基于QD-SOA-XGM的全光逻辑或非门研究

为了改善基于交叉增益调制效应的量子点半导体光放大器全光逻辑或非门的性能,研究了QD-SOA-XGM全光逻辑门的码型效应特性,用两个连“1”脉冲和单个“1”脉冲的峰值功率来衡量,即P30/P20。研究结果表明:第一级输入电流越小,逻辑或非门的性能越好,而第二级输入电流对或非门性能影响很小;在一定范围内,输入连续光功率越大、有源区长度越长、有源区宽度越宽、最大模式增益越大、损耗系数越小,或非门输出效果越好。     

基于量子点半导体光放大器的全光逻辑或门研究

利用量子点半导体光放大器的超快增益恢复特性和交叉增益调制效应,建立了基于量子点半导体光放大器的对称型马赫-曾德尔干涉仪模型,数值实现了对160Gb/s归零码信号的全光逻辑或门运算,并分析了多种系统参数对输出性能的影响。结果表明:一方面,增大注入电流、有源区长度和输入信号光功率均可以提高或门输出信号的Q因子;另一方面,载流子从润湿层到激发态的弛豫时间变短以及较小的线宽增强因子和限制因子也有利于获得较高的Q因子。此外,存在一个最佳的输入信号脉冲宽度使得Q因子的值最大。因此,通过合理优化这些参数值可以大大提高逻辑或门的性能。     

基于QD-SOA交叉相位调制全光逻辑或门啁啾特性的研究

利用马赫-曾德尔干涉仪(Mach-Zehnder Interferometer,MZI)结构实现了基于量子点半导体光放大器(Quantum-Dot Semiconductor Optical Amplifier,QD-SOA)交叉相位调制(Cross-Phase Modulation,XPM)全光逻辑或门。变换光啁啾在一定程度上影响系统的传输性能与输出波形,通过求解跃迁速率方程,建立QD-SOA仿真模型,研究全光逻辑或门的啁啾特性,并仿真分析了有源区长度、背景光功率、脉冲宽度以及注入电流对啁啾的影响。结果表明:有源区长度设置在1.0～2.0 mm、背景光功率设置在小于0 dBm、脉冲宽度设置在1.0 ps左右,QD-SOA-XPM全光逻辑或门的性能较好。     

基于QD-SOA交叉增益调制的波长转换研究

量子点半导体光放大器具有比传统半导体光放大器更快的载流子恢复时间,基于QD-SOA交叉增益调制的波长转换技术具有转换速率快,无pattern effects效应的特点.对有源区长度,输入信号光功率和转化后信号的消光比和脉冲展宽进行了研究,对提高基于QD-SOA交叉增益调制波长转换的性能具有指导意义.     

波分复用-光时分复用波长转换信号的消光比研究

对基于半导体光放大器(SOA)交叉增益调制(XGM)效应的全光波分复用一光时分复用(WDM—OTDM)转换后的两路时分复用输出信号的消光比(ER)特性进行了分析。研究了两路波分复用的输入抽运光和探测光的功率、波长、抽运光的消光比、数据速率以及半导体光放大器的偏置电流、腔长和模场限制因子对转换信号消光比的影响。模拟结果表明，增大抽运光输入功率，选择长波长抽运光，可以增加转换光相应信道消光比，但减小了相邻信道的输出消光比；增加抽运光消光比，可以提高转换光消光比，但各个信道增长幅度不同；减小探测光输入功率，选取短波长探测光波长，增加半导体光放大器的腔长和模场限制因子以及大的偏置电流可提高转换光消光比；对于两路或多路波分复用信号转换时分复用信号的过程中，一定要考虑转换光每个信道消光比的均衡。     

基于级联半导体光放大器中交叉增益调制效应的新型全光逻辑与门

提出一种基于级联半导体光放大器(SOA)中的交叉增益调制(XGM)效应实现的全光逻辑与门新方案。该方案采用单端耦合半导体光放大器提高第一级半导体光放大器输出的消光比，合理控制第二级半导体光放大器的输入光功率，实现了两路2．5Gbit／s非归零(NRZ)信号的逻辑与运算。详细阐明了基于级联半导体光放大器的与门的工作原理和实验方案，分析了实验结果。根据实验结果，发现第一级半导体光放大器输出信号的消光比和信噪比对逻辑与运算结果影响较大，利用单端耦合半导体光放大器后能改善逻辑与运算结果，第二级半导体光放大器的输入抽运光功率对逻辑与运算输出的信号质量有较大的影响。合理控制这些因素，可以有效地提高该逻辑与门的输出特性。     

基于半导体光放大器的超高速全光异或门

传统的基于半导体放大器的全光异或逻辑门,由于受SOA中长载流子寿命引起码型效应的影响,其工作速率的提升受到了限制。提出了一种基于MZI和体材料SOA中交叉增益调制的全光逻辑异或门的工作速率提升的实现方案。通过增加MZI两臂上SOA的长度和提高入射直流探测光功率,增强了直流探测光和数据光在较长的SOA中的相互作用,以减小超高速工作状态下SOA中的载流子寿命,提升体材料SOA的工作速率,实现超高速XOR逻辑功能。研究表明,入射直流探测光功率的提升、SOA长度的增加、数据光峰值功率的提高及数据光脉宽的减少,可使XOR逻辑门的输出信号质量得到明显的提升,使全光异或逻辑门的工作速率可望达到1 Tb/s。     

基于QD-SOA的波长转换特性的消光比研究

在量子点半导体光放大器（QD-SOA）的静态模型基础上,建立了动态模型。讨论了基于QD-SOA的交叉增益调制(XGM)的波长转换特性原理。采用细化分段方法及四阶龙格-库塔法求解速率方程及光场传输方程,给出了变换前后的波形对照。通过改变QD-SOA的自身及外部参数,讨论了输出探测光消光比的影响因素,结果表明增大泵浦光功率、减小探测光功率、增大注入电流及有源区长度都可以增大消光比,从而能够增强信号的抗干扰能力。     

基于半导体光放大器的新型全光逻辑与门

为了实现基于半导体光放大器的全光逻辑与门,采用了在半导体光放大器构成的马赫-曾德尔干涉仪的基础上,注入外部连续光的方法.以半导体光放大器速率方程为基础,对设计方案进行了理论分析和仿真验证,取得了不同重复周期、不同脉冲宽度的光脉冲序列经过全光逻辑与门操作后的输出数据.结果表明,该方案能对传输速率为10Gbit/s或以下的信号进行正确与运算,同时,外光注入可以有效提高半导体光放大器信号处理速度.这一结果对基于半导体光放大器的全光逻辑的设计是有帮助的.     

基于半导体光放大器的新型全光逻辑与门

为了实现基于半导体光放大器的全光逻辑与门,采用了在半导体光放大器构成的马赫-曾德尔干涉仪的基础上,注入外部连续光的方法。以半导体光放大器速率方程为基础,对设计方案进行了理论分析和仿真验证,取得了不同重复周期、不同脉冲宽度的光脉冲序列经过全光逻辑与门操作后的输出数据。结果表明,该方案能对传输速率为10Gbit/s或以下的信号进行正确与运算,同时,外光注入可以有效提高半导体光放大器信号处理速度。这一结果对基于半导体光放大器的全光逻辑的设计是有帮助的。     

All-optical multiple logic gates with XOR, NOR, OR, and NAND functions using parallel SOA-MZI structures: theory and experiment

The authors have proposed, simulated, and experimentally demonstrated all-optical multiple logic gates using two parallel semiconductor optical amplifier (SOA)-Mach-Zehnder interferometer (MZI) structures that enable simultaneous operations of various logic functions of XOR, NOR, OR, and NAND. The proposed scheme, which is optimized by adjusting the optical gain and phase differences in SOA-MZI structures with creative and systematic method, has great merits to achieve the reshaped output pulses with high extinction ratio and enable the high-speed operation at over 10 Gb/s through performance enhancement of SOAs. Its validity is confirmed through simulation and experiments at 2.5 and 10 Gb/s, respectively.     

All-optical logic NXOR based on semiconductor optical amplifiers with the effect of amplified spontaneous emission

The performance of all-optical logic NXOR gate based on semiconductor optical amplifiers Mach-Zehnder interferometer(SOAs-MZI)is simulated.The effects of amplified spontaneous emission(ASE)and the input pulse energy on the system’s quality factor are studied.For the parameters used,the all-optical logic gates using SOAs are capable of operating at speed of 80Gbit/s.     

A novel proposal for all-optical Galois field adder based on photonic crystals

In this paper we are going to propose an all-optical structure for implementing Galois field adder. To do so, we will use four optical XOR gates. The working principle of the proposed structure is based on destructive interference of optical waves. By choosing different lengths for the input waveguides, 180\(^\circ \) of phase difference will be generated between the optical waves. In the final structure, the normalized power for logic 0 and 1 at the output ports was 1 and 45%. Time delay of the proposed structure is about 1.5 ps.     

All-optical XOR gate using semiconductor optical amplifiers without additional input beam

The novel design of an all-optical XOR gate by using cross-gain modulation of semiconductor optical amplifiers has been suggested and demonstrated successfully at 10 Gb/s. Boolean AB~ and A~B of the two input signals A and B have been obtained and combined to achieve the all-optical XOR gate. No additional input beam such as a clock signal or continuous wave light is used in this new design, which is required in other all-optical XOR gates.     

三种基于EDFA的全光逻辑门及其应用

利用掺铒光纤放大器的增益缓变吸收和放大光脉冲信号的特性,结合光纤耦合器和萨格纳克干涉仪,提出了三种的不同结构的全光逻辑门,并分析了此三种全光逻辑门的优缺点和各自的用途。     

Reconfigurable All-Optical Logic Gates for Multi-Input Differential Phase-Shift Keying Signals: Design and Experiments

Differential phase-shift keying (DPSK) signals are promising candidate for the long-haul transmission systems. However, the development of the all-optical signal processing techniques for the DPSK signals is still in its infancy, especially the all-optical logic operations. In this work, a general scheme for reconfigurable logic gates for multi-input DPSK signals with integration possibility is proposed. Benefiting from the optical logic minterms developed by two kinds of optical devices, i.e., optical delay interferometers and semiconductor optical amplifiers (SOAs), target logic functions can be realized by combining specific minterms together. The scheme is reconfigured by changing the phase control of the delay interferometers or the input wavelengths. The latter approach was adopted in the experimental trials. Although the outputs of the scheme are on-off keying (OOK) signals, the data format is compatible with all-optical decision circuits where OOK format is preferred. Two- and three-input experiments are carried out at 20 Gbit/s with nonreturn-to-zero DPSK signals. Various logic operations are demonstrated, including full sets of two- and three-input minterms, AND, NOR, XOR, and XNOR logic operations where the AND and NOR logic are derived simultaneously and the XOR and XNOR logic are convertible. The optical SNR as well as the Q-factor of the two- and three-input results are measured and compared. It shows that the input powers to the SOAs are critical in achieving good extinction ratio and the Q-factor of logic results degrades when several minterms are combined. The recovery time of the SOAs need to be optimized as well. Finally, the scaling issues of the scheme are discussed.     

40 Gbit/s XOR and AND gates using polarisation switching within 1 m-long bismuth oxide-based nonlinear fibre

The implementation of all-optical logic gates of XOR and AND operable at 40 Gbit/s using polarisation switching within only 1 m length of a fabricated Bi-NLF is experimentally demonstrated. The two logic functions are obtained in a single device by simply changing the polarisation states of input signals relative to that of a probe beam.     

Research of all-optical ultra-wideband triplet signal source based on a single semiconductor optical amplifier

A novel scheme for all-optical ultra-wideband triplet signal pulse generation based on the cross-gain modulation (XGM) in a single semiconductor optical amplifier (SOA) is demonstrated. In this scheme, only one optical source and one SOA are needed, so the configuration is simple. Due to only one wavelength is included in the generated triplet pulse, no time difference between output signal light and probe light is introduced during the transmission process. By using the software of Optisystem 7.0, the impacts of the input signal width, the optical power and the wavelength of the optical source on the generated triplet pulse are numerically simulated and studied. The results show that the proposed scheme has better triplet signal pulse when the input signal pulse width is larger, and it is insensitive to the wavelength change within a certain range.