基于夹层结构的偏振无关1×2定向耦合型解复用器的设计

提出一种基于夹层结构的偏振无关1×2定向耦合型解复用器,用于分离1310 nm和1550 nm两个波长.通过合理选择夹层结构芯区的折射率及波导间隙,可以调节同一波长两个正交偏振模的耦合长度相等,实现偏振无关;通过合理选择夹层结构波导宽度,可以使两个波长分别从不同输出波导端口输出,实现解复用功能.运用三维有限时域差分法进行建模仿真,对结构参数进行优化,并对器件性能进行了分析.结果表明:该器件定向耦合波导的长度为23μm,插入损耗低至0.1 dB,输出波导间的串扰低至–26.23 dB,3 dB带宽可达290 nm和200 nm.另外,本文提出的器件采用Si3N4/SiO2平台,可有效减小波导尺寸,提高集成度,不仅实现了偏振无关,而且结构紧凑、损耗低,在未来的集成光路中具有潜在的应用价值.     

光波导-光纤自动调芯系统研究

设计了两种适用于光波导高精度自动对接耦合的调芯方案,从原理上克服了常规调芯过程中微变信号精确测试的困难。完成了调芯系统的光机电一体化、控制程序和接口界面。单模光纤作为标准波导的端面耦合自动凋芯试验显示,平均耦合损耗分别为0．075 dB(1310nm波长)和0．062 dB(1550nm波长),相应的标准误差分别为0．0099 dB和0．0066 dB．调芯过程在2min内完成。单模光纤-单模波导-单模光纤的对接耦合实验结果表明,端面耦合损耗平均值分别为0．140 dB(1310nm波长)和0．109 dB(1550nm波长),标准误差分别为0．0082dB和0．0107dB,调芯时间累计不超过8min。     

基于SU-8聚合物的越级衍射型单纤三向波分复用器

介绍了基于阵列波导光栅(AWG)的单纤三向波分复用器的设计、仿真、制作与测试。利用阵列波导光栅的频谱周期性,采用越级衍射方法可在无需改变AWG布局,无需额外元件的情况下覆盖三向波分复用器的整个工作波段(1310~1550nm)。器件的芯层采用较高折射率的SU-8聚合物,下包层是二氧化硅,并用空气作为覆盖层,制作流程简单,只需要紫外光刻,成本低。仿真结果显示三个工作通道3dB带宽都大于11nm,偏振波长漂移不超过0.65nm。器件测试结果验证了越级衍射设计的正确性,在TM偏振态下的第二和第三波长通道的额外损耗是3dB左右,第一波长通道的额外损耗是7dB左右,串扰在-15dB左右。整个器件大小仅1.3mm×0.402mm。     

紧缩型含氟聚酰亚胺多模干涉波分复用器的FD-BPM分析

为了减小波分复用器的器件长度,在聚酰亚胺材料的基础上,设计了一种赝态结构的2×2多模干涉波分复用器,并分别用精确导模分析法对其进行模拟分析和优化设计。结果表明,赝态结构波分复用器可以有效地对980nm和1550nm光进行解复,并且器件尺寸只有传统设计的1/5。器件在器件长度和波长变动中显示出良好的容差性,并且能够和掺铒放大器与激光器实现集成。其中,赝态结构MMI聚酰亚胺波分复用器的干涉区宽度和长度以及输入口宽度和距离对其性能均有影响。     

基于硅基二氧化硅阵列波导光栅宽带低串扰单纤三向器

采用硅基二氧化硅阵列波导光栅设计并制作了宽带低串扰单纤三向器.为使三个波长间隔相差较大的输出谱获得相同的带宽,在输出波导与罗兰圆交界采用了不同结构的多模干涉器.二维有限差分束传播法的模拟结果表明,理论上1310nm、1490nm和1550nm波长的3dB带宽分别达到23nm、23.5nm和25nm,插入损耗均为4dB,1310nm波长的串扰小于-40dB,1490nm与1550nm波长间串扰小于-40dB;采用宽带光源测试结果表明,1550nm波长的3dB带宽为23nm,采用三个独立窄带光源测试结果表明,三个波长的插入损耗均为7dB,1310nm波长的串扰小于-40dB,1490nm与1550nm波长间的串扰小于-39dB,测试与模拟结果基本一致.     

跑道型结构光子晶体波导定向耦合器

鉴于波导定向耦合器在集成光路以及光电集成方面的广泛应用,提出了一种基于光子晶体波导间高效耦合的光子晶体定向耦合器。通过主波导和耦合波导间的耦合,可以实现对波长为1 490 nm和1 550 nm电磁波的高效分光。在将器件长度控制在30 μm左右的同时,其总效率高达93.05%。另外,发现主波导和耦合波导间介质柱结构参数对电磁波的耦合周期有着极大的影响。并通过将介质柱沿z方向拉伸0.1a(a为晶格周期),设计了工作波长为1 530 nm和1 540 nm的光子晶体定向耦合器,器件长度仅为60 μm。通过拉伸介质柱的纵向长度,可以大幅减小耦合周期,这对缩小器件体积以及实现更为密集的波分复用有着重要的意义。     

A Novel Fabrication for Method Long PeriodFiber Grating

A new method of fabricating all-fiber broadband-rejection filter based on long period fiber grating (LPFG) is proposed. The principle in the method is to make periodic asymmetrical deformation in the core of fiber without microbends by electrode discharging so as to induce periodic refractive index changes. Two kinds of filters whose rejection peak wavelength at 1550 nm and 1310 nm are obtained. The insertion loss is less than 0.6 dB and 1.4 dB respectively. The 20 dB bandwidth ranges from 10 nm to 39 nm. The backward reflection loss is extremely small (less than - 70 dB). Such devices can be used as isolation filters in 1310/1550 nm WDM system and other fields.     

通过以太无源光网的射频电视传送技术

论述了1550 nm射频电视(CATV)通道与1490 nm数据通道的相互干扰问题。针对1490 nm光波通过光纤中受激拉曼效应对1550 nm光波的非线性串扰和1550 nm光波通过粗波分复用(CWDM)分波器对1490 nm光波的线性串扰提出了理论计算公式,进行了定量分析和计算。结果表明,数据非线性串扰可使射频电视系统低频端的载噪比下跌9 dB;而在常规融锥型粗波分复用分波器情况下,射频电视线性串扰可使数据光接收机的光功率代价达到2.5dB。最后指出了克服串扰的方法,如以太空闲字符扰码和高隔离度粗波分复用等。     

基于Si3N4/SiNx/Si3N4三明治结构的偏振无关1×2多模干涉型解复用器的设计

提出一种基于Si3N4/SiNx/Si3N4三明治结构多模干涉波导的偏振无关1×2解复用器,用于分离1310和1550 nm两个波长.通过合理选择三明治结构中间层SiNx的折射率,可以调节同一波长两个正交偏振态的拍长相等,实现偏振无关;根据多模干涉原理,通过合理选择多模干涉波导的长度与宽度,可以使两个波长的输出像点分别成正像和反像,实现解复用功能.运用三维有限时域差分法进行建模仿真,对结构参数进行优化,并对器件关键结构参数的制作容差进行了分析.结果表明:该器件多模干涉波导的尺寸为4.6μm×227.7μm,插入损耗低至0.18dB,输出波导间的串扰低至–25.7dB, 3dB带宽可达60 nm.另外,本文提出的器件采用Si3N4/SiO2平台,可有效减小波导尺寸,提高集成度,不仅实现了偏振无关,而且结构紧凑、损耗低,在未来的集成光路中具有潜在的应用价值.     

聚合物弥散液晶材料在1550nm的电光特性研究

实验研究了不同配方及工艺条件下,聚合物弥散液晶（PDLC）材料在1550nm处的电控光透射特性。由此筛选合适的配方和工艺,研制了聚合物弥散液晶电控可调光衰减器样品。实验说明,在1550nm工作点,50％左右合适的液晶含量的聚合物弥散液晶样品能够获得更好的电控光学性能。采用配方质量比ω（DHPA）：ω（E7）：ω（RB）：ω（NVP）：ω（NPG）=100：100：3：2：1．5的配方,制作在1550nm工作的聚合物弥散液晶光衰减器样品。经检测,输入光源为1550mm,223μW时,器件插入损耗为2．3dB,衰减调节范围为13dB,线性工作区域为20～70V。     

Multimode interference wavelength multi/demultiplexer for 1310 and 1550 nm operation based on BCB 4024-40 photodefinable polymer

A 1310 and 1550 nm coarse wavelength multi/demultiplexer based on benzocyclobutene (BCB 4024-40) polymer is demonstrated for the first time. The device is designed based on a combination of general interference and paired interference mechanisms of multimode interference (MMI). It is fabricated on BK7 glass substrate with a thin layer of SiO₂ as cover. A cost effective chemical etching technique is used in the fabrication process to take advantage of the photosensitive nature of the polymer. The device length was significantly reduced by adopting the restricted multimode interference scheme, lower beat length ratio and cascaded MMI couplers. The measured crosstalk at 1310 nm was 14.4 dB and at 1550 nm was 20.6 dB. The measured insertion loss is around 3.2-3.5 dB for both ports.     

单模光纤1250～1650 nm超平坦宽带耦合器

随着光纤技术的飞速发展和应用．光纤无源器件顺应当前形势也获得很大的发展空间,其中光纤熔锥器件具有制作简单、性能可靠、价格便宜及技术指标优越等优点,从而广受青睐。在熔锥器件中,光纤耦合器是广为应用的基础元器件。目前为实现全光通信。光纤超平坦宽带耦合器则成为热点课题。利用特殊相位补偿工艺方法,研制出单模光纤超平坦宽带耦合器。其工作波长范围为1250～1650nm,3dB带内最大插损偏差小于等于0．4dB,带内最大附加损耗小于等于0．1dB,方向性(输入侧非注人光的一端的输出光功率与注入光功率的比值)大于等于66．5dB,偏振相关性小于等于0．1dB。研制方法有很高的成品率,可批量生产。     

1x2 Multimode interference couplers based on semiconductor hollow waveguides formed from omnidirectional reflectors

A 1x2 hollow multimode interference (MMI) coupler based on semiconductor hollow waveguides formed from omnidirectional reflectors (SHOW-ODR) is demonstrated. The device has a shorter coupling length than a conventional silicon-on-insulator MMI coupler. A 2 dB uniformity was achieved at operating wavelengths between 1520 and 1562 nm. The device exhibited a weak polarization dependence in the TE and TM modes.     

熔锥型宽带耦合器的研制

介绍了全光纤熔融拉锥型3dB宽带耦合器的理论设计，根据理论设计制作了样品。应用耦合模理论分析了全光纤非对称熔融拉锥型耦合器的宽带特性；提出了3dB宽带耦合器的制作方案，在此基础上制作了样品；对样品进行测试，样品带宽大约为300nm(在1300nm～1600nm波长之间)，附加损耗小于0.5dB，完全达到了实用化的要求。     

Characteristic Analysis of a Smooth Square Microring Resonant Wavelength Multiplexer

Novel formulas of amplitude coupling ratio and transmission functions are presented for a smooth square microring resonant (MRR) wavelength multiplexer. By using these formulas, transmission characteristics are analyzed and some parameters are optimized for such a 1 × 8 polymeric device around the central wavelength of 1550.92 nm with the wavelength spacing of 1.6 nm. In the design of the device, by using the smooth squares, a thicker coupling layer is obtained, and by resonating the light at different resonant orders in different filter elements, the ring radius increment is increased sufficiently, which is of benefit to the fabrication of the device. When the amplitude coupling ratio is 0.2, the 3-dB bandwidth of the spectral response is about 0.2 nm; the ratio between -1 dB and -10 dB bandwidths is about 0.2; the insertion loss is less than 1.33 dB; and the crosstalk is below -21 dB for every vertical output channel of the device.     

Wide, tunable band rejection filter based on micro-optical waveguide on microactuating platform covering O, E, S, C, L, and U bands

An ultrawide, tunable band rejection filter was experimentally demonstrated operating from 1060 to 1670 nm seamlessly covering all communication bands (O, E, S, C, L, and U bands). The device consists of a micro-optical waveguide made from fused taper fiber coupler mounted over a microactuating platform that systematically applies a highly localized torsional stress over the coupling region. High-band rejection efficiency of 20-30 dB and very low insertion loss of 0.2 dB were experimentally achieved over the whole operating spectral range.     

利用改进的熔融拉锥法制备单模光纤波分复用器

研究了熔融拉锥光纤型波分复用器制备过程中各相关参量对其最小信道间隔的影响。并根据理论模拟的结论设计了新型的熔融拉锥装置,其中加热装置为有较长均匀加热区域的条形加热炉,使熔融拉锥光纤型波分复用器的耦合长度显著加长,改善了传统拉锥方法对这一类型波分复用器可达到的最小信道间隔的限制,得到了初步实验结果,最小信道间隔达到3.01 nm。     

Efficient and compact TE-TM polarization converter built on silicon-on-insulator platform with a simple fabrication process

An efficient TE-TM polarization converter built on a silicon-on-insulator nanophotonic platform is demonstrated. The strong cross-polarization coupling effect in air-cladded photonic-wire waveguides is employed to realize the conversion. A peak TE-TM coupling efficiency of 87% (-0.6 dB insertion loss) is measured experimentally. A polarization conversion efficiency of >92% with an overall insertion loss of <-1.6 dB is obtained in a wavelength range of 40 nm. The proposed device is compact, with a total length of 44 μm and can be fabricated with one lithography and etching step.     

Surface plasmon polaritons based optical directional coupler

As a basic optical device, the optical directional coupler (ODC) is basically used as optical splitters, optic switches and so on. A novel ODC employing surface plasmon polaritons (SPPs) is proposed for high integration. The finite difference time domain (FDTD) method is adopted to simulate and analyze its properties. Results show that the ODC proposed here follows the general regulations of a conventional dielectric ODC, but its transverse size is of nanoscale, which improves the optical integration greatly. For 1550 nm and 1310 nm input wavelengths, when the coupling region length (L) equals half of its coupling length, the Excess Loss is respectively 0.57 dB and 0.56 dB, which is practical in applications. So the research on the present ODC is of some practical importance.     

一种电光可调的铌酸锂/钠基表面等离子体定向耦合器

为了满足日益增加的集成光子器件设计的需求,本文研究了一种铌酸锂/钠表面等离子体波导(Li Nb O3/Na surface plasmonic waveguide, LNSPW),并利用LNSPW构成电光可调的定向耦合器(directional coupling,DC).利用有限元方法 (finite element method, FEM)对波导的模式特性和耦合器的耦合特性进行了分析.结果表明,随着波导尺寸的增大,传播长度可达约200μm,归一化有效模场面积小于0.4.通过调节耦合间距(W_gap)、耦合长度(L_C)和工作波长(λ)等参数,铌酸锂钠表面等离子体波导构建的定向耦合结构可实现3 d B耦合.当W_gap=100 nm和L_C=17μm时, DC在V₀=53 V时可实现3 d B耦合,且具有较好的方向性和隔离度.LNSPW的研究为实现可调的DC提供了一种可行的方案,在集成电光可调器件研究领域有潜在的应用前景.除此之外, LNSPW还可广泛应用于非线性光学、光信号处理及光全...