非球面镜补偿器的支撑结构设计

为了折叠光路、减小系统像差,空间遥感器的光学系统经常需要使用非球面镜。在非球面镜的光学检测中,补偿器的支撑结构是不可缺少的设备。在定义补偿器的自由度和坐标系的基础上,结合补偿器在非球面镜检测光路中的位置和作用,分析了调节补偿器需要的自由度。基于自由度分析结果,确定了支撑结构应实现的功能和结构形式。论述了一种支撑结构的结构设计,并给出了该支撑结构的调节精度分析结果。分析结果表明,该支撑结构的位移调节精度为1.4 μm/deg,角度调节精度为0.007 μrad/deg。实际的工程应用表明,该支撑结构能满足使用要求。     

应用干涉仪对经纬仪光学系统主镜的装调和检测

随着光电经纬仪的跟踪精度、图像像质质量等技术指标的提高,使光学系统的装调和检测要求也随之提高,传统的装调方法不能够满足新形势下经纬仪的安装精度需求。文中介绍了一种应用干涉仪对经纬仪系统主镜的装调和检测方法,分别从主镜的装配、调整、镀膜、光轴中心检测与校验对主镜的装调思路进行分步骤介绍。应用ZYGO干涉仪对主镜系统检测,从传统的刀口仪、显微镜的定性检测方法上升为使用ZYGO干涉仪对系统的定量检测。检测测试结果说明,应用干涉仪对经纬仪光学系统的检测完全满足光学设计的指标要求,从观察70～80 km航空飞机和5000 m目标靶图像看到目标的图像清晰,图像的边缘对比度好,满足使用要求。干涉仪在经纬仪光学系统主镜装调中的应用,满足高精度经纬仪的需求,从而提高主镜装调精度。     

8～12μm波段折/反/衍混合坦克扫描物镜消热差设计

根据坦克扫描光学系统的要求,设计了一种工作于8～12μm波段,可识别2 000 m远坦克目标的折/反/衍射混合红外消热差光学系统。该系统采用新型的卡塞格林系统,其非球面主镜和次镜全部取代为球面,解决了卡塞格林系统大口径非球面主镜、次镜的高加工精度和装调难的问题;通过应用衍射元件独特的温度特性实现红外光学系统的无热化设计,设计的系统结构简单紧凑,口径大、焦距长、分辨率高,并且在-40～60℃的温度范围内成像质量接近衍射极限,满足坦克扫描系统的总体要求和像质要求。     

大口径非球面计算全息图检测系统

为了精确地检测大口径非球面面形质量,将曲面圆形计算全息图与补偿镜相结合,应用于非球面折射式检测光学系统中.分析了曲面计算全息图的衍射特性,同时分别阐述了利用曲面计算全息图的这种衍射特性来检测凹非球面及凸非球面的基本原理和方法,给出了具体的设计实例.与传统的非球面检测光学系统相比较,该系统不仅简化了传统光学系统的装调过程,还可以大大降低计算全息图（CGH）与补偿镜的制作精度,减少制作成本.尤其是在凸非球面检测过程中,首次在实验技术方面提出了两步全孔径检测法和调整误差的旋转相减消除法,实验验证了该方法的有效性.     

计算全息图检测大口径凹非球面系统的研究

根据圆形计算全息图的衍射特性，将曲面圆形计算全息图与补偿镜相结合，应用于凹非球面折射式零检测光学系统中。与传统的折射式零检测光学系统相比，该系统不仅可以简化光学系统的装调过程，还可以降低计算全息图与补偿镜的制作精度，减少制作成本。阐述了利用曲面计算全息图衍射特性的折射式零检测光学系统检测凹非球面的基本原理，给出了具体的设计实例。对于口径为950 mm的抛物面，检测结果P-V值为0.024λ。     

离轴光学系统封装技术的研究

针对某型号头盔显示器光学系统的封装要求,研究了光学镜片的加工、检测及装配工艺特点,提出了一种能很好解决离轴光学系统装配难题的方法,并结合现代制造工艺水平,设计了相应的五自由度装调设备。经误差分析及控制系统对导轨误差的主动补偿,设备的角度调整精度为3.15,位移调整精度约为1 m。光学镜筒采用曲面造型,为薄壁对开式结构。选用铝合金材料,装配完成后单个镜筒总质量195 g,最大应力为1.5 MPa,最大变形0.3 m,满足设计要求。     

一种易于制造的空间相机光学系统设计

空间技术的不断发展对空间相机光学系统的设计不断提出新的要求,为了提高相机系统的可靠性,对系统的面型加工精度有更高的要求。介绍了一种易于制造的空间相机光学系统,基于R-C系统,设计了含有三块球面校正镜组件的折反式光学系统。结果表明,该光学系统在空间频率50 lp/mm处,调制传递函数均大于0.4,主镜和次镜均为二次曲面,其余均为球面,具有易于制造装调等优点。     

星载激光测距仪扩束系统的高精度装调

星载激光测距仪扩束系统为无焦系统,对光学装调有着苛刻的要求,装调精度是决定激光测距仪工作能力的关键因素。利用计算机辅助装调技术,确定光学系统对光学元件的敏感度和补偿调整参量。针对镜间距影响该系统性能参数的特点,提出采用高精度三坐标测量技术和双光路定心技术对扩束系统装调。最后,采用 1 064 nm干涉仪对光学系统像质进行测试,使用套孔法对束散角进行测量。测试结果表明:该星载激光测距仪扩束系统RMS优于0.225,束散角为0.41 mrad,满足设计要求。     

双光纤相移点衍射干涉仪装调技术

为了实现对极紫外光刻物镜系统波像差的超高精度检测,引入了双光纤相移点衍射干涉仪,介绍了其工作原理,并对干涉仪的装调方案进行了精密的设计。解决了各个元器件的精确定位问题,保证了进入光纤之前的测试光和参考光严格垂直, 实现了耦合系统与光纤之间最大的耦合效率和干涉条纹最大的条纹对比度, 为最终能够实现极紫外光刻物镜系统波像差的超高精度检测提供了前期准备。装调完毕后,利用实验装置对某一光学系统进行了测量,使用十三步相移算法还原被检光学系统波像差,得到了较好的结果,测试结果为:PV 值为37.82 nm,RMS 值为7.83 nm。     

宽光谱可见-短波红外成像光学系统设计

针对目前的红外成像光学系统在机器视觉工业检测领域难以同时实现成像质量好和结构紧凑设计的问题,提出了一种宽光谱可见-短波红外成像光学系统的设计方法。运用光学设计软件ZEMAX设计了一种适用于可见光和短波红外的红外成像光学系统。该系统由7组10片透镜组成,利用多组双胶合透镜来消色差,在第15个面使用非球面提高成像质量,最后对系统的成像质量进行研究。设计结果表明：该系统的的工作波长为0.4～1.7μm,全长为79.6 mm,F数为2.8,焦距为25.7 mm,畸变小于1.4%,调制传递函数值在奈奎斯特频率100 lp/mm处均大于0.4,接近衍射极限,成像质量良好。该系统可以对光滑表面的装配件进行缺陷检测,具有结构简单、易于加工装调的优点,有助于高效地完成机器视觉检测。     

40 GHz phase shifter based on semiconductor laser

This investigation experimentally demonstrates a 40 GHz phase shifter based on a semiconductor laser. The phase shift is achieved by adjusting the bias current and wavelength detuning. The device has an optical delay of 23 ps and a phase shift of about 331deg.     

Fluidic Assembly of Optical Components

A self-assembly technique is used to match microscopic components in a desired configuration with a high degree of precision. The basis of this self-assembly technique is capillary forces that are used to assemble the micro components. A liquid solder provides the capillary forces by wetting a 3-D cavity in each of the parts to be assembled. An advantage of the proposed design is that the high degree of precision of the mating feature relative to the optical guides ensures a high degree of concentricity of the optical path in the device. The application presented is the self-assembly of arrays of single-mode optical fibers onto an optical chip for use in optical switches or tunable filters. Optical measurements revealed an insertion loss of less than 0.85 dB, which demonstrates misalignment in the order of 1 mum     

A Two-Wafer Approach for Integration of Optical MEMS and Photonics on Silicon Substrate

This letter reports a novel two-wafer approach which demonstrates an integration of optical microelectromechanical system (MEMS) devices and photonics on a silicon substrate. The great advantage of this novel wafer bonding scheme is the ability to maintain the optical axis of the optical MEMS device at the same axis as the optical components. The bonded two wafers which are partially processed, which allows for further processing on the wafer after bonding. Thus, the critical alignment issue is resolved for devices requiring precise alignment in x-/y-/z-axis. Individual functionalities of optical MEMS device and optical coupling between silicon waveguide, fibers and ball lens are demonstrated. This technology shows the potential for integrating silicon photonics integrated circuit and MEMS components with reconfiguration functions on a single silicon substrate.      

40Gb/s光纤链路的可视化建模及仿真研究

通过全数值计算方法,建立了40 Gb/s单信道传输链路的可视图形化模型.详细描述了光源、传输链路、光探测及判决单元的建模原理及求解方法,并对预啁啾归零码(CRZ)的传播过程进行了仿真研究,为教学演示及实验提供了良好、经济的仿真平台.     

双光频梳辅助的微波频率测量方法北大核心CSCD

为实现大频率范围内多微波频率的高精度即时测量,提出了一种基于双光频梳和法布里-珀罗滤波器(Fabry-Perot filter,FPF)的微波频率测量方案。将待测微波信号通过单边带调制加载在一路光频梳上进行频率复制,再将调制后的光信号通过一个法布里-珀罗滤波器进行信道分割。FPF的输出信号和另一路光频梳耦合后通过光解复用器实现信道化接收。通过设置合适的系统参数,可使得每个信道输出的拍频信号在同一窄带中频频段内。基于频率-光功率映射的原理,通过判断信号的存在性即可确定未知信号所处的频率段,实现信号频率的粗估计。通过对目标信道输出的微波信号进行采样、模数变换和信号处理可实现未知信号频率的高精度测量。通过实验仿真验证了所提方案的有效性,频率测量误差在±2.5 MHz内。     

Quantum-well SEED optical oscillators

Oscillation at 110 MHz in a GaAs-GaAlAs quantum-well SEED (self-electrooptic effect device) optical oscillator is considered. Optimization of device length and optical pump wavelength for high-frequency oscillation is discussed. Frequency tuning is obtained by adjusting the oscillator bias voltage or optical pump power, and the oscillator can be injection locked to modulated optical signals. Frequency fluctuations caused by perturbative Gaussian noise and 1/f frequency noise are observed; the 1/f noise in an 8.5-MHz oscillator limited the minimum frequency variance to 230 Hz²     

High-frequency, stripline, multireflection electrooptic beam deflectors

A novel electrooptic (EO) beam deflector has been designed through numerical simulation. This stripline lithium tantalate device has the potential to electrooptically modulate the deflection of an optical pulse at unprecedented frequencies. Velocity matching of the optical pulse to a high-frequency transmission line signal is achieved through reflections of the fast optical pulse. An optimal design criterion is formulated for this device. Deflection capability is estimated to be 8/spl deg/. The device is intended for use in deflection-based optical analog-digital (A/D) conversion.     

Laterally actuated torsional micromirrors for large static deflection

We report on the implementation of laterally electrostatically actuated, torsionally suspended silicon-on-insulator (SOI) micromirrors with a static optical deflection angle of over 40/spl deg/ peak-to-peak. Decoupling the actuator and mirror design allows for large actuator arrays, allowing large dc deflection angle and high resonant frequency to coexist in the same device. The micromirror structures are fully monolithic, micromachined from the front side and back side of an SOI wafer-device layer. In-plane actuation is transformed into out-of-plane motion and rotation, enabling integration of a wide variety of SOI-MEMS sensors, actuators, and micromirrors. When operated in resonance at 1321 Hz, a typical device measured up to 92/spl deg/ peak-to-peak optical deflection at 127 Vdc with 15 Vac amplitude.