单块晶体2×2光开关

利用晶体的双折射和全内双反射现象以及晶体的电光效应 ,设计了一种单块晶体集成的 2× 2光开关 ,将一个电光调制器和两个光束分束器集成到一块铌酸锂晶体上 ,实现了光束合束、偏振态调制和光束分束三种功能。根据这种光开关的工作原理 ,给出两种开关结构 ,一种是易于级联的垂直入射结构 ,另一种是有较低操作电压的倾斜入射结构 ,并对倾斜入射结构的光开关进行了制作和测试。实验结果表明 :这种集成结构的 2× 2光开关操作电压低 ,串扰小 ,能量损耗小 ,抗干扰 ,稳定可靠 ,适用于各种光学互连网络。     

InP基1×4多模干涉耦合器的设计与制作

在密集波分复用系统中,多波长DFB激光器阵列与多模干涉耦合器集成光源器件具有重要的应用前景.为了研制多波长集成光源中的宽带可用低损耗光耦合器,利用三维有限差分光束传播法仿真设计了一种具有强限制作用的InP/InGaAsP材料的多模干涉型耦合器.输入/输出端波导均采用楔形结构以降低多模干涉型耦合器的插入损耗,提高各个输出端口的出光平衡度.根据仿真结果,结合波导芯层为采用外延生长设备,采用反应离子刻蚀工艺制作了1×乘4多模干涉型耦合器.利用自动对准波导耦合测试系统对所制作器件的插入损耗和出光平衡度进行测量.测试结果表明,该器件在1 550nm波长附近的40nm带宽范围内获得了约2.6dB的通带平坦度,在1 550nm通信波长处,器件的插入损耗低于10dB.     

InP基1×4多模干涉耦合器的设计与制作

在密集波分复用系统中,多波长DFB激光器阵列与多模干涉耦合器集成光源器件具有重要的应用前景.为了研制多波长集成光源中的宽带可用低损耗光耦合器,利用三维有限差分光束传播法仿真设计了一种具有强限制作用的InP/InGaAsP材料的多模干涉型耦合器.输入/输出端波导均采用楔形结构以降低多模干涉型耦合器的插入损耗,提高各个输出端口的出光平衡度.根据仿真结果,结合波导芯层为采用外延生长设备,采用反应离子刻蚀工艺制作了1×乘4多模干涉型耦合器.利用自动对准波导耦合测试系统对所制作器件的插入损耗和出光平衡度进行测量.测试结果表明,该器件在1 550 nm波长附近的40 nm带宽范围内获得了约2.6 dB的通带平坦度,在1 550 nm通信波长处,器件的插入损耗低于10 dB.     

Gain-Flattened Optical Limiting Amplifier Modules for Wavelength Division Multiplexing Transmission

By integration of a bidirectional erbium-doped fiber amplifier and a three-port optical circulator with several fiber Bragg gratings (FBGs), two gain-flattened optical limiting amplifier (OLA) modules are proposed and experimentally demonstrated. They rely on the use of central wavelength misalignment and bending loss methods, respectively. They can effectively cover the whole useful 1.55-mum band. Both modules can provide gain-flattening characteristics over a large input dynamic range. The FBGs integrated OLA configuration has potential application in wavelength division multiplexing lightwave communication systems.     

数值模拟二维间隙表面等离子波导传输特性

利用表面等离子激元的新颖特性,设计了二维间隙表面等离子波导.以这种结构为基础通过变形和组合形成90°直角弯曲波导、T型光功率分配器和光开光,采用时域有限差分法研究了它们的传输特性.结果表明:不同于介质光波导的弯曲损耗来自于辐射泄漏,90°直角弯曲间隙表面等离子波导的能量损耗主要来自于金属中的欧姆热损耗.在间隙达到40 nm以上后,当直行段的长度适当时,弯曲段的透射率较相同长度的直波导的透射率要大.T型光功率分配器在两输出波导的间隙宽度比达到0.6及以上时,不同于传统介质波导的分光原则,能量主要沿等效折射率较小的输出臂流出.当两输入光的相位反相时,T型光开关处于输出截止的状态,当两输入光的相位同相时,T型光开关处于输出导通的状态.所有波导间隙均小于衍射极限,实现了超衍射极限传播,可用于未来了超大规模集成光路中.     

X波段叠层片式微带铁氧体环行器的设计

采用叠层片式化设计有望实现微波环形器与低温共烧陶瓷(LTCC)技术的结合。借助三维电磁仿真手段设计了一种X波段微带铁氧体环行器,基片采用具有不同饱和磁化强度的旋磁材料构成叠层片式结构。研究结果表明,叠片数目及其饱和磁化强度的搭配对环形器的回波损耗和隔离度特性影响显著,这与叠层结构引入的界面及叠片变化的饱和磁化强度影响了环形器的等效输入电路参数有关。通过优化设计,可以获得具有高回波损耗、高隔离度及低插入损耗等优良性能的器件,但带宽受叠片数目及其饱和磁化强度的搭配影响较小,难以通过优化进行拓展。     

Monolithically integrated bacteriorhodopsin-GaAs/GaAlAs phototransceiver

A monolithically integrated bacteriorhodopsin-semiconductor phototransceiver is demonstrated for the first time to the authors' knowledge. In this novel biophotonic optical interconnect, the input photoexcitation is detected by bacteriorhodopsin (bR) that has been selectively deposited onto the gate of a GaAs-based field-effect transistor. The photovoltage developed across the bR is converted by the transistor into an amplified photocurrent, which drives an integrated light-emitting diode with a Ga0.37Al0.63As active region. Advantage is taken of the high-input impedance of the field-effect transistor, which matches the high internal resistance of bR. The input and output wavelengths are 594 and 655 nm, respectively. The transient response of the optoelectronic circuit to modulated input light has also been studied.     

A high efficiency 46 to 92 GHz all microstrip frequency doubler

Using packaged GaAs varactor diodes, a high efficiency 46 to 92 GHz frequency doubler has been developed. Microstrip circuits have been used to match the input and output impedances presented by the diode. A conversion loss of 8 to 10 dB was measured. This doubler circuit is useful for W-band (75 to 110 GHz) integrated circuit receivers and transceivers. The use of microstrip circuit can drastically reduce the fabrication cost in addition to size and weight.     

双极集成电路低剂量率辐射损伤增强效应的高温辐照加速实验

选择了四种典型双极集成电路,在两种不同剂量率下,开展了不同温度的高温辐照加速实验,测量了典型双极集成电路的辐射敏感参数在不同高温辐照下的变化规律。实验结果表明:高温辐照能够给出空间低剂量率辐射损伤增强效应的保守估计,且存在最佳辐照温度,最佳辐照温度随总剂量的增加向低温区漂移,随剂量率的增大向高温区漂移,在相同剂量率和总剂量下,输入级为NPN晶体管的双极集成电路比输入级为PNP晶体管的最佳辐照温度低。     

Active structural acoustics control of beams using active constrained layer damping through loss factor maximization

Vibration and acoustic control of beams with classical boundary conditions using active constrained layer damping is presented. The control input that maximizes the loss factor of the active constrained layer damping is determined through taking the first variation of the loss factor with respect to the control input. Although the loss factor is a positive definite quantity, the first variation yields control input that maximizes the factor. The resulting control input significantly reduces the vibration and acoustic response of the beams at their resonant frequencies.     

低插损平坦谱响应阵列波导光栅解复用器优化设计

通过在输入波导与输入平板波导之间加入一种模式转换结构,获得了一个具有平坦光谱响应,低插损,光谱响应对称的阵列波导光栅型波分复用器,该模式转换结构由一个与输入波导的输出端连接的第一锥形波导,一个与此锥形波导输出端连接的细直波导,一个与细直波导输出端连接的第二个锥形波导以及一个连接输入平板波导和第二个锥形波导的梯形波导组成,通过优化设计梯形波导和第二个锥形波导的形状可以获得较宽的1dB通带带宽和较低的插损,同时光谱响应具有非常好的平坦性,而且通过对第一个锥形波导和细直波导的优化设计,在不引入明显的额外插损的条件下,能大大减小由于输入波导的弯曲引入的光谱响应的不平坦.     

C波段相对论速调管放大器3维整管模拟研究

 建立了带输入、输出波导结构的C波段相对论速调管放大器3维整管模型,利用3维软件对其高频特性进行了数值计算研究,对整管结构进行了优化设计。并用3维PIC程序对电子束经过输入腔后的束流调制、注入微波的吸收情况、中间腔对束流的调制以及输出腔后微波提取情况进行了模拟研究。模拟结果表明：输入腔与微波注入波导匹配较好,注入微波能被电子束和谐振腔很好吸收,在输入腔间隙后20 cm处得到了11%的基波电流调制深度;在中间腔后15 cm处得到了约76%的基波电流调制深度;在中间腔后电流调制最强处加上输出腔,提取到800 MW的输出微波,效率26%。     

Integrated Image Associative Memory and Its Optical Implementation

We present the concept of integrated processing to combine intuitive processing of neural networks with logical processing of the conventional digital computer. We investigate a way to embody the concept in the neural network system by introducing external constraints in terms of external input. The effect of the external input is analyzed using the generalized projection method. The concept of integrated processing is applied to an image associative memory system, and the system is optically implemented for high-speed parallel processing incorporating it with the computer. The experimental result is presented to illustrate the effectiveness of the external input to control the output of the image associative memory.     

Passive T-bus with asymmetrical 4-port couplers

A newly designed 4-port coupler in planar technology is described. The axes of the coupling fibers are mutually offset as before, but the input fiber is thinner than the other three, and its diameter is matched to the emitting surface area of the light source serving as a transmitter. Low insertion loss and high coupling efficiency are realized through the choice of favorable dimensions. Graphs show the output coupling efficiency, input coupling loss, and insertion loss with step-index fibers as a function of the axial offset. The maximum number of terminals that can be connected to the T-bus is calculated for various conditions. The number of terminals is found to be about 40% higher than is possible with the coupler with four identical fibers.     

10~45 GHz宽频段同轴输入窗设计

为满足微波管放大器对宽频段输入窗的需求,并保证馈源的真空密封需求,提出并设计了一种适用于宽频段微波放大器的同轴输入窗。该宽频段同轴输入窗采用渐变圆环形陶瓷,材料介电常数为9.3,窗片厚度为2.5 mm, 内径为2.14 mm,外径为5 mm,渐变段长度为6.5 mm。利用三维高频电磁仿真软件CST对其建模分析,并对同轴内外结构尺寸和陶瓷渐变结构进行优化仿真,得出该宽频带同轴输入窗能够在10～45 GHz频带内实现插入损耗小于0.5 dB。     

考虑入射光场光谱分布和损耗的Fabry-Perot干涉仪透射函数

运用部分相干光理论,分析了多光束干涉,得到了考虑损耗和入射光光谱函数分布的Fabry-Perot干涉仪透射函数。并就损耗和入射光场光谱宽度对透射函数的透过峰高度、对比度、精细常数,即Fabry-Perot干涉仪的性能的影响做了分析、讨论。     

Passive T-bus with asymmetrical 4-port couplers

Abstract

A newly designed 4-port coupler in planar technology is described. The axes of the coupling fibers are mutually offset as before, but the input fiber is thinner than the other three, and its diameter is matched to the emitting surface area of the light source serving as a transmitter. Low insertion loss and high coupling efficiency are realized through the choice of favorable dimensions. Graphs show the output coupling efficiency, input coupling loss, and insertion loss with step-index fibers as a function of the axial offset. The maximum number of terminals that can be connected to the T-bus is calculated for various conditions. The number of terminals is found to be about 40% higher than is possible with the coupler with four identical fibers.     

Proposal for loadable and erasable optical memory unit based on dual active microring optical integrators

A novel approach for loadable and erasable optical memory unit based on dual microring optical integrators is proposed and studied. The optical integrator, which can generate an optical step function for data storing, is synthesized using active media for loss compensation and a tunable phase shifter for data reading at any time. The input data into the memory is return-to-zero (RZ) signal, and the output data read from the memory is also RZ format with a narrower pulse width. An optical digital register based on the proposed optical memory unit is also investigated and simulated, which shows the potential for large scale data storage and serial-to-parallel data conversion. A great number of such memory units can be densely integrated on a photonic circuit for future large scale data storage and buffer.     

Optical clock distribution using integrated free-space optics

The design and experimental results of an optical clock distribution system based on integrated free-space micro-optics are reported. Planar optical components such as lenses, beamsplitters, and mirrors, are monolithically integrated on a single glass substrate to provide a stable and compact system. A single input beam is split and distributed evenly to N output positions using a binary tree of beamsplitters. The experiment shown demonstrates the principle idea for a system with a fanout of eight. Theoretical considerations show that a fanout of 64 or larger is feasible.     

Electro-Optic Polymer Integrated Optic Devices and Future Applications

Recent developments in electro-optic polymer materials and devices have led to new opportunities for integrated optic devices in numerous applications. The results of numerous tests have indicated that polymer materials have many properties that are suitable for use in high-speed communications systems, various sensor systems, and space applications. These results, coupled with recent advances in device and material technology, will allow very large bandwidth modulators and switches with low drive voltages, improved loss, long-term stability, and integration with other microelectronic devices such as MEMS. Low drive voltage devices are very important for space applications where power consumption scales as the square of the modulator half-wave voltage. In addition, we have demonstrated novel dual polymer modulators for mixing RF signals to produce sum and difference frequency modulation on an optical beam. This novel approach allows the suppression of the modulation at the two input RF signals, and only the mixing signals remain superposed on the optical beam. The dual modulator can be used for various encoding/decoding and frequency conversion schemes that are frequently used for both terrestrial and space communications. Another application of polymer integrated optics is in the field of optical sensing for high-frequency (GHz) electric fields.