反射式微光机电系统(MOEMS)的研究现状与展望

反射式微光机电系统是微光机电系统中的重要组成部分,近年来得到了较快的发展。介绍了反射式微光机电系统(MOEMS)的研究现状和最新进展。根据反射式微光机电系统的分类,列举了一些具有代表性的反射式MOEMS器件。简要介绍了反射式MOEMS的加工工艺;阐述了反射式MOEMS的应用领域;展望了发展前景。     

空间谐振式陀螺谐振腔的失调分析

为了克服平面谐振腔调节精度高、损耗大的困难,提出了一种新型空间谐振式陀螺的谐振腔结构。并利用光学变换矩阵和菲涅尔-基尔霍夫衍射积分公式建立数学模型,通过MATLAB仿真计算谐振腔各腔镜因失调引起的衍射损耗。计算结果表明当谐振腔边长为4cm,入射光束束腰半径为0.25mm时,凹面镜的曲率半径为0.397m,反射镜失调引起的衍射损耗近似为0,即失调对陀螺的性能没有影响。得到陀螺的极限灵敏度为1.54°/h。     

光子晶体光纤陀螺的谐振腔设计

提出了一种新颖的基于光子晶体光纤和空间光学元件的光学谐振腔结构,利用MATLAB软件进行了谐振腔谐振特性的计算与分析,并在此基础上完成了谐振腔设计.设计的分析结果表明,当谐振腔输入镜M1和输出镜M2的反射率等于0.99时,谐振清晰度可以达到43.5,谐振腔谐振深度可以达到0.9987,陀螺极限灵敏度可以达到0.5°/h.     

谐振腔光纤陀螺光纤谐振环特性研究

对有限光源线宽情况下反射式光纤谐振环的响应特性进行了研究,得到了光纤谐振环各谐振特性参量的表示式.分析了特性参量与光源线宽和耦合器特性的关系,结合对方波调制谐振腔光纤陀螺极限灵敏度的分析,给出了设计高灵敏度谐振腔光纤陀螺光纤谐振环的要求和原则.进行了谐振腔光纤陀螺用光纤谐振环的实验研究,制作了适用于谐振腔光纤陀螺的高精细度和高谐振深度光纤谐振环.     

无源谐振腔激光陀螺中的闭锁效应

从谐振腔的谐振特性出发，严格地推导出无源谐振腔激光陀螺中由腔镜背散射引起的闭锁效应关系式及闭锁阈值表达式。实验观察结果证实了理论推导的正确性。     

用于集成光学陀螺的波导谐振腔设计

给出了一种集成光学陀螺谐振腔的优化设计方案,在保证集成光学陀螺精度的同时更利于微型化。选用传输损耗为0.01dB/cm的硅基二氧化硅材料作基底,谐振腔内损耗仅为0.5dB,保证了谐振腔的高清晰度;采用准单模矩形波导结构,利用弯曲波导对一阶模的有效限制实现了光的基模传输,利于谐振腔的小型化;分析了波导的传输损耗、波导耦合器分光比对谐振腔性能及陀螺极限灵敏度的影响,得出波导耦合器分光比的优化参数,并仿真得到谐振腔的谐振清晰度达到70以上。在激光器线宽为30kHz,探测器响应度0.95A/W,积分时间为10s的条件下,系统的极限灵敏度为1.6°/h。     

谐振腔光纤陀螺相位调制复位误差影响的研究

对数字相位斜波调制中2π复位误差对谐振腔光纤陀螺（R-FOG）的影响进行了研究.结果表明,相位复位误差将会导致R-FOG输出光强信号的波动,光强波动周期等于相位斜波复位周期.反射输出光强的波动在相位斜波的前后半周期明显不同,前后半周期输出光强平均值的差异与复位误差的大小和方向相关.提出了一种相位调制复位误差的消除方法,利用前后半周期平均光强差作误差信号,反馈控制相位调制通道增益,可实现复位误差的消除.     

集成光学芯片的闭环光纤陀螺研究

简要分析集成光学芯片闭环光纤陀螺的构成、信号检测方法及电路实现方法。     

微型MOEMS阿达玛变换近红外光谱仪

提出一种运用微光机电系统(micro-opto-electro-mechanical systems,MOEMS)闪耀光栅,动态产生阿达玛变换模版的微型近红外光谱仪.它具有体积小、价格低、扫描速度快等突出优点.分析了这种新型近红外光谱仪的结构和工作原理,通过对MOEMS闪耀光栅编程,动态生成了 63阶阿达玛模版.实验得...     

面向谐振式微光学陀螺应用的球形谐振腔DQ乘积优化

基于谐振式光学陀螺高灵敏度、低成本与微型化的发展需求, 为了实现高灵敏度的谐振式微光机电陀螺, 提出了以集成光学微谐振腔领域里高Q值、大直径谐振腔的制作为目标, 应用方向为谐振式光学陀螺的球形光学微谐振腔核心敏感单元. 在实验中以氢火焰作为热源采用熔融法制备球形光学微谐振腔. 通过调节氢气的流量控制氢火焰热源面积, 制备了不同直径(300-2200 μm)的球形谐振腔, 分析了球形谐振腔Q 值、DQ乘积、陀螺灵敏度与谐振腔直径D的对应关系及其原因, 获得了最优参数的面向谐振式光学陀螺的球形谐振腔敏感单元. D=1260 μm时, 球腔品质因数 Q=7.18×10⁷, 得到的最优陀螺灵敏度约为10°/h, 满足商业级应用的需求, 为芯片级、高精度、低成本的新型谐振式光学微腔陀螺的研究奠定了实验基础.     

谐振型光纤陀螺方波频率调制方法

分析了谐振型光纤陀螺(R FOG)方波频率调制方法的工作原理和调制性能,得到了采用方波频率调制时R_FOG的极限灵敏度,并对方波频率调制和正弦频率调制两类调制方法的特性进行了比较。结果表明,方波调制方法的极限灵敏度优于正弦频率调制方法的极限灵敏度,其输出信号为方波强度调制信号,易于与I_FOG中类似的数字解调方法相结合,是实现全数字处理R_FOG的较理想的调制方案。     

微型光波导陀螺中无源环形谐振器研究

光波导无源环形谐振器是微型光波导陀螺的核心敏感部件，其性能直接影响陀螺的极限分辨率和各误差项，是此种陀螺设计和制造中的关键。本文通过理论分析，对无源环形谐振器进行了深入的研究，提出了可行的光学系统设计，并结合现有先进的光学工艺，提出了加工与制造的方案。     

平面环形谐振腔微光学陀螺结构设计与优化

提出具有高群有效折射率的双环级联作为核心元件的谐振式平面光波导陀螺结构, 基于光学Sagnac原理得到了双微环耦合谐振式光学陀螺理论灵敏度与群有效折射率的一般表达式和双环与单环陀螺系统的灵敏度关系, 并由耦合模理论方法得到了双环系统耦合器的两个透射系数对应的群有效折射率变化情况. 在环腔半径R₁=R₂=100 μm、环腔传输损耗系数t₁=t₂=0.95的情况下, 针对环与环之间耦合器和环与波导之间耦合器透射系数对群有效折射率的不同影响, 得到了最大群有效折射率的产生条件. 采用文中参数(R=100 μm, t=0.95)计算的单环谐振式陀螺灵敏度为(10⁴-10⁵)°/h, 而双环级联谐振系统理论灵敏度能够达到10 °/h. 该研究对微环耦合谐振腔在角速度检测上的应用有重要的意义.     

Research on time division multiplexing modulation approach applied in three-axis digital closed-loop fiber optic gyroscope

In this paper, the structure and the fundamental principle of a three-axis Time Division Multiplexing (TDM) fiber optic gyroscope system are presented. The design of TDM fiber-optic gyroscope system is mathematically analyzed. An effective modulation approach is developed, the bias stability compared with that of a normal fiber-optic gyroscope is theoretically given and the system dynamic character is presented. In order to test the correctness of the approach, the dynamic simplified model is introduced and the simulation is conducted. The experimental result matches the simulation, indicating that the TDM modulation approach is feasible.     

Study of reflection error in closed-loop polarization-maintained interferometric fiber optic gyroscope

To analyze quantitatively and systematically the reflection error in optical path of closed-loop polarization-maintained (PM) fiber optical gyroscope (FOG), the optical model is established and analyzed. Based on the optical model and the principle of the coherence detection in signal processing, the source of the reflection error is disclosed from the point of wave trains, and its effect on FOG performance is analyzed in detail, including variation as the step wave on modulator and as the environment temperature. In addition, the measures are promoted to suppress the reflection error, and the simulation result demonstrates that the peak-to-peak value of the reflection error can be suppressed from about 0.8°/h to less than 6×10⁻³°/h through matching the length of birefringent pigtails, which is small enough to meet the requirement of FOG with high performance.     

A MOEMS accelerometer based on photoelastic effect

In order to enhance the accuracy of three-component seismic acceleration detection, a novel three-component micro-optoelectronic mechanical systems (MOEMS) accelerometer based on photoelastic effect has been designed. The mechanical properties of sensitive unit under three-component acceleration are analyzed theoretically and a Finite Element Analysis (FEM) simulation is performed simultaneously. Meanwhile, a Mach-Zehnder (M-Z) interferometer which is based on photoelastic effect had been designed and a Beam Propagation Method (BPM) simulation has been processed as well, experimental results indicated that the sensor had a high sensitivity, wide frequency response range and a good linearity in the range of seismic band.     

Design of a pulsed spatial neutron magnetic spin resonator

It is well known that upon passage through a spatially alternating transverse magnetic field, produced by a meander-shaped conducting foil, in its rest frame each neutron creates its individual frequency which depends on its velocity and the period of the meander. A resonant spin flip process takes place, if this frequency equals the Larmor frequency determined by a homogeneous vertical field. Clearly, this effect can be used to monochromatise a polarised neutron beam. Here we propose a novel design of such a magnetic resonator consisting of a sequence of separate compact modules, which provide high homogeneity of the transversal field oscillations and allow rapid beam chopping since they meet the specifications of fast electronic switching. The wavelength resolution of this resonator device can be changed in an instant and likewise an arbitrary amplitude modulation of the transversal field can be established, which is required for an efficient suppression of subsidiary maxima of the wavelength-dependent spin flip probability.     

Design details and characterization of all digital closed-loop interferometric fiber optic gyroscope with superluminescent light emitting diode

This paper describes the design details and the characterization of an all digital closed-loop (ADCL) interferometric fiber optic gyroscope (IFOG) Prototype with sine wave biasing modulation and SLED emiting at 1288.9 nm, constructed in TUBITAK UME. Electronic feedback section of ADCL-IFOG is composed of 16 bit AD7714YN ADC, 14 bit-LTC1667CG DAC, fully controlled and synchronized by 89C51 microcontroller. The averaged sensitivity of the ADCL-IFOG prototype in unit of error voltage applied to the phase modulator was calculated as 132.65 μV/(°/h) which equals to a scale factor of 7.53888 (°/h)/mV with a standard deviation of 0.85% for a range of 1–15270 (°/h) rotation rate, corresponding to a range of Sagnac phase shifts varying from 0.00115 to 17.57448 (°). The maximum peak to peak noise and the bias stability of the prototype were determined as 4.97 and 1.48 (°/h) at 23.0°C, respectively. The variation of the noise and bias stability on a temperature range of 23.0–42.0°C was observed.