儿童青少年健康成长是每位家长最为关注的焦点.本文阐述我国教室照明的现状,分析照明对学生用眼的影响,相关质量标准亟待规范的迫切性,以及对比国内外技术标准差距,探讨利用LED平板灯具改善教室照明的设计与系统方案,提出改善思路与途径,意在促进教室照明用灯具的质量提升.

基于元数据的概念与产品核心元数据要素,阐述国内外元数据研究成果及现状,本文选取照明产品核心元数据标准化典型案例,针对照明产品核心元数据标准化体系提出建议,从应用层面聚焦产品核心元数据规范及展望标准应用前景.

A novel optical power monitoring method based on optoelectronic oscillators incorporating semiconductor optical amplifiers is presented and a prototype of two nodes distributed online optical power monitor with dynamic measuring range of 6dB and accuracy of 0.25dB is experimentally demonstrated.

A composite electromagnetic absorber for anechoic chambers is proposed with the structure consisting of a pyramidal foam and a lossy frequency selective surface (FSS) structure. Simulation results show that the period of absorber array and the pyramid base impact directly on absorption nulls, and the effects of pattern size, surface impedance and substrate thickness of FSS are more complicated due to interactions between the pyramidal foam and FSS structure. Two examples are discussed and the results show that improved absorption below 3GHz can be achieved by properly selecting parameters.

Battery management system (BMS) takes a key role in battery health management and life extension of electric vehicles. It contains various analogue-digital hybrid circuits above the frequency range of several hundred mega-Hertz, where the signal integrity and system stability are probably affected by certain issues of circuit design. In this report, the signal reflections along the transmission lines in a BMS are theoretically simulated and analyzed. The performance of the system is compared to that after optimization both in theory and measurement. The simulation and experimental results verify that electrical impedance matching is most crucial to the signal integrity and system stability in the system design.

Electromagnetic shielding effectiveness of metallic enclosure influences the EMC performance of EV-BMS (electric vehicle-battery management system). Electromagnetic leakage of electric equipment enclosure caused by apertures is a serious problem. In this chapter, the numerical simulation analysis for electromagnetic shielding performance of enclosure with apertures is performed based on Finite Element Method. Different shapes and orientation of aperture/slot bringing to shielding effectiveness and resonant frequency are analyzed, and analysis of the influence on the shielding performance of the enclosure by the different location of aperture is conducted as well. Meanwhile, some improving counter measures are proposed. By comparing different schemes of BMS metallic enclosure, the chapter provides guidelines for designing the enclosure.

By using the Babinet modeling theory and the finete element simulation software,the problem of slot radiation of enclosure is discussed.Firstly,the factor of the slot with different aspect ratio on radiation is analyzed,and that with different locations is analyzed too.Secondly,the method of inhibiting slot radiation is studied.

This paper presents a numerical simulation method based on FDTD algorithm to solve long testing period and complex process of SAR measurement. Dipole antenna and Flat Phantom were modeled. Simulation was done in the range of 300MHz to 3GHz. The simulation result was compared with IEEE-1528 reference value and error sources were analyzed. The result indicates the feasibility of numerical simulation method based on FDTD algorithm.

PIC chip refers to the one that has several functional devices based on the same substrate material, which has strong adaptability to environmental factors, such as vibration and temperature. The application of PIC chip in the node and terminal equipment of the optical communication can greatly enhance the equipment's ratio of performance over the price and reduce the volume. In this paper a three-dimension time domain method is employed as simulation instrument to design the strip EAM with a ring resonator on InP/InGaAsP-MQW, and the chip is produced by applying domestically advanced semi-conductor epitaxial growth and etching techniques, and it has passed the static test, which shows that the modulator has obvious electric absorption effects and the filtering peak of the resonator changes with the variation of offset voltage.

Based on four-port resonator filter theory,parallel rectangular standing wave and parallel round traveling wave resonator optical filters are simulated and optimized using 3D-FDTD(three dimensional finite-difference time-domain) method on PML(perfectly matched layer) boundary condition.GaAlAs/GaAs planar waveguide filters based on four-parallel-rectangle standing wave resonator,on single ring traveling wave resonator and on three-parallel-ring traveling wave resonator are tested.The measurement result is in accordance with the computation well.

With the 81910A photonic all-parameter tester from Agilent Company the chromatic dispersion characteristics of strip InP/In1-xGaxAs1-yPy-multiple-quantum-well electro-absorption-modulator(MQW-EAM)with different component ratios are studied,and the bandwidth of EAM is estimated.The research results show that the dispersion characteristics of III-V semiconductor MQW-EAM are closely related to materials.Therefore,the materials for semiconductor photonic devices with the same type applied to high-speed optical communication system must be accordant to the greatest extent,so as to ensure the consistency of high-speed performance of semi-conductor photonic devices.

Simulation calculation is performed on the filtering characteristics of GaAlAs/GaAs single ring resonator respectively by 3D-FDTD simulation algorithm and SI-system identification algorithm, and the compared results show that the filtering characteristics of the filter obtained by the two algorithms are basically identical with each other.Compared with 3D-FDTD algorithm,SI algorithm can save a certain amount of time in calculation and can be used as a kind of effective auxiliary design method for planar waveguide resonator filter.GaAlAs/GaAs planar waveguide single ring resonator filter is designed and manufactured based on the analog simulation.The filtering characteristics of the simulation calculation filter tally well with the test results of real device. FWHM is about 13 nm.

Based on a parabolically tapered multimode interference (MMI) coupler with a deep-etched SiO2/SiON rib waveguide, a compact wavelength demultiplexer operating at 1.30 and 1.55 μm wavelengths is proposed and analysed by using three-dimensional semi-vectorial finite-difference beam propagation method (3D-SV-FD-BPM). The results show that a MMI section of 330.0 μm in length, which is only 76% length of a straight MMI coupler, is achieved with the contrasts of 42.3 and 39.2dB in quasi-TE mode, and 38.4 and 37.8dB in quasi-TM mode at wavelengths 1.30 and 1.55 μm, respectively, and the insertion losses below 0.2dB at both wavelengths and in both polarization states. The alternating direction implicit algorithm with the Crank–Nicholson scheme is applied to the discretization of the 3D-SV-FD-BPM formulation along the longitudinal direction. Moreover, a modified FD scheme is constructed to approximate the resulting equations along the transverse directions, in which the discontinuities of the derivatives of magnetic field components Hy and Hx along the vertical and horizontal interfaces, respectively, are involved.

Traveling wave(TW)electrode structure is widely used for it needs less multi-action length between optical carrier and digital modulation and can get rid of contribution capacity's constraints on modulation bandwidth.Based on time domain method,TW electrode on InP/InGaAsP electronic absorption modulator is simulated,analyzed and compared with the fabrication on characteristic impedance Z_c and loss coefficientα.The numeric results calculated by time domain method coincide with measurement well.Characteristic impedance is about 45Ω,and the loss coefficient is less than 4 dB/mm from DC to 20 GHz.

提出了一种改进的三维全矢量有限差分虚位移束传播法,用以分析光波导承载的全矢量本征模.在纵向(z向)离散上,第一个子步采用半矢量公式,而第二个子步采用全矢量公式,但交叉项双倍计算.每个横向电场分量在两个子步中的次序交换,交叉项用隐式形式表示,计算效率高且稳定.在横向(x和y向)离散上,基于多项式插值法,建立了一种统一的差分格式,考虑了电场法向分量在芯包分界处的不连续性,可应用于均匀和非均匀网格,差分系数引入了更多邻近节点的折射率分布,且交叉项采用六点差分格式,计算精度高,程序通用性强.首先分析了高折射率分布差的矩形、GaAs/GaAlAs双异质结脊形光波导,给出了全矢量基模及次高阶模(矩形波导)的电场分布及其归一化传播常数,揭示了全矢量本征模的混合特性,验证了该方法的有效性.接着分析了InP基InGaAsP/InGaAsP应变多量子阱脊形光波导,考虑了深刻蚀和浅刻蚀两种情形,讨论了其全矢量基模的模式特性,为设计以此为基础的光子集成回路奠定基础.

Polarization Dependent Loss (PDL) accumulated by devices such as optical modulators,switches,filters,isolators in fiber-optic communications system remarkably degradated the transmission property of the whole link so that PDL of passive components became an important specification parameter.PDL of M-Z modulator influenced by stress between InP/In_ 1-x Ga_xAs_ 1-y P_y-MQW and its substrate and hence the Polarization Mode Dispersion(PMD) represented by Differential Group Delay(DGD) were first experimently observed by Agilent 81910A Photonic All Parameter Analyzer.The outcome shows PDL and DGD of semiconductor Multiple-Quantum-Well(MQW) are consistent.During the fabrication of semiconductor optical devices,the residual stress between InP/In_ 1-x Ga_xAs_ 1-y P_y-MQW and its substrate should be lessened as greatly as possible to avoid its impact on high speed optical devices′ performance.

Tapered and lensed fiber (TLF) is the key device to couple optical energy from optical fiber into planar lightwave circuits (PLC) high-efficiently. To understand and grasp TLPs focusing performance is pivotal for PLC pigtail packaging technology. The theoretical analysis model of output beam spot diameter and far-field divergence angle, which are principal parameters to represent TLF's focusing characteristics, is put forward. The error of the model falls within 1.14%. Lightwave propagation and mode field evolution are simulated by finite-difference beam propagation method so that the spot diameter is ascertained. TLF's taper length, half core taper angle, and lens curvature radius are optimized to be 300 μm, 0.733°, 13.485 μm respectively. The focusing beam spot is observed by digital video camera experimental setup and calculated using an inverse deducing method from physical optics. The theoretical and measurement results are consistent. For a specific TLF sample, the spot diameter value by inverse deducing method is differed from the theoretical one with error of 3.15%, and the error for far-field divergence angle is 3.67%.

A modified alternating direction implicit approach is proposed to discretize the three-dimensional full-vectorial beam propagation method (3D-FV-BPM) formulation along the longitudinal direction. The cross-coupling terms (CCTs) are neglected at the first substep, and then double used at the second substep. The order of two substeps is reversed for each transverse electric field component so that the CCTs are always expressed in an implicit form, thus the calculation is efficient and stable. Based on the multinomial interpolation, a universal finite difference scheme with a high accuracy is developed to approximate the 3D-FV-BPM formulation along the transverse directions, in which the discontinuities of the normal components of the electric field across the abrupt dielectric interfaces are taken into account and can be applied to both uniform and non-uniform grids. The corresponding imaginary-distance procedure is first applied to a buried rectangular and a GaAs-based deeply-etched rib waveguide. The field patterns and the normalized propagation constants of the fundamental and the first order modes are presented and the hybrid nature of the full-vectorial guided-modes is demonstrated, which shows the validity and utility of the present approach. Then the modal characteristics of the deeply-and shallow-etched rib waveguides based on the InGaAsp/InGaAsP strained multiple quantum wells in InP substrate are investigated in detail. The results are necessary for modeling and the design of the planar lightwave circuits or photonic integrated circuits based on these waveguides.

A 3D trapered spot-size converter(3D-SSC) on a rib cross-sectional optical waveguide, one of the key components in photonic devices connecting with single mode optical fibers,is investigated through simulating lightwave transmission in this component based on 3D-FD beam propagation method.Geometry parameters,such as laterally boundaries,length,width of the large section,thickness and those of the transitional optical waveguide for connecting SMOF to 3D-SSC are discussed and analyzed.The simulation shows that the insert loss of 3D-SSC can be lower than 2?dB as the width in the area of 11.5?μm～13.5?μm and the thickness in the area of 4.5?μm～6.5?μm at the large end of the taper when the taper length is in the region of 200?μm～500?μm.The capability and the alignment tolerance of the 3D-SSC is better than those of the planar SSC,and the 3D-SSC with a nonlinear lateral boundary acquires lower insertion loss than that with a linear lateral boundary.It is found that the 3D-SSC converts gradually the guided modes from multi-mode to single mode finally.

从慢变包络(SVEA)时域光传输方程出发,对比了综合道格拉斯(GD)和传统的中心差分(CN)两种离散化格式,指出GD法比CN法精度有了很大提高.重点讨论了GD法的TD-BPM边界处理问题,给出了吸收边界和透明边界离散的显式和隐式表达式,分析并确定了交替方向隐式法(ADIM)的边界处理方式;同时,对激励源加入的连接边界进行了仔细讨论.结果表明对于隐式GD-TD-BPM法边界处理应采用隐式,中间激励更能反映光波导反射场的情况.