四端口光纤声光器件的耦合模理论

简述了光纤的声致折变机制,在复合光波导理论基础上讨论了光纤零耦合器与常规光纤耦合器的本质区别,指出零耦合器实质上是一段可以选择激励的双模光纤。从耦合模理论出发,求解了零耦合器中声致模耦合渐进方程组,给出了四端口光纤声光器件功率耦合的完整解析表达式,阐明了器件输出光的频移特性,解释了器件在声光谐振时具有的倍频声光调制、可调光移频、光滤波、光分束、光开关等功能。最后报道了器件作为可调光分束器或光开关的研究实例。     

国家海洋局海洋技术研究所系列声光器件简介

国家海洋局海洋技术研究所声光技术实验室,是国内开展声光技术研究与开发较早的单位之一,自1974年至今,已有十五年历史。该实验室在首先导出了不同状态下声光衍射的完整数学解之外,独创了一套声光器件的加工工艺,可成功地制做1GHz以内的各种声光器件;能对声光器件的20多个声、光、电学参数定量测量。研制的各种声光器件已在国内20多所大专院校和科研单位应用。     

超声跟踪反常氯化亚汞声光器件的设计及性能分析

氯化亚汞（Ｈｇ２Ｃｌ２）单晶具有独特的声光特性，这使得Ｈｇ２Ｃｌ２声光器件－Ｂｒａｇｇ盒适用于各种光信号处理。本文以超声跟踪反常器件的设计思想为基础，得出了Ｈｇ２Ｃｌ２器件的设计参数，并分析了这类新型器件的性能。结果表明，该器件有良好的性能，特别是其体积比同类ＴｅＯ２器件小得多。这些优点使之可望成为二维声光信号处理系统的关键器件。     

多维正常声电光效应最佳工作模式的确定

通过对四方、立方晶系的纵向电光效应和多维正常声光效应的研究，选定了四方晶系的KDP晶体和立方晶系的GaP晶体作为多维正常声电光器件的最佳晶体，并通过计算两种晶体的声光互作用性能参量，确定了它们的二维、三维、四维正常声电光效应的最佳工作模式。研究结果为多维正常声电光器件的设计与制作打下了良好基础。多维声电光器件在多路光通信和多通道光信息处理中有应用前景。     

超高速光纤耦合声光调制器的设计及其应用

为实现小于10 ns光脉冲上升时间的超高速声光调制,该文提出一种光纤耦合声光调制器光脉冲时域响应的理论设计仿真方法。利用该方法对1064 nm和1550 nm工作波长光纤耦合声光调制器进行了仿真,结果预测器件的光脉冲上升时间分别为9.4 ns和9.1 ns;通过器件制作和测试验证,两个波长的器件实测光脉冲上升时间分别为9.74 ns和9.22 ns,实测与理论仿真结果偏差较小。文章最后对器件在超快光纤激光器种子源光脉冲选单、光纤水听阵列时分复用及潜在的宽带移频应用进行了介绍。     

光声光谱气体传感技术研究进展

光声光谱是通过光声效应把样品吸收光谱转换成声波探测,实现样品成分、浓度分析检测的一种光谱传感技术,是光谱学的一个重要分支。光声光谱除了具有吸收光谱的高选择性、高灵敏度外,还具有信号只跟样品光吸收有关,不受散射光影响,零背景, 信号与光功率成正比以及信号探测器不受光波长影响等诸多优点。在环境监测、工业过程控制与检测、医学诊断和国防危化品检测等领域得到了越来越多的应用,呈现出快速发展的趋势。除了传统的共振光声光谱技术,近年来先后出现了悬臂增强型光声光谱、石英音叉谐振增强型光声光谱、多通道光声光谱等各具特色的新技术。对光声光谱气体传感技术的研究进展进行了介绍,并分析了其应用前景和未来发展趋势。     

用He-Ne激光声光器件进行声光幅度调制和声光偏转实验

描述了用He－Ne激光声的声光器件进行的声光调制和声光偏转实验。调制曲线上有一个拐点，在拐点附近的一段曲线可看成直线，利用这段曲线进行调制可减少失真。     

声光子晶体微腔的光声传感特性

声光子晶体是一种同时具有光子和声子带隙的人工微结构,因此可实现对光和声的同时操控,在腔光力学及声光功能器件领域展现了广阔的应用前景。本文基于有限元数值计算方法,研究了声光子晶体微腔的光声传感特性。研究结果表明,通过简单地引入点缺陷,声光子晶体不仅能很好地实现对光和声场的同时局域,而且能同时获得光及声信号的高灵敏度传感,光、声传感灵敏度分别达到了277nm/RIU,2.75MHz/ms-1。由于光和声两个物理量能同时并独立地实现高灵敏度传感,因此该种传感器能应用于更为复杂的生化传感。     

教学用声光实验装置和激光针灸机研制成功

一、教学用声光实验装置正式投产 由国家海洋局海洋技术研究所研制的教学用YZY3-1 型声光调制器已有偿转让给辽宁阜新市测试仪器厂.1985年6月30日,在厂家召开了市级产品定型鉴定会,现已正式投产.该产品包括三部分:固体声光器件、可供研究液体介质的声光波及电驱动部分.与目前大学实验室通用仪器配套,可完成包括光通讯、声速测量等20个现代声光学实验、该产品并备有《声光原理及其实验》一书,该书共约15万字. 二、利用声光调制器的调制型激光针灸机     

适用于硅微谐振器件测量的光纤位移传感器研究

对一种适用于硅微机械谐振器件测量的光纤位移传感器进行了研究,该光纤位移传感器探头采用了单根光纤探测形式和光纤“X”耦合器结构,在微弱光电传感信号处理上采用了“锁相放大器”提取方案,可以实现对静态位移和振动位移两种场合进行测量.对该传感器的实测结果表明:该传感器测量范围为0～100 μm,测量灵敏度3.95 mV/μm,精度等级优于1%,重复性优于0.5%.为作为应用实例,运用该传感系统对一种微悬臂梁硅微谐振器件进行了测量,成功提取了硅微谐振器件的微弱谐振信号,证实了该传感器可以实现对硅微谐振器件的非接触和无损测量,并具有非接触、易调试、高灵敏度等优点.     

Broad-band band-pass filter with variable center frequency and band width

This paper describes a new type of broad-band band-pass filter in which both the center frequency and band width are variable. The filter is composed of four balanced mixers, two local oscillators, an amplifier, and high-pass and low-pass filters. The center frequency and band width can be varied by changing the frequencies of two local oscillators. The center frequency is variable in the range 2–16 GHz, and the band width in the range 20–800 MHz.     

A numerical analysis on the homogenous property for integrated narrow band pass filter

The integrated narrow band pass filter is an important photonic device. The performance of this device is limited by the two problems, absorption coefficient and thickness homogeneous in the resonant cavity layer. We have developed a numerical simulation method to analyze the factors’ influence on the behavior of integrated filters. It is found that the non-homogeneous of layer thickness will play a dominance role in the property of band width of transmission spectra of the 32-chanels integrated narrow band pass filter device in near infrared.     

Bandwidth tunable high-Tc superconducting filter

We have developed a high-T_c superconducting band-pass filter, whose center frequency and bandwidth can be tuned independently, with steep attenuation at both lower and higher band edges. This tunable filter is composed of two different types of band-pass filters, one with steep attenuation at the lower band edge and the other with steep attenuation at the higher band edge. Two filters are connected in series and each filter is covered with additional dielectric plates, respectively. The tuning characteristics of the entire filter can be controlled by adjusting the distances between the dielectric plates and the substrate. The entire filter was fabricated monolithically on a 30-mm-wide and 60-mm-long LaAlO₃ substrate. A center frequency of 1.93 GHz, a 3 dB bandwidth of 20 MHz, and an attenuation of 30 dB, 1.0 MHz apart from both band edges, were obtained for the entire filter. Then, a sapphire plate was set above each of two filters, and a center frequency tuning of 10 MHz and a bandwidth tuning of 5 MHz were obtained by adjusting the distances between the substrate and the sapphire plates.     

密集波分复用薄膜滤光片的群延迟补偿设计

设计了一种基于薄膜干涉理论的反射式相位补偿器件，用以补偿密集型波分复用窄带滤光片所产生的群延迟，使50GHz薄膜滤光片的群延迟特性适应于40Gb／s系统的要求，在0．2nm带宽下群延迟波动从10ps左右下降到0．76ps以下。     

S波段窄带带通体声波滤波器设计

针对无人机测控应用设计了一种S波段窄带带通体声波(BAW)滤波器,其技术指标为:中心频率2.46 GHz,带宽41 MHz,带内插损大于-3 dB,带内纹波小于1 dB,带外抑制小于-40 dB@2.385 GHz和2.506 GHz。采用Mason模型设计了BAW滤波器中各薄膜体声波谐振器(FBAR)的叠层结构;使用变迹法设计了各FBAR(电极)的形状;采用一种自行开发的自动布局方法得到紧凑的BAW滤波器布局;建立了BAW滤波器的声-电磁协同仿真模型,通过这种高保真的多物理场仿真方法对设计结果进行了性能验证。该设计流程是通用的,并且有两个特点:采用声-电磁协同仿真方法对设计阶段的BAW滤波器进行最终性能检验,可以及早发现并拒绝1D Mason模型过于乐观的设计;滤波器布局设计中采用了一种新的自动化布局方法,大大简化了在此阶段的反复尝试工作,也为声-电磁协同仿真模型输出了必需的面内结构信息。     

Passive and temporally continuous optical spectral analyzer of RF signals via wavelength coding

A novel approach realizing an optical spectrum analyzer for photonic detection of an unknown RF carrier signals is presented. The described module may be part of an electronic warfare system in which detection of a narrow band RF signal is required. Moreover, The RF signal is characterized by an unknown time varying carrier frequency embedded in wide band noise. The system uses a passive, fiber based photonic configuration. It allows the spectrum mapping of an incoming electronic RF signal modulated on an optical carrier. The spectral analyzer configuration uses a finite impulse response (FIR) filter that is realized by two different optical paths of parallel fibers which generate a spectral notch filter. Hence, a wavelength coding is realized by chromatic dispersion such that each wavelength is filtered by a different FIR filter. Therefore, the energy at a WDM demux output channels is actually proportional to the spectrum of the input RF signal. This spectral mapping is obtained without lose of temporal RF information.     

基于TM010模介质谐振腔的小型化腔体滤波器

现用于4G基站的介质腔体滤波器都采用TE_01δ模介质谐振腔,虽然其品质因数Q值很高,但体积较大。为了小型化介质腔体滤波器,创新性地使用了TM₀₁₀模介质谐振腔,虽然其Q值比较低,但同样能满足高带外抑制的要求。对TM₀₁₀模介质谐振腔的端口耦合和两腔之间的磁耦合、电耦合进行分析研究,创新性地使用了介质窗的形式产生电耦合,避免了使用飞杆,易于加工,降低制造成本。最后设计了一个8腔TM₀₁₀模准椭圆函数介质腔体带通滤波器,在通带(TD-LTE频带,2570~2620 MHz)两端分别设计两个传输零点以提高带外抑制。调试结果表明,TM₀₁₀模介质腔体滤波器不仅能满足低插损、高带外抑制的要求,而且其体积大幅度缩小。     

薄膜截止滤光片的消偏振设计

薄膜截止滤光片在倾斜入射时不可避免地会产生s和p二个偏振分量的分离,因而在许多应用,特别是光通讯的应用中成为一个棘手的难题。提出了一种新的设计方法,对最常用的45°入射角,实现了长波通和短波通两种截止滤光片的完全消偏振, 在透射率为50%处,其偏振分离分别为0.3 nm和0.1 nm。基本的设计方法是采用宽带法布里珀罗薄膜干涉滤光片中心波长两侧的干涉带作为长波通或短波通截止滤光片的初始膜系,然后经过适当的优化以提高透射带的透射率。宽带干涉滤光片的间隔层常由半波长厚度的高、低折射率混合膜层组成,如2H2L2H或2L2H2L。由于这种设计的截止区和透射带带宽常嫌不足,故提出了展宽截止区和透射带的方法。对一个典型的短波通截止滤光片,在波长1550 nm,截止区和透射带宽均达到了200 nm。这种设计方法不仅简单、性能优良,而且膜厚控制容差较大,故易于制造。     

Wi-Fi频段体声波滤波器的设计

为了保证移动设备在Wi-Fi频段正常工作且不受相邻频段的干扰,设计了一种用于Wi-Fi IEEE802.11b频段(2402~2482 MHz)的BAW滤波器。设计基于薄膜体声波谐振器(FBAR)的一维Mason等效电路模型构成初始结构的梯形滤波器。然后,将串联FBAR的谐振区面积值以及串、并联FBAR的谐振区面积的比值设置为优化参数,以所需的滤波器的带内插损和带外抑制为优化目标,使用ADS软件基于遗传和梯度的优化算法对滤波器进行优化。在滤波器的设计过程中,为了使仿真结果更加精确,采用声电磁协同仿真方法对滤波器进行仿真,并与Mason 等效电路模型仿真结果对比,结果表明,滤波器性能有所下降,带内插损增大1.6 dB,带内纹波增大1.1 dB,带外抑制基本一致。所设计的Wi-Fi频段的BAW滤波器具有低插入损耗(小于3 dB)、高带外抑制(大于40 dB)性能。     

Photonic crystal narrow filters with two neighboring waveguides and a semiconducting point defect

A tunable filter is demonstrated based on a squared lattice two-dimensional photonic crystal. The filter is formed by a single semiconducting point defect and two neighboring waveguides. Modal properties of the defect modes and the transmittance of the proposed system are analyzed using supercell method and finite difference time domain method, respectively. We show that there is a narrow pass band for each temperature between 218 and 240 Kelvin. The peak of the pass band transmittance and the frequency can be highly tunable with the temperature of an intrinsic semiconducting point defect. Also, we have showed that the frequency and temperature of the desired high transmitted filter do not sensitive on the cavity size.