Asymmetrical Fabry-Perot cavity slot micro-ring resonator and its sensing characteristics

To achieve high quality factor and high-sensitivity refractive index sensor,a slot micro-ring resonator(MRR)based on asymmetric Fabry-Perot(FP)cavity was proposed.The structure consisted of a pair of elliptical holes to form an FP cavity and a microring resonator.The two different optical modes generated by the micro-ring resonator were destructively interfered to form a Fano line shape,which improved the system sensitivity while obtaining a higher quality factor and extinction ratio.The transmission principle of the structure was analyzed by the transfer matrix method.The transmission spectrum and mode field distribution of the proposed structure were simulated by the finite difference time domain(FDTD)method,and the key structural parameters affecting the Fano line shape in the device were optimized.The simulation results show that the quality factor of the device reached 22037.1,and the extinction ratio was 23.9 dB.By analyzing the refractive index sensing characteristics,the sensitivity of the structure was 354 nm·RIU−1,and the detection limit of the sensitivity was 2×10−4 RIU.Thus,the proposed compact asymmetric FP cavity slot micro-ring resonator has obvious advantages in sensing applications owing to its excellent performance.

Surface Plasmon Interference Lithography Assisted by a Fabry-Perot Cavity Composed of Subwavelength Metal Grating and Thin Metal Film

A surface plasmon interference lithography assisted by a Fabry-Perot （F-P） cavity composed of subwavelength metal gratings and a thin metal fihn is proposed to fabricate high-quality nanopatterns. The calculated results indicate that uniform straight interference fringes with high contrast and high electric-field intensity are formed in the resist under the F-P cavity. The analyses of spatial frequency spectra illuminate the physical mechanism of the formation for the interference fringes. The influence of the F-P cavity spacing is discussed in detail. Moreover, the error analyses reveal that all parameters except the metal grating period in this scheme can bear large tolerances for the device fabrication.

基于FP腔实现光纤与边缘耦合器高效对准

【目的】通过集成在片上的硅基边缘光耦合器(以下简称边缘耦合器),硅光子芯片可以与光纤实现低损耗耦合。在商用硅光子芯片的封装流程中,大规模的光纤与硅光子芯片对准需求对光纤与边缘耦合器的对准效率提出了更高的要求。文章的研究目的是基于光纤端面与边缘耦合器端面之间形成的法布里-珀罗(FP)腔对光纤与边缘耦合器的对准流程进行优化。在光纤轴向(文章中表示为x轴方向)这一自由度上对光纤与边缘耦合器之间的距离进行测量后,将光纤沿该方向进行单次调节即可完成与边缘耦合器的高精度对准。【方法】文章研究了光纤端面与边缘耦合器端面之间形成的FP腔结构,建立了FP腔的反射/透射光谱与端面间距之间的物理模型。搭建光纤对准平台完成了基于FP腔测量端面之间距离的实验,然后基于FP腔测距结果,将光纤沿光纤轴向进行单次位置调整来实现与边缘耦合器的对准。【结果】实验中得到的FP腔长值与仿真得到的理想FP腔模型腔长值的偏差小于1μm,测得的光纤位移距离在实际位移的误差范围(±1μm)内。基于测距结果调整光纤位置后,在输出端口光纤与边缘耦合器之间的光耦合损耗为3.52 dB,与参考值(3.30 dB)的误差仅为0.22 dB。【结论】文章验证了基于FP腔实现光纤与边缘耦合器高效对准的可行性。通过FP腔实现了对光纤与边缘耦合器间距以及光纤位移的测量,测量精度为亚微米级。文章还通过实验验证了基于FP腔的测距结果,仅需对光纤进行单次位置调整即可实现与边缘耦合器的高精度对准。

An Ultraviolet Fiber Fabry-Perot Cavity for Florescence Collection of Trapped Ions

We demonstrate a fiber Fabry-Pérot cavity in the ultraviolet range, which covers the florescence wavelength for the 2P to 2S transition of Yb and is designed in the bad cavity limit for florescence collection. Benefiting from both the small cavity mode volume and the large atom dipole, a cavity with moderate finesse and high transmission still supports a good cooperativity, which is made and tested in experiment. Based on the measured experimental parameters, simulation performed on the cavity and ion shows a Purcell factor better than 2.5 and a single-mode fiber collection efficiency over 10%. This technology can support ultra-bright single photon sources based on trapped ions and can provide the possibility to link remote atoms as a quantum network.

基于双金属和FP干涉结构的光纤温度传感器

为了提高现有光纤温度传感器的灵敏度和测温范围,提出了一种基于双金属和法布里—珀罗(FP)干涉结构的传光型光纤温度传感器。以双金属片作为感温元件,利用部分反射镜和双金属片作为上、下表面,构成FP腔,采用调频激光干涉原理测量感温元件受热产生的FP腔腔长变化量,实现对温度的传感。实验结果表明:制成的光纤温度传感器的腔长变化量与温度呈较好的线性关系,线性度为99.96%,温度测量灵敏度达到了3885nm/℃,重复性高。

Improved Directivity of an OAM Antenna by a Fabry-Perot Cavity: An Experimental Study

The circular phased antenna array is commonly used for generating waves bearing Orbital Angular Momentum (OAM) in the radio frequency band, but it achieves a relatively low directivity. To overcome this drawback, we present here a method to improve the directivity of an OAM circular phased antenna array by embedding it inside a Fabry-Perot cavity. The Fabry-Perot cavity contains three main parts: a partially reflecting surface (PRS), an air cavity and a ground plane. Simulation data show that the directivity of this new OAM antenna achieves an improvement of 8.2 dB over the original array. A prototype is realized and characterized. The simulated and measured characteristics are in good agreement.

Effective transmittance of Fabry–Perot cavity under non-parallel beam incidence

The Fabry–Perot(FP) resonant cavity is widely used in laser and spectroscopic measurements due to its unique interference transfer function(ITF). In the ideal case of parallel incident light, the ITF of the FP resonant cavity can be expressed by the Airy function. However, in reality, it is difficult to achieve perfect parallelism with collimated beams. In this article, a theoretical model is established for non-parallel light incidence, which assumes that the non-parallel incident light is a cone-shaped beam, and the cone angle is used to quantify the non-parallelism of the beam. The transmittance function of the FP resonant cavity under non-parallel light incidence is derived. The accuracy of the model is experimentally verified. Based on this model, the effects of divergence angle, tilt angle and FP cavity parameters(reflectivity, cavity length)on the ITF are studied. The reasons for the decrease in peak value, broadening and asymmetry of the interference peak under non-parallel light incidence are explained. It is suggested that a fine balance between the interference peak and the collimation effect of the incident light should be considered in the design and application of FP resonant cavities, especially for tilted applications such as angle-scanned spectroscopy. The research results of this article have certain significance for the design and application of FP resonant cavities.

微机械FP腔可调谐滤波器在WDM系统中的串扰分析

介绍了一种以FP谐振腔为基础 ,用于波分复用系统的MOEMS器件—电控可调谐FP光滤波器 器件采用微电子机械加工技术研制 研究了FP型解复用器在密集波分复用系统中引入的信道间串扰对系统的影响 ,并分别讨论了激光器线宽、滤波器带宽、信道间距对串扰的影响 在信道间隔为 10 0GHz ,激光器线宽为 5GHz ,串扰可达到 - 2

以EDFA为光源的光纤Fabry-Perot腔位移传感

提出了一种新颖的光纤位移传感测量方法,采用空芯石英光纤内置单模光纤的方法制作了腔长可随待测目标移动而变化的非本征型光纤法布里-珀罗(FP)腔,利用EDFA光源的宽带光照射FP腔,其形成的多光束干涉谱通过多峰检测法,反算光纤FP腔的绝对腔长,实现对微小位移量的精确测量。根据所设计的方案,搭建了相应的光纤FP腔位移传感系统,实现了11 mm长度范围内1μm位移分辨率、40.4 dB动态范围的位移传感。

基于可调FP腔的光脉冲时域混叠编解码技术研究

针对海底光缆通信系统面临的光信息的传输安全问题,提出了采用腔长可调的FP谐振腔,对传输速率为10Gb/s的皮秒光脉冲信息进行时域混叠编解码,实现了100km的光信息安全传输实验。

基于FPGA的可调谐光纤激光器频率锁定控制电路

根据PDH(Pound-Drever-Hall)稳频技术原理设计了基于FPGA的可调谐光纤激光器频率锁定控制电路,利用Matlab/Simulink建立频率误差信号解调电路模型,仿真结果表明能够输出频率误差信号。以FPGA为核心控制A/D采集光电探测器探测的信号,结合DDS(Direct Digital Synthesizer)技术在FPGA内部实现混频和低通滤波的功能,实验结果与仿真结果相符,能够解调出光纤激光器输出激光的频率锁定误差信号。根据此误差信号调节反馈电压,改变受压电陶瓷调谐的有源相移光纤光栅峰值谐振波长,实现对激光器的频率锁定,为光纤激光器稳频系统的集成化奠定了基础。

FP腔腔长的测量新方法

ＦＰ腔是ＷＤＭ光纤通信系统中用于波长控制和解调的关键器件。为了进行匹配系统的设计以及计算已制成腔的自由谱区，准确测定腔长是必不可少的工作，但是由于ＦＰ腔的具体结构，测定腔长无法用直接的方法进行。本文通过谐振腔的谐振特性分析，推导出一种测量腔长的新方案。

FBG FP腔对连续波与脉冲激光入射的响应

在忽略FBG(光纤Bragg光栅)非线性效应的情况下,研究了单模光纤非线性效应对FBG FP(法布里-珀罗)腔输出特性的影响,导出了连续波及脉冲激光入射时,FBG FP腔透射率的数学表达式。研究结果表明,连续波入射时,FBG FP腔呈现双稳态输出特性;脉冲激光入射时,FBG FP腔的输出呈现衰荡特性,且出现调制不稳定性。

基于FP腔的大量程超声解调系统研究

针对光纤布拉格光栅(FBG)超声探测传感器测量灵敏度和量程相互制约的问题,文章提出了一种基于法布里珀罗(FP)腔和π相移FBG(π-FBG)的解调方案。文章分析了利用FP腔解调的原理并进行了详细的数值仿真分析。理论分析表明,利用FP腔的两个纵模作为一组解调器同时解调,可将系统灵敏度提高两倍,并且具有很好的线性度。扩展到多个纵模时可构建解调器阵列,从而极大地提高了系统的量程,有效地解决了测量灵敏度和量程相互制约的问题。数值仿真结果表明,该方案在实际可操作参数范围内切实可行,并具有灵敏度高和响应速度快等优势。

Low insertion loss silicon-based spatial light modulator with high reflective materials outside Fabry–Perot cavity

The extinction ratio and insertion loss of spatial light modulator are subject to the material problem, thus limiting its applications. One reflection-type silicon-based spatial light modulator with high reflective materials outside the Fabry-Perot cavity is demonstrated in this paper. The reflectivity values of the outside-cavity materials with different film layer numbers are simulated. The reflectivity values of 6-pair Ta2O5/SiO2 films at 1550 nm are experimentally verified to be as high as 99.9%. The surfaces of 6-pair Ta2O5/SiO2 films are smooth: their root-mean-square roughness values are as small as 0.53 nm. The insertion loss of the device at 1550 nm is only 1.2 dB. The high extinction ratio of the device at 1550 nm and 11 V is achieved to be 29.7 dB. The spatial light modulator has a high extinction ratio and low insertion loss for applications.

Investigations and prospects of Fabry-Perot antennas:a review

Fabry-Perot(FP)antennas have characteristics of planar structures combined with high gain,and they have been widely used in wireless communications.With the progress of ongoing research,FP antennas have achieved various capabilities,but many of them are still under development,such as lowprofile,wideband,circular polarization,multi-band,low-radar cross section(RCS)and reconfigurable features.This paper discusses the theoretical analysis methods and research progress of FP antennas,and explains the realization methods of different features of FP antennas.In order to indicate different technologies for realizing various capabilities,the key technologies and features of some of the latest designs are described.Finally,the research situation and prospects of FP antennas are summarized to guide their research directions in the future.

光纤铅酸蓄电池安全在线监测技术研究

铅酸蓄电池的电解液变化对于电池安全运行状态至关重要,研究植入性传感技术有助于精确监控蓄电池内部电解液变化等过程,及时在线获得蓄电池的实时工作性能与状态,在蓄电池安全监测领域具有重要意义。文章提出并设计了一种基于全光纤法布里-珀罗(Fabry-Perot,FP)干涉仪的液体浓度传感器,其探头是由两段单模光纤和一段U形毛细石英玻璃管构成的开放式FP腔,可以使液体轻松进入空腔,不易形成气泡。该结构具有耐强酸强碱、侵入性低、体积小、抗电磁干扰和绝缘体特性等优势,可植入铅酸蓄电池内部,实现对电解液中的硫酸溶液浓度的实时在线监测。结果表明:在硫酸为0~30%的体积分数范围内,FP腔的有效腔长和硫酸溶液的体积分数具有良好的线性度,其拟合系数达0.995,硫酸溶液的体积分数测量值与真实值之间的最大偏移量<±1.05%。

台面结构硅基法珀型光纤MEMS压力传感器的研究

提出了一种新的光纤压力传感器的设计,该传感器敏感膜采用了台面结构而非传统的平面结构.用法布里-珀罗(Fabry-Perot)干涉理论阐述了传感器的工作原理,提出了敏感膜的力学模型.基于Fabry-Perot干涉理论推导出光纤MEMS压力传感器中台面敏感膜受到的压力与干涉光强的关系表达式,通过ANSYS有限元软件分析了台面膜型的力学性能,结果表明台面敏感膜在平行度上优于平面膜.通过数值模拟分析了传感器的关键参数对其性能的影响,为光纤MEMS压力传感器的加工和制作提供了理论依据.

精确测量弱反射率、长腔长光纤光栅法布里珀罗腔中FBG中心波长的方法研究

提出了一种测量两个同波长的低反射率的光纤布拉格光栅(FBG)构成的光纤光栅法布里珀罗(FBG-FP)腔中两个FBG的中心波长的方法。FBG对温度敏感,一个FBG处于室温状态,改变另一个FBG的温度使其中心波长发生漂移,从而使两个FBG的中心波长分离开。通过拟合可以得到FBG中心波长随温度变化的线性关系,从而分别得到两个FBG在对应温度下的中心波长。研究结果表明,透射谱中心波长对温度的响应重复性好,测量结果稳定,使用该方法简单有效。

基于长波红外光谱的热态锻件温度场测量方法研究

提出一种长波红外光谱的温度场测量方法。将谱色测温原理与三级Fabry-Perot(FP)型Liquid Crystal Tunable Filter(LCTF)相结合,并对测温理论模型中三组非线性相关方程组所得的解进行了优化,以进一步减小误差,使测量值更加客观、真实;然后运用液晶双折射可调谐滤光原理,制作了三级FP型LCTF滤光系统,该系统在一定的长波红外光谱范围内实现了波长的任意调谐,从而保证测温系统的响应快速、准确。该方法测温前无需知晓被测物发射率,且能有效抑制背景光辐射和环境光源对测温精度带来的影响,保证了测温结果的准确性。最后通过matlab仿真软件验证了滤光系统所得红外光谱符合系统设计要求,并通过实验验证了该测温方法的可行性,测温准确性较之传统的单波段红外热像仪得到了提高。