Open-loop electrooptic sampling for real-time analysis and near-field imaging of ultrafast electronic devices

In this paper, we present an open-loop electrooptic sampling system for real-time characterization and near-field scanning of ultrafast electronic devices. The system capabilities such as picosecond time resolution as well as 210 GHz of measurement bandwidth are verified with measurement of a CMOS nonlinear transmission line and an ultimate bandwidth of 230 GHz has been achieved with a post-process algorithm. The noise of the system is quantified and imaging over a broad range of frequencies for an on-chip antenna is demonstrated.     

研制超宽带全光取样示波器设备

全光取样示波器是研究与开发超高速光通信系统和光子交换网络的关键性测试仪器设备. 本文简介了我们自行设计和研制出的超宽带全光取样示波器设备的实验样机系统, 并报道了我们已取得的初步实验结果. 采用自主研发的高稳定性被动锁模飞秒光纤激光器作为该光学示波器的光脉冲取样源, 我们通过利用高度非线性光纤中的四波混频效应, 成功地实现了对脉宽为1.8ps、重复频率分别为10GHz和40GHz的光脉冲信号的全光取样. 然后通过数字信号处理和计算机图形处理, 得到了再现后的超短光脉冲信号波形, 并测出了其脉冲宽度值为2.3ps. 借助于该光学取样示波器实验样机, 我们还成功地完成了对脉宽为1.8ps、经过伪随机数据序列调制后的10Gbit/s和40Gbit/s光数据信号眼图的精确测量. 这是我国首次报道有关超宽带全光取样示波器设备的实际研制工作及其相应的实验测试结果. 所得到的有关超短光脉冲信号波形的测试结果也与用70GHz宽带电子示波器和超快光电探测器组成的常规光电测量系统所获得的结果进行了比较, 清楚地表明了我们研制出的全光取样示波器实验样机比后者具有更高的时间分辨率和更大的测量带宽.     

基于双音外差的电光相位调制器半波电压自校准测量方法

电光相位调制器是光纤通信系统、微波光子系统和相干光通信系统中的关键器件之一. 作为器件本征参数, 电光相位调制器的半波电压通常利用光谱方法和电谱方法进行测量. 光谱方法受到光源线宽和光谱仪分辨率限制, 测量的分辨率较低; 电谱方法则需要光电检测之前将相位调制转换成强度调制, 电谱方法的主要困难在于需要对探测器的不平坦响应进行额外校准. 提出了利用双音外差实现电光相位调制器半波电压自校准测量新方法, 该方法利用双音电光相位调制的边带与移频光载波的外差拍频, 对外差拍频信号进行频谱分析, 获得电光相位调制器的半波电压; 通过设定双音调制信号的频率关系, 克服了探测器光电转换中的不平坦频率响应, 实现了自校准测量. 该方法可扩展探测器和频谱仪的测试频率两倍以上, 节省至少一半的带宽需求. 与光谱测量方法相比, 该方法测试分辨率大幅提高且避免了光源线宽的影响; 与传统电域测量方法相比, 该方法无须额外校准, 无驱动功率和工作波长限制, 且对测试仪器带宽需求降低一半以上. 实验证实了所提方法获得的电光相位调制器半波电压的测量结果与光谱分析法获得的结果一致, 且大幅度地提高了测量范围和分辨率. 该方法提供了非常简单的电光相位调制器微波特性化分析方法, 对其他光电子器件分析也提供了参考.     

Novel low‐loss waveguide delay lines using Vernier ring resonators for on‐chip multi‐λ microwave photonic signal processors

In this paper, novel photonic delay lines (DLs) using Vernier/non‐identical ring resonators (VRRs) are proposed and demonstrated, which are capable of simultaneous generation of multiple different delays at different wavelengths (frequencies). The simple device architectures and full reconfigurability allow the DLs to be integrated with other functional building blocks in photonic integrated circuits to realize on‐chip, complex multi‐λ microwave photonic signal processors with reduced system complexity. To prove the concept, DLs using VRRs in cascaded and coupled configurations have been fabricated in TriPleX^TM waveguide technology, which enables a very low delay‐induced loss of approximately 0.18 dB/100 ps. The fabricated DLs demonstrated simultaneous generation of four incremental delays, where a maximum incremental step of 550 ps and a corresponding top delay of 1650 ps were measured for a bandwidth up to 1 GHz. To our knowledge, this is the first report on VRRs for delay generation functionalities.     

In situ characterization of optoelectronic nanostructures and nanodevices

One-dimensional (1-D) semiconductor nanostructures can effectively transport electrons and photons, and are considered to be promising building blocks for future optoelectronic nanodevices. In this review, we present our recent efforts to integrate optical techniques and in situ electron microscopy for comprehensively characterizing individual 1-D optoelectronic nanostructures and nanodevices. The technical strategies and their applications in “green” emission and optical confinement in 1-D ZnO nanostructures will be introduced. We also show in situ assembly and characterization of nanostructures for optoelectronic device purposes. Using these examples, we demonstrate that the combination of optical techniques and in situ electron microscopy can be powerful for the studies of optoelectronic nanomaterials and nanodevices.     

高性能注入锁相光电振荡器

提出一种基于注入锁定和锁相环技术的注入锁相光电振荡器.利用注入锁定来改善光电振荡器的近载频相噪以及杂散抑制度.将光电振荡器的输出信号与外注入源进行鉴相,通过锁相环来提升频率稳定性,并进一步改善光电振荡器的近载频相噪.实验结果表明:注入锁相光电振荡器在电滤波器中心频率为9.5GHz、3dB带宽为20 MHz和光纤环长度为6km的情况下,实现了输出信号频率为9.5GHz的单模振荡;当注入锁定带宽为1.98kHz时,光电振荡器输出信号在1kHz频偏处的相位噪声为-125dBc/Hz,在10kHz频偏处的相位噪声为-147dBc/Hz,杂散抑制度高于80dB,阿伦偏差接近1.37×10~(-11)@1s和1.22×10~(-11)@1000s.     

Ka/Q band GaAs IMPATT amplifier technology

GaAs IMPATT diodes are capable of generating 2 to 3 W simultaneously with 18–22% efficiency in the 33 GHz to 46 GHz frequency band. The design of the amplifier circuits which utilize these devices is discussed. The circuit design is based on a 3-step closed form algorithm. The first step is a passive circuit characterization with an automatic network analyzer. In the second step, a computer is used to generate diode device lines. The third step is load line synthesis for predictable operation. The resulting performance is described. 2 W over a 2GHz bandwidth was achieved simultaneously with a minimum gain of 12 dB.     

Optoelectronic oscillator using a LiNbO3 phase modulator for self-oscillating frequency comb generation

Optical frequency comb generation by using a novel optoelectronic oscillator (OEO) is proposed and demonstrated with the emphasis placed on self-oscillating operation. In the OEO, a wideband LiNbO3 phase modulator is driven with a large-amplitude radio-frequency (RF) feedback signal to generate a deeply phase-modulated light wave; accordingly, an optical frequency comb with a bandwidth greater than the RF signal is generated by self-oscillation. Although it generates multifrequency components, the OEO exhibits characteristics of a single-mode oscillator. Its operation is stable and self-starting. An optical frequency comb with a 120 GHz bandwidth and 9.95 GHz frequency spacing was successfully generated by self-oscillation at a single frequency.     

In situ characterization of optoelectronic nanostructures and nanodevices

One-dimensional (1-D) semiconductor nanostructures can effectively transport electrons and photons, and are considered to be promising building blocks for future optoelectronic nanodevices. In this review, we present our recent efforts to integrate optical techniques and in situ electron microscopy for comprehensively characterizing individual 1-D optoelectronic nanostructures and nanodevices. The technical strategies and their applications in “green” emission and optical confinement in 1-D ZnO nanostructures will be introduced. We also show in situ assembly and characterization of nanostructures for optoelectronic device purposes. Using these examples, we demonstrate that the combination of optical techniques and in situ electron microscopy can be powerful for the studies of optoelectronic nanomaterials and nanodevices.     

Injection-locked fiber laser for tunable millimeter-wave generation

A dual-ring injection-locked fiber laser consisting of a ring of optoelectronic oscillator (OEO) and a ring of fiber laser is proposed and demonstrated for tunable millimeter-wave (mm-wave) generation. The approach combines the advantages of mm-wave generation based on OEOs and fiber lasers, which can generate a high-frequency, low-phase-noise, and a mode-hopping-free mm-wave signal with a large tuning range. A low-phase-noise mm-wave signal with a tunable frequency of 30-50 GHz and a tuning step of 10 GHz is obtained in a proof-of-concept experiment. The tuning range can be as large as 140 GHz if a high bandwidth photodetector is applied.     

<Emphasis Type="Italic">In situ</Emphasis> characterization of optoelectronic nanostructures and nanodevices

One-dimensional (1-D) semiconductor nanostructures can effectively transport electrons and photons, and are considered to be promising building blocks for future optoelectronic nanodevices. In this review, we present our recent efforts to integrate optical techniques and in situ electron microscopy for comprehensively characterizing individual 1-D optoelectronic nanostructures and nanodevices. The technical strategies and their applications in “green” emission and optical confinement in 1-D ZnO nanostructures will be introduced. We also show in situ assembly and characterization of nanostructures for optoelectronic device purposes. Using these examples, we demonstrate that the combination of optical techniques and in situ electron microscopy can be powerful for the studies of optoelectronic nanomaterials and nanodevices.     

1.5 μm Ti:LiNbO3电光波导强度调制器

用钛内扩散技术和常规光刻手段,研制出1.5μmLiN_bO₃电光波导强度调制器。它由单模波导非对称Mach-Zehnder干涉仪和三电极共平面波导组成。干涉仪的两个臂长相差波导波长的四分之一,使器件在最佳线性点工作,无需外加电偏压。集总调制和行波调制的理论带宽分别为1GHz和7.8GHz。对于集总器件,测量了调制特性,半波电压为9.5V,调制带宽为0.7GHz。     

应用于ROF系统中的单边带调制微波毫米波生成技术研究

介绍了单边带调制微波毫米波生成技术研究的背景及意义,综述了几种主要的单边带调制微波毫米波生成技术方案,包括移相法、滤波法、非线性效应法,以及在此基础上的改进方法,如应用于ROF系统中基于谐波抑制的新型单边带调制方案、应用超窄双传输峰光纤光栅实现光学单边带调制等。还介绍了两种新型单边带调制生成微波毫米波技术,包括基于极性反转电光调制器的单边带调制技术以及新型光学注入锁定单边带调制实验系统     

基于外调制器的全双工无线信号光传输系统

提出了一种基于双平行马赫 增德尔调制器的全双工矢量信号传输系统。传统的光学倍频技术只适用于NRZ (not return to zero) 等强度调制格式,而不适用于无线通信中常用的MPSK、MQAM等矢量信号调制技术,用传统的倍频技术生成光毫米波后,用滤波器将其2个边带分开,在其中一个边带上调制矢量信号,这样幅度和相位信息被正确保留,且使用了8倍频模块,降低了传输过程中对光电器件的带宽要求。理论分析和仿真结果表明:通过此方法产生的携带在60 GHz载波上的625 Msymbol/s的4QPSK信号,经过20 km单模光纤传输后,误差向量幅度损耗可以忽略不计。     

Monolithically-integrated optoelectronic circuit for ultrafast sampling of a dual-gate field-effect transistor

An integrated optoelectronic circuit for ultrafast sampling of multi-terminal devices is described. This is achieved using optimized photoconductive switches fabricated from low-temperature-grown GaAs, monolithic integration of the device with the sampling circuit, control of the electromagnetic modes propagating on the coplanar waveguide using microfabricated airbridges, and discrimination of guided and freely-propagating modes using a novel electrooptic sampling method. As an example, the scattering parameters associated with the propagation of a picosecond pulse through one of the gates of a dual-gate heterojunction field-effect transistor are obtained at frequencies up to 300 GHz. The inter-gate capacitance is determined by measuring the electromagnetic transient coupled between the gates.     

熔锥型宽带耦合器的研制

介绍了全光纤熔融拉锥型3dB宽带耦合器的理论设计，根据理论设计制作了样品。应用耦合模理论分析了全光纤非对称熔融拉锥型耦合器的宽带特性；提出了3dB宽带耦合器的制作方案，在此基础上制作了样品；对样品进行测试，样品带宽大约为300nm(在1300nm～1600nm波长之间)，附加损耗小于0.5dB，完全达到了实用化的要求。     

海水盐度光纤遥测技术研究——测量原理

提出了一种用于海水盐度检测的光学新方法 ,利用光纤光学技术与CCD检测相结合的测量技术 ,并通过测量待测海水与参考蒸馏水的折射率差的方法 ,减小了盐度测量受温度的影响 ,并可实现海水盐度的自动化远距离遥测。建立了测量原理的理论模型。该系统水下的测量探头部分由无源的全光学结构组成 ,具有结构紧凑、精度高、抗电磁干扰、防燃、防爆、可柔性弯曲等诸多优点 ,在海洋勘探 ,环境监测以及军事、进出口贸易中的水尺计重等领域有广泛的应用前景和实用价值     

A large bandwidth photonic delay line using passive cascaded silicon-on-insulator microring resonators

This paper investigated the design and the characterization of a photonic delay line based on passive cascaded silicon-on-insulator (SOI) microrings.We considered the compromise of group delay,bandwidth and insertion loss.A 3-stage double channel side-coupled integrated spaced sequence of resonator (SCISSOR) device was optimized by shifting the resonance of each microring and fabricated with electron beam lithography and dry etching.The group delay was measured to be 17 ps for non-return-to-zero signals at different bit rates and the bandwidth of 78 GHz was achieved.The experiment result agreed well with our simulation.     

Wide-band nulling system for antenna array based on a photonic microwave filter and optical delay lines

A nulling system for phased array antennas with broad bandwidth and reduced complexity is presented. The system is based on combining the output of an optical beamforming network with an optical transversal filter steered in the angle where a null is desired in a configuration that reduces the number of optoelectronic conversion compared to previous proposals. Preliminary experimental results to show the feasibility of the concept are provided between 2 and 6 GHz, showing null depths of 22, 10 and 19 dB at 2, 5 and 6 GHz, respectively.     

Design trade-offs in optoelectronic parallel processing systems using smart-SLMs

Optoelectronic devices with free-space optical interconnections offer new possibilities in massively parallel processing. The trade-offs involved in system design and device selection for optoelectronic implementations are examined. System design trade-offs are approached from algorithmic and technological standpoints. From the algorithmic standpoint, new architectures based on expander graphs, that have been shown to provide low-contention fault-tolerant communication, are discussed. Optoelectronic systems which implement such random graphs can be folded to reduce the hardware cost or unfolded to increase bandwidth. They can also be partially folded by increasing the grain size or by reducing the randomness of the graph topology to reduce the complexity of the interconnection holograms. An optoelectronic and a VLSI implementation of a multistage interconnection network are compared from a technological standpoint. Physical design parameters, such as the chip size or the number of phase levels of the interconnection holograms, are related to the system design metrics such as bandwidth, volume, area and power. It is shown that the optoelectronic implementations have higher performance and are more cost-effective than VLSI implementations. These results are also used to provide general guidelines for device selection in the design of smart pixels/smart spatial light modulators based optoelectronic systems.