反射光路的计算机辅助装调模型

对反射光路中可能出现的两个反射镜之间的空间位置关系进行了分析。基于直角坐标系中的坐标变换原理,推导法线平面平行、法线平面垂直、法线空间垂直三种位置关系下反射镜组的光路模型,作为指导计算机辅助装调的模型依据。利用Matlab对光路模型进行仿真,更直观的指导装调。     

计算机辅助的光学装调方法

本文介绍了一个利用了干涉计量实测系统的波前,结合扫描透镜模型的微分光束,使得设计和实测波前之差趋于零以便确定对透镜系统的装调过程。多视场可以用来说明误差的原因,这些误差是随着视场变化的并且在调节变量的数目上是根本不受限制的。调整参数比较典型地包括倾斜度,偏心度和透镜或透镜组的轴向运动。阻尼最小二乘法用     

差分吸收光谱仪光路装调专用三维调整机构

差分吸收光谱仪具有114°×0.5°的视场、0.3～0.5 nm的高光谱分辨率、13 km×48 km的高空间分辨率的技术指标要求,为了达到这些技术指标,不仅需要光学系统设计满足这些要求,也需要专门的平台用于装调光谱仪的光学系统。基于差分吸收光谱仪装调需求,研制了三维调整机构用于装调光谱仪的光学系统,三维机构分为升降维、偏转维和悬臂旋转维。升降维可以在竖直方向上下调节,且可达到0.05mm的分辨率,满足光谱仪位置调节需求。偏转维可以实现4-3°左右摆动,且可以实现3’的分辨率,满足光谱仪0.5°视场的需求。悬臂旋转维可以实现竖直面内±62°的旋转,通过两级蜗轮蜗杆运动传递实现5"的高分辨率,满足覆盖114°光源输入的调节。     

计算机辅助装调的代理模型方法

用代理模型实现了一个新的失调量求解方法,可在较大失调范围内进行更为准确的求解。首先分析了基于灵敏度矩阵方法求解失调量的原理和局限性,提出了使用代理模型求解失调量的设想。在代理模型方法中,设定光学元件各个自由度对应的失调范围,对各自由度失调量进行大量的蒙特卡洛仿真得到充足的样本模型。然后从样本模型中提取失调量和残余像差数据,其中残余像差数据用Zernike 系数表示。对比三种不同的代理模型,选择用人工神经网络表示失调量与残余像差之间的非线性映射关系或统计关系。最后用一个离轴三反射系统模拟装调的例子,说明了如何建立代理模型,并根据当前系统的状态进行调整,表明了使用代理模型进行辅助装调的实用性和可靠性。     

R-C光学系统的计算机辅助装调

R-C光学系统是现代光学工程中常用的光学系统,以某一R-C光学系统为例,对其计算机辅助装调技术进行了研究。分析了R-C系统装调理论,确定以主镜为装调基准,调整次镜五个自由度的装调方法,建立起次镜失调量与系统Zernike系数的关系,以此指导装调工作,达到明确装调方向、缩短装调周期的目的。整机光学系统的波像差RMS值优于1/10波长,达到了成像质量的要求。对相机进行实验室和地面外场成像,获得的图像图像清晰,层次丰富,验证了装调工作的正确性。     

基于DWC波前检测的计算机辅助装调技术

计算机辅助装调(CAA)技术是提升高精度、复杂离轴光学系统成像质量的有效手段.介绍了计算机辅助装调技术发展背景及现状,总结了用于计算机辅助装调技术的光学检测手段及优化方法.介绍了一种基于高分辨率波前传感器(DWC)的计算机辅助装调技术,建立了数学模型.这个模型包含光学系统出瞳波面像差获取、失调光学系统的失调量计算及系统像差表示三个方面的内容.最后,对模型进行了数值仿真试验,通过对比系统装调前后的结果,验证了该方法的理论可行性.     

光学系统计算机辅助装调分析与应用

光学系统的计算机辅助装调（CAA）技术自20世纪80年代提出,从90年代开始在各个国家得到发展并逐渐运用到各个领域。在此简要介绍了计算机辅助装调技术及其装调过程,并推导了CAA的数学模型。通过广泛调研国内外计算机辅助装调的发展与应用,比较了各国成功应用CAA技术完成的装调。分析了目前国内CAA技术的发展状况,对传统装调方法和CAA方法的适用情况做了比较,为我国计算机辅助装调提供借鉴。     

库德光路的五棱镜安装方法

为实现库德光路的快速高精度装调,提供了一种基于自准直原理的五棱镜安装方法,给出了库德光路的原理和安装方法,并对组装后的库德光路进行误差分析。得出应用此方法安装库德光路的光学静态误差在15″以内,满足一般库德光路的技术要求。因此,此方法不仅可以适用于库德光路,对反射镜的安装也有一定的借鉴和参考。     

离轴三反系统计算机辅助装调

为实现对离轴三反系统快速、有效的装调,提出了一种离轴三反系统计算机辅助装调（CAA）方法。该方法在理论分析失调后离轴三反系统像差特性的基础上,结合CAA技术及光学装调的实际情况,选择出最少且最合理的调整量;根据检测数据及CAA数学模型直接计算出调整量的大小及方向。采用该方法对一离轴三反系统进行实际装调,将调整量从11个减少到7个,利用波前传感器被动式检测方法对离轴三反系统0及1视场像质进行检测,通过一次计算调整快速使该系统全视场波像差从RMS0.32减少至RMS0.067（=632.8 nm）,结果表明该装调方法简单、有效。     

New spatial quadrature modulation scheme forindoor visible light communication systems

In this paper, a new spatial quadrature modulation ( NSQM ) scheme is proposed to improve the error performance of indoor visible light communication ( VLC) systems. NSQM is different from generalized spatial quadrature modulation ( SQM) in two aspects. First, the transmitted optical signal is directly detected at the receiver, which does not need to estimate the indices of the transmitted antenna. Second, an optimization approach is used with NSQM to minimize the upper error bound of the transmitted signals. In addition, several NSQM schemes are described in detail. Numerical results show that the proposed NSQM scheme achieves superior error performance compared with the SQM scheme.     

采用光束扫描的透射仪测量光路自动准直系统

能见度是航空、航海及其他领域关系到安全保障的重要气象要素之一,透射式能见度仪在安装和使用过程中测量光路的准直状态,对能见度测量精度有重要影响。根据其光学系统的特点提出了一种基于扫描方式的透射仪测量光路自动准直方法,并基于该方法设计了自动准直系统。系统通过电机驱动发射端探测光束与接收端接收视场分别在两个垂直方向上进行扫描,计算发射端与接收端的准直方位角,进而实现透射仪测量光路的对准。系统测试表明,系统可以实现透射仪测量光路的自动对准,方位角定位最大误差为66rad,准直时间小于10 min,系统具有准直精度高、过程自动化、易于安装等特点。     

Interference alignment scheme for massive MIMO system

The performance of massive multiple-input multiple-output （MIMO） system is limited by pilot contamination. To reduce the pilot contamination, uplink and downlink precoding algorithms are put forward based on interference alignment criterion. In the uplink receiving processing, the target function aligns the pilot contamination and the interference signals to the same null space and acquires the maximal space degree of the desired signals. The uplink receiving precoding matrix is solved on maximal signal to interference plus noise ratio （SINR） criterion considering the impact of the pilot contamination on channel estimations. The uplink receiving precoding matrix is used as the downlink transmitting precoding matrix. Exploiting the channel reciprocity, it is proved that, if the uplink receiving precoding matrix achieves maximal S1NR, the identical precoding matrix can be used in the downlink transmission and acquires maximal signal to leakage plus noise ratio （SLNR）. Simulations show that the spectrum efficiency of the proposed algorithm can reach about 1.5 times higher than that of popular matched filtering （MF） precoding algorithm, and about 1.1 times higher than multi-cell minimum mean square error （MMSE） precoding algorithm. The performance of the proposed algorithm can be improved approximately linearly with the increasing of the number of antennas.     

High-resolution spatial light modulation with distributedphotorefractive devices

We present a new photorefractive multiple-quantum-well (MQW) spatial light modulator design in which the electrooptic region is made of periodic subdevices with smaller electrooptic regions. We show that the spatial resolution of the new device, which we refer to as a distributed-photorefractive device, is a factor of two higher than a comparable conventional device. Furthermore, our data indicates that the spatial resolution depends on the subdevice thickness instead of whole device thickness. We also show that by placing smaller subdevices closer toward the electrodes, where the fringing fields are high, and larger subdevices closer to the central region of the modulator, device sensitivity can be increased without considerably reducing the spatial resolution     

High-speed spatial light modulator

A high-speed, coherent spatial light modulator is under development. It is based on the coupling of a silicon photodiode and electrooptic crystal. The design criteria and theoretical performance are presented. Optical quality oflambda/20rms atlambda = 500nm over a 1 in aperture has been demonstrated. Submicrosecond write and erase rates are predicted. Heat dissipation limits the predicted continuous rate to 2.5 kHz or higher, depending on required optical quality. Calculated phase MTF is 50 percent at 10 cycles/mm.     

基于空间光调制器的灰度掩模制作环形光栅

介绍了基于空间光调制器的灰度掩模系统制作环形光栅．将二元光学方法与环形光栅的概念结合起来,为制作可以集成到光电系统的环形光栅以及其他光学元件提供了一条较好的思路．     

光寻址空间光调制器技术

空间光调制技术广泛应用于阈值开关、高速光互连、光逻辑运算等领域,对光信号的实时快速寻址有极高的要求。与电寻址方式相比,光寻址采用并行寻址,速度快,分辨率高,具有更大的优势。但在实际应用中,如何实现快速稳定的光寻址成为空间光调制的关键。本文以Zn O薄膜作为光导层,构造光寻址液晶空间光调制器,更好地实现了对读出光光强和相位的二维空间分布的调制。     

A disjoint path selection scheme with shared risk link groups in GMPLS networks

This letter proposes a disjoint path selection scheme for generalized multi-protocol label switching (GMPLS) networks with shared risk link group (SRLG) constraints. It is called the weighted-SRLG (WSRLG) scheme. It treats the number of SRLG members related to a link as part of the link cost when the k-shortest path algorithm is executed. In WSRLG, a link that has many SRLG members is rarely selected as the shortest path. Simulation results show that WSRLG finds more disjoint paths than the conventional k-shortest path algorithm.     

一种基于波束赋形的空分复用MIMO接收方案

提出一种基于波束赋形(BF)的空分复用多输入多输出(MIMO)接收方案,该方案兼具MIMO多流接收和 BF抗干扰的优点。针对平坦衰落信道,建立了基于空间相关的 BF-MIMO接收系统模型,推导出了系统接收误码率表达式,阐明了角度扩展与系统抗干扰性之间的关系。理论分析和仿真结果表明,该接收方案在小角度扩展条件下较普通 MIMO 系统具有更优的抗干扰和误码率性能。     

Drive circuit for spatial light modulator with software preprocessing unit

A drive circuit, with software preprocessing unit, is developed for Multi-quantum-well (MQW) spatial light modulator (SLM). According to the characteristic values of different SLM reflective properties, software preprocessing unit fits the curve of reflectivity spectra for the modulator and generates photoelectric-conversion-controlling signals, which improve the commonality of the drive circuit. A new method of scanning was researched in this paper to substitute the old method of one-step scanning. The new method, that rough-scan is followed by fine-scan, could achieve high scanning speed and high output resolution. Apart from this, it could also effectively reduce the pixel size to be integrated with MQW SLM by flip-chip bonding. SPICE simulation and chip test results show that, the chip could work well, and the swing of drive voltage is from 0 to V _DD , the resolution of drive voltage could be up to 256. In a word, this circuit could meet the requirements of MQW SLM.