Cross-phase modulation in one-dimensional photonic crystals: applications to all-optical devices

We present a numerical study of a finite photonic band gap structure with a χ⁽³⁾ nonlinearity that couples two input pump beams at frequencies ω₁ and ω₂. We show that in this configuration a variety of all-optical devices can be obtained: an optical transistor, a double switch, and a dynamical switch.     

Low electric power drived thermo-optic multimode interference switches with tapered heating electrodes

A novel thermo-optic multimode interference (MMI) switch with a tapered heating electrode was proposed and the performance of the switch was simulated. An analytical steady-state heat-conduction model is also presented. In the design, one tapered heating electrode is used to alter the refractive index in the multimode slab region to realize the switching function. The simulation results indicate that the MMI switch can provide high extinction ratio, and good polarization- and wavelength-independence. The electric power consumption for the MMI switch is half of that of a switch with a straight heating electrode and similar to that of a Mach-Zehnder interferometer switch.     

600 kJ供能系统及其在轨道炮中的应用

 本文介绍了一种适合于电磁轨道炮使用的600 kJ供能系统。初级能源是电容器组。经过短路开关和电感储能线圈组成的转换电路，把能量输送给轨道炮。系统的主控开关和短路开关是金属接触型固体介质爆炸开关。本文推荐了一种爆炸开关闭合电阻随时间变化的经验模型。这套供能系统经过实验证明，它运行可靠、性能稳定。     

Pseudo spin-valves with Al or Nb as spacer layer: GMR and search for spin switch behaviour

The magnetoresistance of several Ferromagnet/Normal metal/Ferromagnet spin-valve type structures has been investigated using Al as normal spacer layer. A magnetoresistance ratio up to 4.1% at room temperature and 5.7% at 0.3 K is found for the sandwich with both Co layers, while slightly lower signals are found for the structures involving CoFe and NiFe layers. The magnetoresistance dependence for Co/Al/Co, Co/Al/CoFe and Co/Al/NiFe on the spacer layer thickness exhibits the familiar non monotonic behaviour with second peak slightly larger than the one reported for Cu based pseudo spin valves. At cryogenic temperatures, preliminary results on the onset of spin switch effects in Co/Al/Co and the full spin switch effect in Co/Nb/Co are also reported here.     

Simulations of the phonon Bragg switch in GaAs

It has recently been proposed that X-rays can be switched on sub-picosecond time-scales by using laser-generated coherent optical phonons: The so called phonon Bragg switch. We present here detailed simulations of the effficiency of such a switch by solving the time-dependent generalized Takagi-Taupin equations utilizing a perturbative approach. We explore the switching efficiency in diffraction from the (004) planes of GaAs as a function of both excited phonon wave vector and amplitude.     

Magnetic and electronic properties of the antiferromagnetic YbFe4Al8 compound

The magnetic, electrical and electronic properties of the tetragonal ternary YbFe₄Al₈ compound have been investigated. This compound was supposed to be an antiferromagnetic superconductor due to the negative magnetization signal appearing at a low field of the field cooling mode, however, based on the measurements of the temperature dependence of magnetization and resistivity we do not confirm the presence of superconductivity in this material and we ascribe the negative magnetization to the complicated non-collinear magnetic structure. A switch to the antiferromagnetic order at about 150 K has been visible both on the M(T) and ρ(T) curves. The valence state of the Yb ions has been studied by X-ray photoemission spectroscopy. The valence band spectrum at the Fermi level exhibits the domination of the hybridized Yb(4f) and Fe(3d) states.     

An Easily Operating Polymer 1×4 Optical Waveguide Switch Matrix Based on Vertical Couplers

A three-dimensional （3D） polymer thermo-optic （TO） 1 × 4 waveguide switch matrix based on vertical couplers is demonstrated. It consists of four basic 3D switch units and because of its 3D structure, its construction is compact, only 9 mm in length; moreover, the control logic of the entire switch is very simple, the light signal can be easily switched to any output port by operating only a single switch unit. The finished devices exhibit a switching extinction ratio greater than 21 dB for all of four output ports and the crosstalk between two adjacent output ports is lower than -19 dB. The rise time and the fall time of the switch matrix are 0.8ms and 1.4ms, respectively. The required electrical power to initiate the switching function for M1 switching units is about 50mW.     

Investigation of passively synchronized dual-wavelength Q-switched lasers based on V:YAG saturable absorber

In this paper the results of a theoretical and experimental investigation of synchronized passive Q-switching of two Nd:YVO₄-based solid-state lasers operating at two different wavelengths, is described. A V:YAG saturable absorbing material was used as a passive Q-switch performing the synchronization of the two laser fields. This material provides Q-switching operation at both 1064 and 1342 nm wavelengths simultaneously, saturating the same energy level. By adjusting the pump power of both lasers, it was possible to optimize the overlap of the two pulse trains and to switch between different states of synchronization. A theoretical model based on rate equations, which has been developed in order to investigate optical performance of the laser system, is in a good agreement with the experimental results. The principle of synchronized Q-switching can lead to new, pulsed all-solid-state light sources at new wavelengths based on sum-frequency mixing processes.     

Optical Switching in Silicon Nanowaveguide Ring Resonators Based on Kerr Effect and TPA Effect

We analyze theoretically the 1 × 2 low-power all-optical switching in silicon nanowaveguide ring resonators （RR） based on the Kerr effect and two-photon absorption （TPA）, and give a comparison between both the all-optical switches. The calculation shows that the switching power of the TPA-RR switch is 3 orders smaller than that of the Kerr-RR switch. The switching time for both the switches is about 100ps.     

稳态锁模产生4ps激光脉冲

首次利用ＧａＡｓ光电导开关，控制Ｎｄ：ＹＬＦ激光器腔内Ｑ值，实现稳态锁模，获得脉宽和能量稳定性极高的４ｐｓ激光脉冲。     

Magnetically Tunable Terahertz Switch and Band-Pass Filter

A novel design of a tunable terahertz switch and band-pass filter using liquid-crystal-filled photonic crystal waveguide is demonstrated. The effects of magnetic field on the photonic bandgaps and transmitting properties of a THz wave are investigated by using the plane wave expansion method and finite difference time domain method. The efficient photonic bandgap tuning is predicted such that the two-dimensional liquid-crystal-filled photonie crystal waveguide can serve as a switch and continuously tunable band-pass filter with controlling of the magnetic field.     

High Repetition Rate Miniature Triggered Spark Switch

A miniature triggered spark switch designed to operate at high repetition rates has been constructed. The device, along with associated triggered circuitry, has been incorporated into a simple LC generator which produces an oscillatory discharge at a frequency of 150 MHz. The switch is operated in the pressure range 760 torr-2.6 × 103 torr using commercial dry nitrogen as the working gas. Both brass (70/30) and aluminum (99.95 percent) electrodes were investigated for repetition frequencies as high as 20 kHz and for gas flow rates as high as 8 cm3/s. The effect of repetition rate on switch jitter and switch breakdown voltage is presented and discussed in terms of gas pressure and flow rate.     

PTS装置脉冲输出开关

出于开关性能参数和结构要求考虑,PTS装置脉冲输出开关设计为3对自击穿电极间隙的水介质开关,间隙结构采用板-球间隙的同轴-三平板结构。选择水介质自击穿开关作为研究对象,进行了1.5 MV同轴结构开关研究,并在此基础上开展了4 MV同轴-三平板结构开关研究。开关实验达到的技术指标为:自击穿电压3.5 MV,导通电流500 kA,电感65 nH,自击穿时间分散性极差4.0 ns（1.3 ns均方根值）。     

Ab initio investigation of the I-V characteristics of the butadiene nano-molecular wires: A light-driven molecular switch

We apply a first-principles computational approach to study a light-sensitive molecular switch. The molecule that comprises the switch can convert between a trans and a cis configuration upon photoexcitation. We find that the conductance of the two isomers varies dramatically, which suggests that this system has potential application as a molecular device. A detailed analysis of the projection of the density of states (PDOS) and the transmission coefficients T(E) of the system reveals the mechanism of the switch.     

1,3-diphenyltriazene as a possible optical molecular switch: A first-principles study

By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of a 1,3-diphenyltriazene-based optical molecular switch. The molecule that comprises the switch can convert between the cis and the trans forms upon photoexcitation. The transmission spectra of two forms are remarkably distinctive. Theoretical results show that the current through the trans form is significantly larger than that through the cis form, which suggests that this system has attractive potential application in future molecular switch technology.     

无冲突4端口榕树开关网络的实验研究

提出了一种新型的无冲突４端口榕树型开关网络。采用液晶列阵及偏振棱镜、三角棱镜、波片等光学元件，在光学上实现了这种网络，得到了由４端进到４端出的２４种全排列方式。     

Transverse optical patterns for ultra‐low‐light‐level all‐optical switching

We review recent theoretical and experimental efforts toward developing an all‐optical switch based on transverse optical patterns. Transverse optical patterns are formed when counterpropagating laser beams interact with a nonlinear medium. A perturbation, in the form of a weak switch beam injected into the nonlinear medium, controls the orientation of the generated patterns. Each state of the pattern orientation is associated with a state of the switch. That is, information is stored in the orientation state. A realization of this switch using a warm rubidium vapor shows that it can be actuated by as few as 600 ± 40 photons with a response time of 5 µs. Models of nonlinear optical interactions in semiconductor quantum wells and microresonators suggest these systems are also suitable for use as fast all‐optical switches using this same conceptual design, albeit at higher switching powers.     

SOI无间距定向耦合光开关模型分析及设计

提出了一种简便可行的ＳＯＩ无间距定向耦合光开关（ＢＯＡ型－Ｂｉｆｕｒｃａｔｉｏｎ Ｏｐｔｉｑｕｅ Ａｃｔｉｖｅ）模型分析方法，采用等离子体色散效应这种光开关的电学调制机理；而用ｐｎ结大注入效应分析开拳电学性质；并根据大截面单模ＳＯＩ脊形波导理论和上棕分析，设计了利用双模干淑机制工作的这种器件的结构参数和电学参数。     

Design and simulation of a novel 32 × 32 photonic bandgap power switch based on SOI waveguide

In this paper, we propose a novel 32 × 32 photonic bandgap (PBG) power switch based on silicon-on-insulator (SOI) substrate. The 32 × 32 PBG power switch merges the design concept of PBG structure and multimode interference (MMI) structure. With controlling the voltages of 256 blocks for changing the refractive index, we can demonstrate that the light propagation direction can be switched to the assigned output port as a 32 × 32 power switch. According to the simulations, the power switching control tables are searched and selected for successful switching. The size of our designed 32 × 32 PBG switch can be reduced to 252 × 6040 μm which is much smaller than the conventional opto-electronic switches.     

快前沿直线脉冲变压器驱动源多间隙气体开关

进行了一种可用于快前沿直线脉冲变压器驱动源系统的多间隙气体开关的设计和实验,给出了开关的静态放电实验结果,获得了静态击穿电压平均值及标准偏差随气体压强的变化规律。开关充0.15 MPa干燥空气时,最高耐压可以达到200 kV。研究了开关在不同欠压比和不同触发脉冲幅值下的触发特性。开关工作电压150 kV、欠压比78.5%、触发电压70 kV时,开关的触发延迟时间34.4 ns,抖动1.6 ns。开关经过5 000余次放电,击穿点分布均匀,可以形成多通道放电。开关结构新颖,安装操作简便,装配精度大大提高,实用性强。