抑制噪声的宽带碲基掺铒光纤放大器性能分析

设计了一个带光隔离器的复合型宽带碲基掺铒光纤放大器（EDTFA），通过对该结构模型下的速率方程和光功率传输方程组的数值模拟，理论研究了EDTFA在插入光隔离器后的性能变化。研究表明，通过插入光隔离器抑制反向传输的放大自发辐射（ASE）噪声，可以有效地改善宽带EDTFA的信号增益和噪声特性。在光纤激活长度240cm、铒掺杂浓度2000ppm和前向泵浦功率200mW下，光隔离器插入在最佳位置处时，1540nm～1600nm波段内16路信道小信号增益分别提高了0.8dB～5．9dB，噪声系数降低了0.2dB～2．2dB。研究结果对于新型宽带EDTFA应用于WDM通信系统中具有理论指导意义。     

胶辊式砻谷冲击振动隔离器力学特性研究

针对胶辊式砻谷冲击隔离的需求,设计一种砻谷辊冲击振动隔离器,组成六个隔离器并联构成的隔离系统,进行砻谷辊冲击振动隔离系统力学特性研究。建立冲击隔离系统静力学模型,获得系统刚度特性及系统初始静平衡位置保持力的静力学方程,分析辊内六连杆隔离器的刚度特性,结果表明,隔离系统的径向力关于胶辊中心轴线对称,胶辊的偏移量x 对系统刚度影响很小,系统保持力随预压缩比e 增大而增大。建立运动学模型,对隔离系统所受激励力进行傅里叶变换,采用杜哈曼积分法求出了隔离系统的响应表达式,分析了隔离系统的响应,结果表明,隔离系统的响应频率与脉冲激励频率一致,偏移量x 在（-0.09 mm～0.29 mm）之间,最大偏移量为0.29 mm。该研究为胶辊式砻谷的冲击振动隔离提供理论支持。     

八连杆抗冲击隔离器设计与性能分析

为提高惯性导航设备的抗冲击能力,设计了一种八杆并联的抗冲击隔离器,能够大幅度降低来源于任意方向的冲击载荷。该结构具有隔冲杆组利用率高、隔冲效果好的特点。分析其横、纵向隔冲原理,得出该结构横、纵向刚度一致,其杆组与冲击方向的夹角范围更小,载荷分配更均匀;首先,通过螺旋理论计算整体结构的空间自由度,证得八连杆抗冲击隔离器结构合理;在此基础上,利用ADAMS仿真软件对比了六、八连杆结构的水平向抗冲击性能,得出八连杆抗冲击隔离器的隔离效果更显著;接下来,讨论了冲击载荷及阻尼参数对隔离器的影响,并计算了被隔离设备在垂向、横向冲击载荷下的加速度响应;最后对隔离器进行垂向及横向冲击试验,对比并分析响应结果,得出该隔离器的垂、横、纵向隔离效果满足抗冲击要求。     

双光纤保偏准直器结构研究与参数设计

双保偏光纤准直器在远距离的光纤通信系统中得到广泛的应用.本文从理论上分析了光在自聚焦透镜中的传播规律,推导出光线在自聚焦透镜中的传输矩阵,分析了自聚焦透镜斜端面的角度与准直器的插入损耗和回波损耗设计结构,并通过实际的装配进行验证.用这种方法设计的双光纤保偏准直器具有低的插入损耗(小于0.3dB),和高的回波损耗(大于60dB),己成功应用于光环行器中.     

地回路电流引起的干扰电压对射频相移测量的影响

一、引言相位或相移测量通常是指测量两个同频率振荡之间的相位差。因此,无论采用何种原理的相位计都具有参考通道和测量通道。在射频范围内,用标准相移器或标准延迟线校准相位计时,必须使用隔离器或衰减器进行两通道间的隔离,以防止通道之间产生交叉耦合,提高校准准确度。有关双通道法相移校准系统的各种交叉耦合,已有很详细的分析。但是以     

一种用于通信C波段的光轨节点无源集成芯片

光轨是一种新型光通信网络结构,具有交换粒度小、带宽利用率高等优点。本文提出一种应用于通信C波段的新型光轨节点无源集成芯片,支撑1 545 nm、1 550 nm和1 555 nm三个C波段波长的通信。该新型光轨节点无源集成芯片是一种基于SOI纳米波导材料的片上微器件系统,核心器件由基于微环谐振器的解复用器和基于马赫-泽德尔干涉仪的环加强型热光光开关构成。通过理论计算和软件仿真,分别分析了解复用器和光开关的光学和通信性能,结果显示微环解复用器3个波长信道的串扰分别为22.5 dB、16.9 dB和16.3 dB;光开关的消光比分别为16.6 dB、19.7 dB和21.5 dB;插入损耗分别为0.86 dB、0.85 dB和0.68 dB,功耗约为51 mW。     

胶辊式砻谷冲击振动隔离器力学特性研究

针对胶辊式砻谷冲击隔离的需求，设计一种砻谷辊冲击振动隔离器，组成六个隔离器并联构成的隔离系统，进行砻谷辊冲击振动隔离系统力学特性研究。建立冲击隔离系统静力学模型，获得系统刚度特性及系统初始静平衡位置保持力的静力学方程，分析辊内六连杆隔离器的刚度特性，结果表明，隔离系统的径向力关于胶辊中心轴线对称，胶辊的偏移量x 对系统刚度影响很小，系统保持力随预压缩比e 增大而增大。建立运动学模型，对隔离系统所受激励力进行傅里叶变换，采用杜哈曼积分法求出了隔离系统的响应表达式，分析了隔离系统的响应，结果表明，隔离系统的响应频率与脉冲激励频率一致，偏移量x 在（-0.09 mm～0.29 mm）之间，最大偏移量为0.29 mm。该研究为胶辊式砻谷的冲击振动隔离提供理论支持。     

玻璃基掩埋式光波导堆栈的制作与表征

在硅酸盐光学玻璃基片上制作了光波导堆栈,这种光波导堆栈通过Ag+/Na+熔盐离子交换和电场辅助离子扩散技术顺次制作了两层掩埋式光波导.对光波导堆栈的横截面显微结构进行了观察,并对堆栈中两层波导的损耗特性进行了测试.所获得的光波导堆栈中的上、下两层波导芯部分别位于玻璃表面以下14和35μm处;上层光波导芯部尺寸约为12μm×7μm;下层光波导芯部尺寸约为9μm×8μm.通光测试显示两层波导在1.55μm工作波长下均为单模光波导,且两者之间没有相互耦合.损耗测试分析结果显示:堆栈中两层光波导的传输损耗均约为0.12 dB/cm,与单模光纤之间的耦合损耗分别为0.78和0.73 dB.分析表明,这种光波导堆栈在玻璃基集成光芯片的高密度集成方面具有很好的应用前景.     

无源对称光学结构双通道光纤旋转连接器

提出一种实现双通道旋转互连的新型对称光学耦合结构,并应用光学结构设计出无源双通道光纤旋转连接器。利用自聚焦透镜发射光信号,使其通过自由空间传输,被另一个自聚焦透镜接收。在自由空间可以实现旋转连接并实现光信号的双向传输,通过分析该光学结构设计原理和光路计算,发现每组透镜中两个透镜焦距之比为 20?50,离轴距离为 4?10mm 范围时,才能保证光信道之间不发生干扰且信号持续传输。     

自由空间光到保偏光纤的耦合方法

光纤通信技术具有高带宽和低损耗等特点,广泛应用于民用和军用领域,而把空间光高效率耦合到光纤传播是首要问题。本文根据模式匹配理论研究了空间光-保偏光纤光耦合的方法,理论上得到模式匹配的透镜焦距和距离,进一步在实验上通过模式匹配透镜来实现高斯光束光斑形状的匹配来实现633nm和543nm激光的耦合,实验结果表明在不计算光纤本身插损的前提下耦合效率最大达到73%。     

On chip optical isolator based on non-linear silicon photonic crystal by using asymmetric engineering waveguide

We propose an optical isolator formed in a nanoscale structure based on non-linear silicon photonic crystal that can be easily realized on an optical integrated chip. The structure comprises an engineered waveguide that is coupled to a L₂ cavity. By using a passive ultra-compact cavity-based isolator, without changing incident characteristics such as mode or frequency in outputs, an admirable transmission contrast of 20.5 dB with a small insertion loss (in the forward direction) of ?14.8 dB is achieved. The isolator attains a broad isolating linewidth operation of 0.9 nm without bistability response that is outstanding in comparison with the currently proposed cavity-based isolators. The non-linear Fano resonances that are created by the interplay between the non-linearity and spatial asymmetry notion in the structure play a critical role in the isolator efficiency. In this study, the finite-difference time-domain and finite element methods are used for simulations.     

Magneto-optical non-reciprocal devices in silicon photonics

Silicon waveguide optical non-reciprocal devices based on the magneto-optical effect are reviewed. The non-reciprocal phase shift caused by the first-order magneto-optical effect is effective in realizing optical non-reciprocal devices in silicon waveguide platforms. In a silicon-on-insulator waveguide, the low refractive index of the buried oxide layer enhances the magneto-optical phase shift, which reduces the device footprints. A surface activated direct bonding technique was developed to integrate a magneto-optical garnet crystal on the silicon waveguides. A silicon waveguide optical isolator based on the magneto-optical phase shift was demonstrated with an optical isolation of 30 dB and insertion loss of 13 dB at a wavelength of 1548 nm. Furthermore, a four port optical circulator was demonstrated with maximum isolations of 15.3 and 9.3 dB in cross and bar ports, respectively, at a wavelength of 1531 nm.     

Integrated optical polarization splitter based on photobleaching-induced birefringence in azo dye polymers

An integrated optical polarization splitter has been fabricated by utilizing the photobleaching-induced birefringence in an azo dye polymer. It consists of a Y-branch waveguide formed by the reactive ion etching with one of the two arms photobleached. The refractive index of the photobleached arm is decreased for the TE mode and increased for the TM mode. The performance of the splitter was measured as a function of the energy of the photobleaching beam and compared to a wave propagation simulation of the device. The measured cross talks are less than -28 dB for the TM mode and -24 dB for the TE mode at a wavelength of 1310 nm. The measured excess losses for the TE and TM modes, which measure the effect of the Y branch and the photobleaching, are 0.3 and 0.4 dB, respectively. The insertion loss was 5 dB, which includes the input fiber to waveguide coupling loss.     

Coupling and cross-talk effects in 12-15 microm diameter single-mode fiber arrays for simultaneous transmission and photon collection from scattering media

We examine signal degradation effects in fiber arrays from fiber-to-fiber coupling and from cross talk attributable to backscatter from the sample medium originating from adjacent fibers in the array. An analysis of coupling and cross talk for single-mode fibers (SMFs) operating at 1310 nm with different core diameters, interaction lengths, core center spacing, and numerical apertures (NAs) is evaluated. The coupling was evaluated using beam propagation algorithms and cross talk was analyzed by using Monte Carlo methods. Several multimode fiber types that are currently used in fiber image guides were also evaluated for comparative purposes. The analysis shows that an optimum NA and core diameter can be found for a specific fiber center separation that maximizes the directly backscattered signal relative to the cross talk. The coupling between fibers can be kept less than -35 dB for interaction lengths less than 5 mm. The calculations were compared to an experimentally fabricated SMF array with 15 microm center spacing and showed good agreement. The experimental fiber array without a lens was also used in a coherent detection configuration to measure the position of a mirror. Accurate depth ranging up to a distance of 250 microm from the tip of the fiber was achieved, which was five times the Rayleigh range of the beam emitted from the fiber.     

Demonstration of a multichannel optical interconnection by use of imaging fiber bundles butt coupled to optoelectronic circuits

Through five experiments, we demonstrate and characterize the basic functionality of imaging fiber bundles for optoelectronic chip-level interconnections. We demonstrate the transmission of spot arrays with spot sizes and a spot pitch roughly equal to 2 and 4 times the core pitch, respectively. We show that optoelectronic integrated circuits, including sources and detectors, can be butt coupled directly to fiber bundles without any additional optical elements. We demonstrate a 16-channel interconnect with -23 dB of cross talk, and we characterize the most significant optical loss mechanism. Finally, we show how imaging fiber bundles can be used to implement more complex interconnection structures by an example of a hybrid-bonded structure that implements a low-cost, high-connectivity solution for more advanced system architectures.     

Bending loss of elliptical-hole core circular-hole holey fibers bent in arbitrary bending directions

A holey fiber having a core with an elliptical-hole lattice structure, which is referred to as an elliptical-hole core circular-hole holey fiber (EC-CHF), can be easily designed as a single-polarization fiber by using the fundamental space-filling modes of the core and cladding lattices. However, because the guided mode in an EC-CHF has a polarization that arises from the large geometric anisotropy of the core lattice, the influence of the bending direction on the bending loss is a crucial issue for the practical implementation of EC-CHFs. Here, the bending losses of an EC-CHF bent in arbitrary angular orientations with respect to the core cross section are calculated numerically using the equivalent anisotropic step-index circular fiber model for a real EC-CHF, and the influence of the bending direction of the fiber on the bending loss is discussed.     

Interconnection of a two-dimensional array of vertical-cavity surface-emitting lasers to a receiver array by means of a fiber image guide

The implementation of a 10-channel parallel optical interconnect consisting of a two-dimensional array of vertical-cavity surface-emitting lasers, a 1.35-m fiber image guide, and a metal-semiconductor-metal receiver array is described. Transmission rates of 250 Mbits/s per channel are demonstrated with an optical cross talk of less than -27 dB and a loss of -3 dB. Coupling issues associated with image guides are analyzed and discussed.     

Tapered chalcogenide–tellurite hybrid microstructured fiber for mid-infrared supercontinuum generation

Fibers exhibiting flattened and decreasing dispersion are important in nonlinear applications. Such fibers are difficult to design, particularly in soft glass. In this work, we develop a preliminary design of a highly nonlinear tapered hybrid microstructured optical fiber (TH-MOF) with chalcogenide glass core and tellurite glass microstructure cladding. We then numerically studied its dispersion, loss, and nonlinearity-related optical properties under fundamental mode systematically using the infinitesimal method. The designed TH-MOF exhibits low chromatic dispersion that is similar to a convex function with two zero-dispersion wavelengths and decreases with fiber length from 2 to 5 μm band. The potential use of the TH-MOF in nonlinear applications is demonstrated numerically by a supercontinuum spectrum of 20 dB bandwidth covering 1.96–4.76 μm generated in 2-cm-long TH-MOF using near 3.25-μm fs-laser pump.     

聚合物光纤网络器件及其通信链路系统

通过自行研制的聚合物光纤波长转换器和集线器,实现了石英光纤传输介质到聚合物光纤传输介质的工作波长转换,以及多路聚合物光纤传输信息的交换和局域网信息的全聚合物光纤传输。系统测试结果显示,数据交换传输速率达到100Mbps,通信眼图清晰。链路系统传输信号随传输距离成指数衰减,与聚合物光纤的光强衰减规律一致。用商用的发射接收器测得传输距离达到60m以上。聚合物光纤弯曲半径为25mm时,给系统接收端接收信号强度带来0.1~0.4dB的衰减,表明聚合物光纤弯曲对链路系统工作影响较小。