基于亚波长金属孔阵列的光控太赫兹强度调制器

太赫兹波强度调制器对太赫兹技术的发展至关重要。亚波长金属孔阵列可以激发表面等离子激元,增加入射电磁波的透射效率,极大地提高调制器的调制深度。提出了一种基于表面等离子激元的光控太赫兹波强度调制器。首先给出了器件所依赖的基本原理;其次利用传统的微纳加工技术在半绝缘砷化镓衬底上制作出二维亚波长金属孔阵列;最后搭建了太赫兹时域光谱系统,测试了器件样品对太赫兹波的透过率。结果表明:亚波长金属孔阵列可以引起透射率的异常增强,且透射率随着泵浦光强的增大而减小,在特定频率点实现了较高的调制深度。此研究为实现高调制深度的太赫兹波强度调制器提供了参考。     

High-frequency InGaAs/InP multiple-quantum-well buried-mesa electroabsorption optical modulator

We describe the structure and performance characteristics of an InGaAs/InP multiple-quantum-well (MQW) electro-absorption buried-mesa optical modulator. The device is fabricated with two metal-organic chemical-vapour-deposition (MOCVD) growth steps, wherein small-area circular (40?m diameter) PIN diodes are buried with Fe-doped semiinsulating (SI) InP regrowth. The modulator has a relatively low insertion loss (4.5 dB) with 25% modulation depth and very high modulation bandwith (5.3 GHz) operating at 1.62?m wavelength.     

Compact, low-crosstalk, and low-propagation-loss quantum-well Y-branch switches

We demonstrate a quantum-well Y-branch switch designed for low crosstalk, low propagation loss, and compact size. The active waveguide core is composed of InGaAsP-InP quantum wells for reverse-bias electrorefractive switching. We achieve -20-dB crosstalk and 2-dB/cm propagation loss with a 2-mm-long switch.     

基于石墨烯的太赫兹波调制器

石墨烯由于其优异的电学性能,在微波、毫米波、太赫兹波等领域显示出潜在的应用前景。本文设计了毫米波和亚太赫兹波频段的基于石墨烯的相位和幅值波导调制器。该石墨烯调制器可以通过调节石墨烯的表面阻抗来调控电磁波在波导中传播的振幅和相位;分析了石墨烯片的长度和位置对电磁波在波导中的透射和反射系数的影响,同时还分析了石墨烯化学势对电磁波在波导中传输和反射的影响。结果表明,通过调节石墨烯片的长度及其在矩形金属波导中的位置,可以调控调制器的反射系数、透射系数和透射相位调制范围,并满足器件级应用需求。     

Polarisation-independent intensity modulator based on lithiumniobate

Broadband, polarisation-independent intensity modulation based on a lithium niobate phase modulator in a fibre Sagnac interferometer configuration is demonstrated. Residual polarisation dependence is found to be as low as <0.25 dB for low frequency operation, and <2 dB to frequencies of >20 GHz     

High-frequency modulation of a quantum-cascade laser using a monolithically integrated intracavity modulator

We report a quantum-cascade laser monolithically integrated with an intracavity modulator which could be operated up to 1 GHz. In contrast to earlier approaches, where the radio frequency (RF) modulation signal was supplied to the entire cavity length of the laser structure, we drive only a relatively small 375-/spl mu/m-long section of the cavity. At the same time, a quasi-continuous-wave signal was supplied to the remaining 1125-/spl mu/m-long section. This modulation scheme resulted in smaller parasitic capacitance effects than what we reported previously, and enabled us to work with lower RF voltages and currents.     

A novel optical phase modulator design suitable for phased arrays

A new design of optical phase modulator in SIMOX has been demonstrated, which allows duplication of active waveguides with a minimum requirement for external contacts and metallization. The device is based on a common cathode configuration and requires 56.5 mA at 1.65 V to produce a π-phase shift. To confirm the experimental results, the same device structure has been modeled, and provided good agreement, with V_π calculated to 1.70 V and 52.6 mA     

基于IGBT的固态脉冲调制器设计

基于课题建设的需要,需对某型雷达脉冲调制器进行固态化改造,为达到经济省时的目的,采用了设计与仿真的方法。应用新型功率开关器件IGBT替代电真空器件,设计了单片机控制的固态脉冲调制器,克服了雷达脉冲调制器中广泛采用的电真空器件的局限性。Simulink仿真结果表明,调制波形及功率完全满足雷达的战术技术指标。得出了所设计的固态调制器可以工程化的结论。     

THz modulator based on the Drude model

An amplitude modulator for the terahertz (THz) range is designed. The Drude model is adopted, in which the collision damping is independent of the carrier energy. The Si block with 808 nm laser is illustrated, and it will generate the photocarriers. The injected photo-carriers will change the conductivity and dielectric of the sample, which have direct relationship with the absorption coefficient of the THz wave, hence to control the characteristics of the THz wave in the sample. By changing the light intensity, due to the different photon-generated carrier concentrations, the single transmission of the THz wave in the silicon substrate is changed remarkably.     

一种基于相位调制环的WDM-PON

本文首先简单介绍了WDM-PON的技术背景,在此基础上分析WDM-PON的劣势为造价成本高,通过对现存关键技术的研究和对比,提出了一种基于相位调制环的多波长产生器,将这种技术应用于WDM-PON中,大大降低了成本。     

Integrated optical detector array, waveguide, and modulator based on silicon technology

An integrated optical (IO) hybrid circuit consisting of a photodetector array, waveguide, and acousto-optic modulator on a common silicon substrate has been fabricated. This IO hybrid circuit is a major step in the development of a combination optical-electronic processing system. In this device an array of p-n junction photodiodes was fabricated on a 2-in silicon wafer and a 7059 glass waveguide film sputtered over an SiO/SUB 2/ insulating layer on the wafer. Another SiO/SUB 2/ layer was deposited under the transducer electrode. The transducer was a 40-MHz lithium niobate rotated Y-cut crystal. A prism was used to couple in the light beam from a 5 mW He-Ne laser. The guided light beam was directed at one of the diodes in the array and pulsed RF signals were applied to the transducer. Oscillator frequencies of 40 MHz and 120 MHz were separately applied. Modulation depths of greater than 25 percent were produced. The fabrication of the optical guide photodiode and electrical interconnections on a single silicon wafer utilized standard IC fabrication techniques.     

High-frequency electrical properties of a vertical-cavity surface-emitting laser with a monolithically integrated electro-optical modulator

The high-frequency electrical properties of a vertical-cavity surface-emitting laser with a monolithically integrated electro-optical modulator are studied using small-signal modulation analysis of the electroreflectance. The experimental data obtained are approximated using the suggested equivalent electrical circuit, which accounts for the formation of a nonequilibrium space charge in the carrier-depletion region of the modulator. The bandwidth of the high-frequency electrical-signal transfer to the electro-optical region, determined for the suggested equivalent electrical circuit of the modulator, is shown to be 3GHz.     

基于AD9954的多模式调制器的设计

AD9954是采用先进的DDS技术生产的高集成度频率合成器,通过对幅度、频率、相位的编程来生成不同的信号.本方案以AD9954为核心设计平台,通过FPGA和单片机的控制,设计了一种功能齐全、性能优良的调制器.对所产生的信号作了理论分析,并阐述了该调制器的系统结构、软硬件设计和具体电路实现.本方案不仅能生成正弦波、方波和三角波,还能生成AM、FM、ASK、FSK、PSK、4PSK、线性扫频等通信中的各种信号,且具有更精确的输出频率和更高的稳定度,可以满足不同环境、不同条件下通信方式的需求.     

基于FBG的电光调制器电极设计

电光调制器作为光通信系统中最重要的器件之一,其性能决定了光通信系统的传输性能,而电光调制器的电极结构、种类和设计都对调制器的性能有重要的影响。针对基于光纤布拉格光栅(FBG)的新型电光调制器电极展开了研究和设计,并通过数值计算方法,对模场重叠因子、电极结构参数以及模场重叠因子和FBG中心波长漂移量 的关系做了讨论,并由此对基于FBG的聚合物电光调制器的电极做了一系列的分析和研究。文中的研究对基于FBG的电光调制器的制作具有一定的指导意义,能够促进电光调制器的发展。     

基于现代DSP技术的QPSK调制器的设计

为了提高DSP系统的开发效率,引入了现代DSP技术,并由此设计了QPSK调制器.依据QPSK调制的基本原理,利用MATLAB/Simulink DSP Builder和QuartusⅡ搭建模型,在模块的形成方式上,采用DSP Builder中的模块代替VHDL编程,在同一平台上实现了系统建模和硬件实现的有机结合,然后利...     

一种扩频通信调制器的FPGA设计与仿真

本文首先介绍了 FPGA的设计思想及流程,然后以一种扩频通信调制器为例,描述了如何实现自顶向下的设计,并重点分析了PN码产生器模块的设计及仿真过程     

基于硅基等离子超表面的可调太赫兹调制器

由于硅对太赫兹的调制效果较差,所以从理论上和实验上研究了基于硅基等离子诱导透明(PIT)超表面的太赫兹调制器。研究结果发现在透射光谱中可以观察到明显的透明窗口,该透明窗口是由2个谐振器之间的近场耦合引起的。实验结果表明,随着泵浦光功率的增加,透明窗口出现了蓝移。当光泵功率从0 m W增加到700 m W时,0.70 THz处的振幅调制深度可以达到80.75%,同时研究了它的慢光效应。设计的这种新型的超表面结构增强了硅的调制效果,提供了一种实际应用的可能。     

Integrated optics waveguide modulator based on surface plasmonresonance

A modulator with micron dimensions, capable of optical modulation and switching in an integrated waveguide, is proposed. The proposed modulator uses surface plasmon resonance and an electro-optic polymer to modulate light which is guided in an integrated waveguide. Theoretical analysis of the modulator is presented for wavelengths of light in the visible and near infrared. Design criteria and dimensions of the modulator are discussed     

采用双平行马赫曾德调制器的四倍频信号产生

采用了一种基于双平行马赫曾德调制器（DPMZM）产生四倍频微波信号的方法。理论分析了微波四倍频的基本原理,双平行马赫曾德调制器的上臂子MZM加载射频信号,且上臂子MZM工作在最大传输点,下臂子MZM直通光载波,使DPMZM最终工作在载波抑制的偶次边带调制模式,结合光学带通滤波器滤除高阶杂散边带,提升四倍频信号的纯净度。搭建了基于双平行马赫曾德调制器的四倍频微波光子链路,并对四倍频系统的性能进行测试,实验结果表明系统的光边带抑制比和射频杂散抑制比分别达到了21.09 dB和28.41 dB。由于链路未引入额外的电子器件,系统可以产生高达80 GHz的微波信号。基于双平行马赫曾德调制器产生四倍频微波信号的方法结构简单,易于控制,具有良好的倍频性能,可实现高纯净度和高频率的四倍频信号的产生。     

Polymeric digital optical modulator based on asymmetric branch

A digital optical modulator based on an asymmetric Y-branch waveguide is proposed and fabricated by using an electro-optic polymer. The operating point is initially shifted to the off-state utilising the asymmetry in the branch to provide an initial zero-state with no electrical bias. It has been confirmed that the high extinction ratio can be obtained with a low drive voltage. An extinction ratio of 25 dB is demonstrated for a drive voltage of 20V using a polymer PMMA-DR1 with r_ss of 5 pm/V at 1.3 μm