All-optical multiple-channel logic XOR gate for NRZ-DPSK signals based on nondegenerate four-wave mixing in a silicon waveguide

We report an all-optical multiple-channel exclusive OR (XOR) gate for 10?Gbits/s non-return-to-zero differential phase-shift keying (NRZ-DPSK) signals using nondegenerate four-wave mixing in a silicon waveguide. The function of the logic XOR gate is experimentally demonstrated using 40?bit DPSK sequences. Also, the eye diagram of the XOR signal is clearly observed as the incident signals are both modulated by DPSK sequences originating from 2(31)-1 pseudorandom binary sequences.     

Reconfigurable all-optical logic gate using four-wave mixing (FWM) in HNLF for NRZ-PolSK signal

We demonstrate a reconfigurable all-optical logic gate for NRZ-PolSK signal based on FWM in a highly nonlinear fiber at 10 Gb/s. Half subtracter, XOR, AB?, āB or XNOR, AND, and NOR logic gates can be implemented simultaneously. The input power for the HNLF is optimized to be as low as about 15.2 dBm and the high Q factors above 8 dB for eye diagrams are achieved. Experimental results show Q factors of AB?, āB, AND, and NOR were higher than those of XOR, and XNOR. Error-free operation is achieved experimentally for 10 Gb/s 2⁷-1 pseudorandom bit sequence (PRBS) data. Power penalties for the logic gate are less than 3 dB. Simulation analysis about the wavelength characteristic for all logic gates is given and it predicts that the reconfigurable logic gate can realize error-free operation when the wavelength separation is less than 5 nm.     

Ultrafast all-optical XOR logic gate based on a symmetrical Mach-Zehnder interferometer employing SOI waveguides

We present an integrated Silicon-on-Insulator (SOI) based Mach-Zehnder interferometer (MZI) in order to perform ultrafast all-optical XOR logic gate operation with a bit rate of ∼ 0.33 Tb/s. A numerical simulation is carried out in order to study various parameters such as extinction ratio and eye-opening parameters, characterizing the performance of the XOR logic gate. The output XOR logic gate signal can have improved extinction and eye margin if the initial powers of primary signals and the probe continuous-wave (CW), and SOI waveguide length are judiciously adjusted.     

基于高非线性光纤中四波混频饱和效应的NRZ-DPSK和RZ-DPSK信号幅度再生实验

利用高非线性光纤中的四波混频饱和效应,实验展示了42.8 Gbit/s非归零差分相移键控（NRZ-DPSK）信号和归零差分相移键控（RZ-DPSK）信号的全光幅度再生.测量了NRZ-DPSK信号和RZ-DPSK信号经过高非线性光纤的功率传递曲线.在平均输入功率均为16 dBm的条件下,对两种调制格式的再生性能进行了比较.实验结果显示RZ-DPSK信号具有更好的幅度再生性能.     

Ultra high-speed optical signal processing based on single SOA at 60 Gb/s

The paper shows the design of all-optical logic gates OR, AND, NOT, NOR, XNOR, XOR at ultra high speed by using SOA. The simulations of all logic gates are obtained by XGM and FWM in SOA at 40 Gb/s and 60 Gb/s. The OR, AND, NOR logic between two data sources are obtained using a pump signal, while another logic XNOR using two data. The NOT, XOR obtained using FWM and XGM combined. Thus realization of these logics at 40 Gb/s and 60 Gb/s will lead revolution growth in optical signal processing for high-speed operation.     

Passive, “self-trapped family” all-optical half adder using all-optical XOR and AND gates

The paper presents an alternative novel approach to obtain all-optical logic. We show that XOR, NOT, and AND logic could be obtained by appropriately setting parameter of all-optical passive transistor. An AND gate followed by NOT gives NAND logic (building block) that, in principle can provide complete set of passive, fiber compatible “self-trapped family” all-optical logic gates (with Boolean completeness) and may find many possibilities in the area of all-optical computing. To give one example, we propose all-optical half adder.     

Photonic chip-based all-optical XOR gate for 40 and 160 Gbit/s DPSK signals

We demonstrate a photonic chip-based all-optical exclusive-OR (XOR) gate for phase-encoded optical signals via four-wave mixing in a highly nonlinear, dispersion-engineered chalcogenide (As2S3) planar waveguide. We achieve error-free, XOR operation for 40?Gbit/s differential phase shift keying (DPSK) optical signals with no power penalty. The effectiveness and broad bandwidth operation of our approach is highlighted by implementing an XOR gate for 160?Gbit/s DPSK signals.     

High speed logic gate using two-photon absorption in silicon waveguides

The switching speed of conventional silicon-based optical switching devices based on plasma dispersion effect is limited by the lifetime of free carriers which introduce either phase or absorption changes. Here we report an all-optical logic NOR gate which does not rely on free carriers but instead uses two-photon absorption. High speed operation was achieved using pump induced non-degenerate two-photon absorption inside the submicron size silicon wire waveguides. The device required low pulse energy (few pJ) for logic gate operation.     

基于高非线性光纤中非线性偏振旋转效应的全光逻辑门研究

提出了一种新型的基于高非线性光纤(HNLF)中非线性 偏振旋转(NPR)效应的全光逻辑门实现方案. 将两路非归零码数据信号A和B以及一路直流光同时注入HNLF, 光功率变化导致的非线性双折射在两个偏振分量上引入非线性相对相移, 从而导致光信号的偏振态旋转. 在HNLF输出端, 通过波分解复用器和偏振分束器同时滤出数据信号和直流光的正交偏振态, 从而同时实现多种基础组合逻辑, 并可以在同一段HNLF中实现较为复杂的半加器、半减器逻辑功能. 理论分析了信号光在HNLF中的偏振态演化, 以及利用HNLF中的NPR效应同时实现多种全光逻辑门的原理. 并在实验中得到了10 Gbit/s全光信号"与”、"非”、"或”、"同或”、"异或”、"A· B”、"A·B”、半加器、半减器等逻辑功能, 验证了方案的可行性.     

Single-SOA-Based Ultrahigh-Speed All-Optical Half Subtracter with PolSK Modulated Signals

A novel ultrahigh-speed all-optical half subtracter based on four-wave mixing (FWM) in a single semiconductor optical amplifier (SOA) is proposed. This scheme only requires a single SOA and two input signals without additional light source, so it is quite simple and compact. Due to the polarization-shift-keying (PolSK) modulated signals being used in this scheme, pattern-dependent degradation can be avoided. By numerical simulation, dependence of the critical factors of the logic gate performance, e.g., the output power of logic 1 and extinction ratio (ER), on two input signals power is investigated. In addition, the effect of the gain polarization dependence of SOA is analysed.     

Design of ultra compact all-optical XOR and AND logic gates with low power consumption

We propose a novel ultra-compact all-optical XOR and AND logic gates without using nonlinear optics. In order to realize these devices, we adopt photonic crystal waveguides (PCWs) based on multi-mode interference devices. Numerical results show that the operating bandwidth of the ON to OFF logic-level contrast ratio of not less than 6.79 dB is 35 nm for XOR logic gate and 9 nm for AND logic gate. Proposed logic gates have the potential to be key components for an optical packet switching system due to their small feature sizes and low power consumption.     

基于光纤四波混频效应的新型组播方法

组播是波长路由光通信网络中的一项重要功能.提出并实验实现了基于高非线性光纤四波混频效应的全光组播方法,将一束载有数据的输入信号光和一束抽运光一起入射到一段高非线性光纤中,通过两个简并四波混频过程产生了两个携带该数据信息的闲频光,从而实现了单一信号的两信道组播,同时抽运光也会受到数据信息的调制.该方法的优点在于组播的实现只需要单一的抽运光源,而不需要再提供其他输入光,结构简单,组播光信号功率均匀、波长可调,并且具有进一步增加组播信道的能力. 关键词： 组播 四波混频 高非线性光纤     

Realization of XNOR logic function with all-optical high contrast XOR and NOT gates

In this article, we propose the realization of XNOR logic function by using all-optical XOR and NOT logic gates. Initially, both XOR and NOT gates are designed, simulated and optimized for high contrast outputs. T-shaped waveguides are created on the photonic crystal platform to realize these logic gates. An extra input is used to perform the inversion operation in the NOT gate. Inputs in both the gates are applied with out of phase so as to have a destructive interference between them and produce negligible intensity for logic ‘0'. The XOR and NOT gates are simulated using Finite Difference Time Domain method which results with a high contrast ratio of 55.23?dB and 54.83?dB, respectively at a response time of 0.136?ps and 0.1256?ps. Later, both the gates are cascaded by superimposing the output branch of the waveguide of XOR gate with the input branch of the waveguide of NOT gate so that it can be resulted with compact size for XNOR logic function. The resultant structure of XNOR logic came out with the contrast ratio of 12.27?dB at a response time of 0.1588?ps. Finally, it can be concluded that the proposed structures with fair output performance can suitably be applied in the design of photonic integrated circuits for high speed computing and telecommunication systems.     

Phase sensitive amplifier for PSK signals based on non-degenerate four-wave-mixing in the optical fiber

A phase-sensitive-amplifier (PSA) using only one pump channel based on frequency non-degenerate four-wave-mixing (FWM) process for phase-shift-keying (PSK) signals is proposed and demonstrated. Theoretical analyses are given first. By optimizing power levels of three channels and parameters of the highly nonlinear fiber (HNLF), the PSA is able to restore the signal fidelity (down to a BER of 10^? 9) as the input signal shows an error-floor with the BER of 10^? 6. Moreover, the PSA for the multi-level PSK signals could be achieved by adjusting the phase relationship between two input signals.     

All-optical XOR logic gate operating on inputs with different modulation formats

An all-optical logic gate which can perform logic exclusive-OR (XOR) between an intensity modulated signal and a phase modulated one, is proposed and numerically investigated. The working principle of this logic gate is based on cross phase modulation in a highly nonlinear fiber.     

All-Optical Logic Device Using Bent Nonlinear Tapered Y-Junction Waveguide Structure

We propose an all-optical logic device made of a bent tapered Y-junction waveguide with a Kerr-type nonlinear interface. It could provide an AND gate, OR gate, and exclusive-OR (XOR) gate. We could obtain different transmission results by adjusting the bending angle. The numerical simulation results show that the device functions as AND, OR, and XOR gates.     

All-Optical Logic Device Using Bent Nonlinear Tapered Y-Junction Waveguide Structure

We propose an all-optical logic device made of a bent tapered Y-junction waveguide with a Kerr-type nonlinear interface. It could provide an AND gate, OR gate, and exclusive-OR (XOR) gate. We could obtain different transmission results by adjusting the bending angle. The numerical simulation results show that the device functions as AND, OR, and XOR gates.     

基于半导体光纤环形腔激光器的新型全光AND门和NOR门

提出了一种新型的基于半导体光纤环形腔激光器(SFRL)中同时发生的四波混频效应和交叉增益调制效应同时实现全光AND门和NOR门方案，并建立了这种全光逻辑门完整的宽带理论模型.通过数值模拟的方法，研究了输入信号光峰值功率及SFRL中两个耦合器的耦合比对这种全光逻辑门输出特性的影响. 关键词： 半导体光纤环形腔激光器 全光逻辑门 四波混频 交叉增益调制     

Silicon photonic crystal all-optical logic gates

All-optical logic gates, including OR, XOR, NOT, XNOR, and NAND gates, are realized theoretically in a two-dimensional silicon photonic crystal using the light beam interference effect. The ingenious photonic crystal waveguide component design, the precisely controlled optical path difference, and the elaborate device configuration ensure the simultaneous realization of five types of logic gate with low-power and a contrast ratio between the logic states of “1” and “0” as high as 20 dB. High power is not necessary for operation of these logic gate devices. This offers a simple and effective approach for the realization of integrated all-optical logic devices.     

All-optical NOT and XOR logic operation at 2.5 Gb／s based on semiconductor optical amplifier loop mirror

All-optical XOR and NOT logic operations based on semiconductor optical amplifier loop mirror (SLALOM) aresimultaneously demonstrated theoretically and experimentally. Based on a segmented semiconductor optical amplifier model, the all-optical logic operation process is simulated theoretically. In an experimental study, 2.5 Gb/s all-optical XOR operation was achieved in the output port of SLALOM, while all-optical NOT operation was achieved in the input port through a circulator at the same time.