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1.
聚合物脊形光波导的变分有效折射率法分析 总被引:2,自引:1,他引:1
聚合物脊形光波导是聚合物集成光电子器件的重要构成单元.利用有效折射率法计算聚合物脊形光波导的横向折射率分布及有效折射率,将各区域中的光场分布近似用分段函数表达.基于导模满足的标量波动方程,利用变分法确定变分参量,以求得准确的横向光场分布.对聚合物脊形多模光波导基模和高阶模的色散特性与横向场分布进行分析,研究了波导结构参数对色散特性的影响,计算出TM基模和高阶模的光场分布,得出了聚合物脊形光波导的单模传输条件.研究表明,该方法计算量小、精度高,对聚合物光电子器件中脊形光波导的理论分析与设计优化提供了简单高效的方法. 相似文献
2.
铁电SBN薄膜电光系数的测量及其在波导中的应用 总被引:2,自引:0,他引:2
利用溶胶-凝胶法在MgO(001)衬底上获得C轴择优取向的铁电铌酸锶钡(SBN)薄膜,主要介绍MgO(001)衬底上SBN60薄膜及掺入的K离子与Nb离子摩尔比例为1:3的SBN60薄膜横向电光系数r51的测量,实验测得不掺K的SBN60薄膜r51值为37.6pm/V,掺K的r51值为58.5pm/V。并由此设计一种基于MgO(001)衬底上的马赫一曾德尔型SBN60薄膜波导调制器,计算出在633nm时,掺K比例为1:3的此种波导调制器半波调制电压值为10V,不掺K的半波电压值为16V,结果说明掺入K离子能增加薄膜的横向电光系数并有效的减少波导的半波调制电压。 相似文献
3.
Berkhout GC Lavery MP Courtial J Beijersbergen MW Padgett MJ 《Physical review letters》2010,105(15):153601
We present a method to efficiently sort orbital angular momentum (OAM) states of light using two static optical elements. The optical elements perform a Cartesian to log-polar coordinate transformation, converting the helically phased light beam corresponding to OAM states into a beam with a transverse phase gradient. A subsequent lens then focuses each input OAM state to a different lateral position. We demonstrate the concept experimentally by using two spatial light modulators to create the desired optical elements, applying it to the separation of eleven OAM states. 相似文献
4.
V. K. Abrahamyan N. H. Hakobyan V. M. Aroutiounian N. V. Kamanina H. L. Margaryan D. L. Hovhannisyan D. K. Pokhsraryan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2009,44(6):283-290
Influence of the longitudinal voltage applied along the semiconductor substrate of a planar-oriented liquid crystal cell on
the birefringence of a nematic liquid crystal (NLC) was investigated. It is shown that for a fixed magnitude of the transverse
field the application of a longitudinal voltage creates an additional possibility to control the electro-optically induced
phase incursion of the radiation passing through NLC. Dependence of the phase incursion on the control voltages is obtained.
The results of simulation of the longitudinal voltage effect on the NLC reorientation are described. The obtained results
can be used in development and designing of NLC phase modulators. 相似文献
5.
M-Z光波导是聚合物电光调制器的重要结构单元。利用有效折射率法计算聚合物脊形波导的横向折射率分布,将三维光波场传播简化为二维传播。从导模满足的标量波动方程出发,结合透明边界条件,采用Crank-Nicholson差分格式,得出有限差分束传播法的基本计算格式。通过对M Z型波导结构中TM模的传播及损耗特性进行理论分析,系统地研究了脊宽、分支角等结构参数对损耗的影响。研究表明,有效折射率法与二维有限差分束传播法的结合可以较好地解决脊形M Z波导的设计问题。该方法具有精度高、计算量小及效率高等优点,为聚合物电光调制器的制备提供了理论依据。 相似文献
6.
《Optik》2014,125(24):7215-7221
Tapered waveguide are used in number of integrated optic devices such as directional couplers, modulators, switches mode converters, etc. Most of the methods analyzing tapered waveguide are numerical in nature. In this paper we present a simple, fast and accurate semi analytical method for z-varying waveguide. However, very few idealized structures can be analyzed directly. The present method consists of separating transverse and longitudinal variation in the wave equation, leading to a differential equation with z-varying coefficients for the field variation along z-axis. For the transverse variation local normal theory is applied. Now this equation is applied to specific taper geometries like linear down taper. Computational are done assuming typical values. We observe variation of power mode profile and mode width. Waveguide loss is also including in the analysis. Finally the analytical simulation results have been verified by the commercial Opti-BPM software. 相似文献
7.
A.S. Andrushchak B.G. Mytsyk N.M. Demyanyshyn M.V. Kaidan O.V. Yurkevych S.S. Dumych A.V. Kityk W. Schranz 《Optics and Lasers in Engineering》2009,47(1):24-30
The electro-optic (EO) properties of pure and MgO-doped LiNbO3 crystals are characterized by indicative surfaces (IS) describing the spatial anisotropy of the longitudinal and transverse linear EO effects. By analyzing the IS and their stereographic projections, we have determined the geometries with maximum EO coupling. The maximum magnitudes of the linear EO effect are revealed in the longitudinal and transverse geometries along the directions that substantially deviate from the principal crystallographic axes of both crystals. Spatial analysis of the IS thus yields a set of the optimized sample geometries recommended for designers who develop EO modulators or deflectors. Just by switching from the standard cell geometry to the optimized cell geometry, as determined in the present work, one may improve almost three times the modulation efficiency of EO devices based on lithium niobate crystals. This results in a corresponding reduction of their driving voltages being evidently of great practical importance for many applications. 相似文献
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利用折射率椭球分析法,分析了某些具有多重光学效应的光学晶体在两个外场同时作用下的一些特有调制规律.结果表明,当晶体的折射率椭球方程的三个交叉项中只有一项x1x2不为零时,可以得到其外场诱导新主轴折射率及其主轴取向的简单计算式.据此可以揭示出某些晶体在两个外加电场同时作用下将具有双横向电光Pockels效应,例如ˉ6点群的电光晶体.但一般晶体在双横向应力作用下不具有与双横向电光效应类似的调制特性,其弹光双折射大小与其应力差成正比,其双折射主轴方向一般为固定值.在相互垂直的外加应力和电场同时作用下,某些晶体(例如ˉ43m点群晶体)的双折射大小与外加应力和外加电场的加权几何平均值成正比,且新折射率主轴旋转角由外加应力和外加电场的比值来确定.晶体的上述双参量调制特性对设计新型光学调制器或传感器具有重要指导意义. 相似文献
10.
Semiconductor waveguide optical switches and modulators are reviewed from the view point of material and structure. As material for switches and modulators, effects of both variations of refractive index and absorption are considered. As for the structure of switches and modulators, basic characteristics of devices, including length, speed, and consumption power, are investigated, and recent experimental performances are shown. For further improvement of switches and modulators, the importance of low-dimensional quantum-well structures and strained quantum-well structures are pointed out. 相似文献
11.
S. Koshevaya I. Moroz V. Grimalsky M. Tecpoyotl-Torres J. Escobedo-Alatorre J. Sánchez-Mondragón 《International Journal of Infrared and Millimeter Waves》2005,26(3):387-408
Volume and based on surface oriented integrated p-i-n-structures modulators have demonstrated high efficiency in millimeter wave range as quasi-optical modulators and phase shifters. These structures possess high modulation and high-speed properties; sustain great EM powers. However, the modulation characteristics of p-i-n modulators of both mentioned types in millimeter wave range have not been investigated yet. Here, a comparison and criteria of volume and integrated based on Si surface oriented structure modulators in millimeter wave range are presented. 相似文献
12.
Advanced optical modulation formats are a key technology to increase the capacity of optical communication networks. Mach-Zehnder modulators are typically used to generate various modulation formats. Here, we report the first experimental demonstration of quadrature phase-shift keying (QPSK) modulation using compact microring modulators. Generation of 20 Gb/s QPSK signals is demonstrated with 30 μm radius silicon ring modulators with drive voltages of ~6 V. These compact QPSK modulators may be used in miniature optical transponders for high-capacity optical data links. 相似文献
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Haibo Peng Boyu Wu Qiong Song Fei Lu Shuyun Luo 《International Journal of Infrared and Millimeter Waves》2003,24(9):1587-1596
Hybrid electrode combined coplanar waveguide (CPW) and microstrip lines in ultra-broadband electro-optic modulators. The characteristics of the modulators with hybrid electrode is like that of the modulator with the microstrip lines, in which the microstrip electrode is loaded above only one arm of Mach-Zehnder (M-Z) optical waveguide, besides the problem of microstrip line to coaxial transition and corona polarization in polymer modulators have been best solved at the same time. By using finite element method (FEM), the characteristic parameters such as half-wave voltage, modulation bandwidth characteristic impedance, effective microwave refractive index of polymer modulators with microstrip line and hybrid electrode are analysed and compared in this paper. The results present that velocity match, impendence match and lower microwave propagating loss is easily realized in modulators with hybrid electrode. 相似文献
15.
We investigate the transmission performance of N × 40 Gbps carrier-suppressed return-to-zero (CS-RZ) and duobinary CS-RZ (DCS-RZ) modulated wavelength division multiplexed (WDM) signals over the standard single-mode fiber (SSMF) based on non-ideal Mach-Zehnder (MZ) modulators through numerical simulations. In addition to that, the impact on receiver margin related to the residual chirp due to an asymmetry ratio of modulators as well as the effect of the applied chirp of modulators has been studied. As the asymmetry ratio of modulators is increased, dispersion penalties are increased asymmetrically at around the zero dispersion wavelength for the CS-RZ format. The DCS-RZ modulation format has a symmetric behavior due to different characteristics of the residual chirp of modulators. The receiver margin for the DCS-RZ modulation format is larger than the CS-RZ modulation format above the asymmetry ratio of 0.82 of modulators (extinction ratio of 20 dB) with the optimal ΔλDCF. By controlling the negative/positive applied chirp of the first/second modulator, dispersion penalties can be reduced for both the CS-RZ and DCS-RZ formats. In the DCS-RZ format compared to the CS-RZ format, the effect of the applied chirp of the first modulator is more dominant than that of the second modulator. The simulation results show that the receiver margin is limited by the asymmetry ratio of modulators as well as a deviated wavelength from the zero dispersion wavelength of dispersion compensating fibers (DCF) in order to be fully post-compensated. Dispersion penalties can be reduced with appropriate chirp parameters of two non-ideal modulators. 相似文献
16.
The optical carrier suppression in optical quadruple frequency modulation by cascaded external modulators is investigated theoretically and experimentally. Theoretical analysis demonstrates that the optical carrier suppression ratio is related with not only the initial phase difference of electrical signals applied on the two modulators, but also the optical phase shift between the two modulators. The maximum suppression ratio can be achieved when the total phase difference is equal to nπ+π/2 (n = 1, 2,…), which is verified by experiments. By properly controlling the total phase shift, 40-GHz millimeter-wave is generated by using a 10-GHz radio frequency (RF) source and the modulators. 相似文献
17.
SeveralPhaseModulatorsforDigitalShearography¥F.CHEN,Y.Y.HUNG(DepartmentofMechanicalEngineering,OaklandUniversity,RochesterHil... 相似文献
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Lin Zhang Yunchu Li Muping Song Jeng-Yuan Yang Raymond G. Beausoleil Alan E. Willner 《Applied Physics A: Materials Science & Processing》2009,95(4):1089-1100
Electro-optic modulation plays a critical role in implementing space-, power- and spectrally efficient optical interconnection
for high-capacity computing systems. Microring resonators exhibit a great potential to achieve compact, low power-consumption
and high-speed modulators. In this paper, we briefly review our efforts on designing and analyzing the microring modulators.
Three types of single-ring modulators are discussed, from device behavior to possible system impact. We then present two novel
double-ring modulators in which a passive ring resonator is added, enabling higher operation speed and lower power consumption.
We also describe an opportunity of introducing phase modulation data formats into the on-chip communication environment. In
this paper, our emphasis is placed on linking the devices’ physics to their system performance and providing potential technical
solutions to physical-layer challenges of optical interconnection. 相似文献
20.
The results of calculations of main parameters of a slot-type electrodynamic system taking into account losses in a single-mode nonresonance regime of excitation and in the regime of responance excitation in the vicinity of the cutoff frequency are presented. Analytic expressions obtained for the transmission coefficient, resonance frequency, and transmission band can be used in designing wide-band optical modulators. Experimental verification of laboratory prototypes of electrodynamic systems and their application in available modulators confirms the possibility of employment of such analysis for choosing optimal designs of ultrahigh-frequency modulators of optical radiation. 相似文献