithmetic operations and error detection & correction circuits. The comparison of various circuit designs is also given. The proposed designs can be effectively used to realize more complex circuits. The simulations in the present work have been carried out using QCADesigner tool.

基于XMG的乘法器电路等价性验证算法

组合电路等价性验证是数字集成电路设计自动化(EDA)中的重要部分,随着算术电路在现代计算机系统中的占比逐渐增大,传统的等价性验证算法在验证多比特算术电路,尤其是乘法器电路时面临挑战.对此,提出一种基于XOR-Majority Graph(XMG)逻辑表示的组合电路等价性验证算法.首先将2个待验证电路构建成的联接(Miter)电路进行XMG逻辑重写;然后在等价性一致的前提下对XMG的节点个数和逻辑深度进行逻辑重写优化;最后调用布尔可满足性(SAT)求解器和仿真器进行验证,得到最终等价性验证结果.实验结果表明,与ABC,Lingeling等工具相比,所提算法在验证时间上实现了平均489倍、最高1472倍的加速.

All-optical logic gates and a half-adder based on lithium niobate photonic crystal micro-cavities

All-optical logic gates including AND, XOR, and NOT gates, as well as a half-adder, are realized based on twodimensional lithium niobate photonic crystal(PhC) circuits with Ph C micro-cavities.The proposed all-optical devices have an extinction ratio as high as 23 dB due to the effective all-optical switch function induced by twomissing-hole micro-cavities.These proposed devices can have potential implementation of complex integrated optical functionalities including all-optical computing in a lithium niobate slab or thin film.

XOR spin logic operated by unipolar current based on field-free spin-orbit torque switching induced by a lateral interface

Spin logics have emerged as a promising avenue for the development of logic-in-memory architectures.In particular,the realization of XOR spin logic gates using a single spin-orbit torque device shows great potential for low-power stateful logic circuits in the next generation.In this study,we successfully obtained the XOR logic gate by utilizing a spin-orbit torque device with a lateral interface,which was created by local ion implantation in the Ta/Pt/Co/Ta Hall device exhibiting perpendicular magnetic anisotropy.The angle of the lateral interface is set at 45°relative to the current direction,leading to the competition between symmetry breaking and current-driven Néel-type domain wall motion.Consequently,the field-free magnetic switching reversed is realized by the same sign of current amplitude at this interface.Based on this field-free magnetic switching behavior,we successfully proposed an XOR logic gate that could be implemented using only a single spin-orbit torque Hall device.This study provides a potentially viable approach toward efficient spin logics and in-memory computing architectures.

Design of a node architecture for logic-calculation Nased all-optical network coding scheme

Network coding brings many benefits for multicast networks. It is necessary to introduce network coding into optical networks. Nevertheless, the traditional network coding scheme is hard to be implemented in optical networks because of the weak operation capability in photonic domain. In the paper, we focused on realizing two-channel network coding in all-optical multicast networks. An optical network coding scheme which can be realized via logic shift and logic XOR operations in photonic domain was proposed. Moreover, to perform the network coding scheme the coding node structure was designed and the operation principle and processes were illustrated in detail. In the end of the paper, the performance and the cost of different all-optical multicast mode were compared and analyzed.

Improved all-optical OR logic gate based on combined Brillouin gain and loss in an optical fiber

Improved all-optical OR gates are proposed, using a novel fiber nonlinearity-based technique, based on the principles of combined Brillouin gain and loss in a polarization-maintaining fiber （PMF）. Switching contrasts are simulated to be between 82.4%-83.6%, for two respective configurations, and switching time is comparable to the phonon relaxation time in stimulated Brillouin scattering （SBS）.

Liquid phase exfoliated boron nanosheets for all-optical modulation and logic gates

Boron nanosheets possess unique photoelectric properties, including photosensitivity, photoresponse,and optical nonlinearity. In this article, we show the interaction between light and boron nanosheets in which concentric rings formed in the far field, which attributed to the strong Kerr nonlinearity of boron nanosheets. Furthermore, the distortion, regulation and relationship between the Kerr nonlinearity and effective mass or carrier mobility of the diffraction rings of boron nanosheets have been investigated.Our work shows that the spatial self-phase modulation effect of boron nanosheets is indeed caused by nonlocal electronic coherence. In addition, we have implemented all-light modulation and all-light logic gates based on the prepared boron nanosheets. We believe that our results will provide a powerful demonstration of nonlinear photonic devices based on boron nanosheets and a reference for photonic devices based on two-dimensional materials.

All-optical logic gates based on hierarchical photonic crystal modulated photoluminescence of perovskite nanocrystals

Halide perovskites exhibit high performance in all sorts of optoelectronic and photonic areas, suggesting their huge potential in integrated photonic devices. However, until now, all optical logic gates based on perovskites are still rarely explored, hindering the development of all-optical networks and computing. Herein, a new concept of all-optical logic gates is proposed based on the modulation of photoluminescence(PL) from perovskite nanocrystals(PNCs). A hierarchical photonic crystal(Hie PhC) is developed by self-assembling polystyrene(PS) and SiO2nanoparticles, which exhibit a higher PL enhancement than that of a monolayer PhC. Moreover, the light-controlled PL is realized by taking advantage of the high thermal response of the PL from PNCs/Hie PhC on polyethylene(PE) substrate, assisted by a graphene layer for light-heat conversion. Consequently, optical diode and triode are achieved based on the modulated PL, which exhibit contrast ratios(CR) of 24.7 and 74.0 dB, respectively.All-optical logic gates, including “AND”, “OR” and “NOT”, are realized based on the optical diode and triode.

Parallel all-optical logic operations based on metasurface polarization optics

We developed a general framework for parallel all-optical logic operations with independent phase control of arbitrary orthogonal polarization state enabled by a single-layer metasurface.A pair of orthogonal circular polarized bases are used as two input channels of the logic operator,and their four combinations perfectly match various binary input states.Correspondingly,distinct phase profiles are encoded into the metasurface,which enables parallel operation of the two logic gates by way of polarization switching.It allows for an efficient and compact way to implement multi-channel multiplexed logic gate operations with the capability of fast optical computing at the chip scale.

High performance integrated photonic circuit based on inverse design method

The basic indexes of all-optical integrated photonic circuits include high-density integration,ultrafast response and ultralow energy consumption.Traditional methods mainly adopt conventional micro/nano-structures.The overall size of the circuit is large,usually reaches hundreds of microns.Besides,it is difficult to balance the ultrafast response and ultra-low energy consumption problem,and the crosstalk between two traditional devices is difficult to overcome.Here,we propose and experimentally demonstrate an approach based on inverse design method to realize a high-density,ultrafast and ultra-low energy consumption integrated photonic circuit with two all-optical switches controlling the input states of an all-optical XOR logic gate.The feature size of the whole circuit is only 2.5μm×7μm,and that of a single device is 2μm×2μm.The distance between two adjacent devices is as small as 1.5μm,within wavelength magnitude scale.Theoretical response time of the circuit is 150 fs,and the threshold energy is within 10 fJ/bit.We have also considered the crosstalk problem.The circuit also realizes a function of identifying two-digit logic signal results.Our work provides a new idea for the design of ultrafast,ultra-low energy consumption all-optical devices and the implementation of high-density photonic integrated circuits.

全光异或逻辑门技术

文中对现有的全光异或逻辑门方案作了一个概括,比较了基于半导体光放大器(SOA)的各种设计,特别是带有干涉结构的技术方案。

QD-SOA的四波混频及DPSK信号的异或逻辑研究

采用有限差分方法对量子点半导体光放大器(QD-SOA)中的四波混频(FWM)现象进行了研究。通过仿真计算,分析了多个参数对四波混频效率的影响。增强泵浦光功率、增大QD-SOA的长度以及注入电流,四波混频效率明显增大。增大探测光功率以及泵浦光和探测光的波长间隔,四波混频效率均降低。基于四波混频效应实现了差分相移键控信号的异或逻辑操作,模拟得到了异或逻辑的时域和频域输出结果。在多个波长位置同时实现了异或逻辑,并对32比特的序列异或操作进行了仿真研究,得到了异或逻辑的时序结果及眼图。