聚合物波导电光调制器阵列的研究及其应用

基于衰减全反射结构,提出了一种聚合物电光调制器阵列,该调制器含有多对电极,且多对电极可同时极化并可以独立工作.目前我们已在实验室成功制备了双通道聚合物波导电光调制器,并利用此调制器实现两路视频信号的同时调制.     

实现光强精细调制的共轭聚合物波导电光调制器

提出了一种新型的聚合物波导电光调制器,同时利用了聚合物材料的Pockels效应和Kerr效应,在不增加调制电压的情况下,通过引入直流偏压增加了调制器的调制度,调制深度随着直流偏压的增加而增加。采用峰-峰值9.9V的调制电压、100V的直流偏压,利用pockels电光系数γ33仅为4.052×10-14 m/V和二次电光系数S33为6.889×10-21 m2/V2的聚合物材料制备了波导电光调制器,实现了7.54%的调制度。如果采用具有更高的分子极化率及电光系数的非线性共轭聚合物材料,可期待在更低的直流偏压和工作电压情况下,得到更高的调制深度。调制器的工作面积大,可以实现大面积光斑的调制。本文的聚合物波导电光调制器适用于激光脉冲喷丸强化与成形技术,通过调整调制器的直流工作偏压,能够实现激光光斑能量的精细调节。     

光纤聚合物电光调制器电极对波导特性的影响

有机聚合物高速电光调制器是全光纤器件,插入损耗低,集成度高,能极大地降低模式失配和调制电压,提高调制效率,是未来超长距离超大容量高速光通信系统中的关键器件之一。将一种基于长周期光纤光栅的光纤聚合物电光调制器看作5层均匀圆光波导,考虑两层电极及其复折射率的实际情况,利用紧致的超格子方法,在复数域分析这种光纤聚合物电光调制器的波导特性。从模式折射率的实部和虚部、模场分布等角度对数值计算结果进行分析表明,只忽略外电极对调制器的波导特性影响很小,考虑电极时长周期光栅的谐振波长比不考虑电极时大,从而影响调制特性。     

基于自由空间耦合技术的多通道电光调制器的实验研究

研究了一种基于自由空间耦合技术的多通道电光调制器。该集成电光器件是利用双面金属包覆波导激发的超高阶导模对电光材料折射率的高灵敏特性来实现电光调制的。该集成器件具有插入损耗小、响应速度快、稳定性好、制备工艺简单和成本低廉等优点。与传统的棱镜耦合方式的集成电光调制器相比,由于采用了直接耦合方式使器件结构更加紧凑,可更方便的实现器件大规模集成。     

全光纤聚合物电光调制器

设计了一种新型的基于长周期光纤光栅的全光纤聚合物高速电光调制器。应用多层光波导和耦合模理论,分析了这种调制器中长周期光栅的谐振波长随施加在聚合物上调制电压的变化。得出在电压仅为8V时对长周期光栅谐振波长的调制就可达到20nm。     

基于电光聚合物材料的光圆偏振调制器的研制

设计并研制了基于电光聚合物光波导的光圆偏振调制器(CPM)。所研制器件的TE TM偏振模式均衡器部分能够实现TE模与TM模间90%的偏振转换效率,这为器件输出光波的偏振分量均衡提供了相当大的调节范围。在均衡了波导中TE模与TM模的基础上,实验表明,器件的TE TM相位差调制器部分实现了很好的光波圆偏振调制输出特性。所测得的输出线偏振光中,45°与-45°斜角方向偏振分量的消光比大于25dB。基于接触式电极化法所获得的电光特性,TE TM偏振模式均衡器部分的偏振转换周期电压约为230V,TE TM相位差调制器部分的调制特性曲线周期约为192V。     

电光聚合物波导的设计制作及其在光集成中的应用探索

相对于无机材料和半导体而言,极化电光聚合物具有无法比拟的优点响应速度快、介电常数低、调制带宽大、透光波段宽、制备简单、易于集成、成本低廉等.基于电光聚合物的波导器件因其在全光网中的关键作用而越来越引起人们的重视.本文从分析电光聚合物的特性开始,讨论利用高电光系数的聚合物材料设计和制作电光聚合物波导及在工艺中应注意的一些关键问题,介绍了电光聚合物波导器件的应用,其性能和成本优势使其在全光网中具有广阔的应用前景.     

用数值分析方法设计波导电光调制器

本文描述了波导电光调制器傅里叶级数数值分析设计的新方法，利用计算机对波导电光调制器进行傅里叶级数数值计算，得到波导电光调制器的电级的电场分布、器件的特性阻抗和有效介电常数，在此基础上设计出带宽可达７．４ＧＨｚ／ｃｍ和特性阻抗秋５０Ω的波导电光调制器。     

Mach-Zehnder型有机极化聚合物电光调制器

制备了一种以三层聚合物为波导材料的 Mach- Zehnder型电光调制器 ,其中芯层为新型可交联极化聚胺脂电光功能材料 .主要制备工艺为 :旋涂制备波导薄膜、电晕极化、光刻和氧反应离子刻蚀 .以 1.3μm和 1.5 5μm半导体激光器为光源 ,以光纤耦合输入脊波导调制器 ,从输出端得到很好单模近场图 ,其中从 Y型两分支波导输出的光强基本相同 .同时在示波器中得到清晰的调制信号 .     

Mach-Zehnder型有机极化聚合物电光调制器

制备了一种以三层聚合物为波导材料的Mach-Zehnder型电光调制器,其中芯层为新型可交联极化聚胺脂电光功能材料．主要制备工艺为：旋涂制备波导薄膜、电晕极化、光刻和氧反应离子刻蚀．以1.3μm和1.55μm半导体激光器为光源,以光纤耦合输入脊波导调制器,从输出端得到很好单模近场图,其中从Y型两分支波导输出的光强基本相同．同时在示波器中得到清晰的调制信号．     

Electro-optic polymer-based modulator design and performance for 40 Gb/s system applications

We investigate the potential performance of polymer-based electro-optic (EO) modulators for high-speed systems at 40 Gb/s and beyond. General strategies and specific designs are presented to reduce the modulator half-wave drive voltage while maintaining a broadband response. In addition, we consider practical system requirements that may allow the relaxation of certain modulator design parameters to further improve performance. Designs are presented that may enable a 3-dB electrical bandwidth of 30 GHz with a single-ended half-wave drive voltage of /spl sim/1.6 V for 1.3-/spl mu/m light assuming an effective EO coefficient of 30 pm/V in the waveguide core.     

高速铌酸锂电光调制器研究进展

薄膜铌酸锂调制器因其小尺寸、高带宽、低半波电压等优点,成为近年来业内关注的热点。文章梳理了铌酸锂电光调制器的波导结构、电极结构及偏置点控制技术三个方面的相关研究进展,分析了平面掩埋、脊型、光子晶体等三种不同结构波导的调制器性能,讨论了铌酸锂调制器集总和行波两种电极结构的特点及其设计考量因素,对比了电光调制器偏置点控制中功率法和导频法的优缺点及其相关研究成果。在此基础上,进一步分析了为实现更小体积与更高带宽铌酸锂调制器所需的关键技术以及未来的研究方向。     

A mechanically biased electrooptic polymer modulator

Mechanical biasing of an electrooptic polymer modulator is proposed and demonstrated by heterogeneously integrating waveguide structures with a piezoelectric element. Biasing is achieved by changing the path-length of one arms of a Mach-Zehnder interferometer by mechanically bending the waveguide structure. Applying ac voltage to the piezoelectric element generates a pilot tone, which is used to monitor the bias point of the modulator, while applying dc tunes the modulator to quadrature. The method separates the biasing and RF modulation of the device, thus avoiding the need for external biasing components and eliminating electrical bias drift     

基于狭缝波导的聚合物基微环折射率传感器研究

基于狭缝波导结构,设计了工作波长在890 nm的聚合物基微环。从折射率传感的角度详细分析了狭缝波导的模场特性。分析了波导高度、宽度及狭缝宽度对灵敏度的影响。传统的狭缝波导具有较高的弯曲损耗,这会影响微环谐振器的品质因子Q以及消光比。设计了非对称的狭缝结构,保证波导模式位于波导中央传输,降低弯曲损耗。为了条形波导与狭缝波导更好的耦合,设计了基于多模干涉结构的条形-狭缝波导模式转换器。仿真表明设计的微环谐振器的传感灵敏度达到109 nm/RIU。     

Low-loss electrooptic BaTiO/sub 3/ thin film waveguide modulator

A strip-loaded electrooptic waveguide modulator based on an epitaxial BaTiO/sub 3/ thin film was fabricated and characterized for the first time. The strip-loaded waveguide structure greatly improves waveguide propagation and polarization-dependent loss performance. A propagation loss of 1.1 dB/cm and polarization dependent loss of 0.1 dB/cm were measured. The electrooptic waveguide modulator exhibited a half-wave voltage-interaction length product of 4.5 V /spl middot/ cm at a wavelength of 1542 nm. The measured effective electrooptic coefficient of the as-grown BaTiO/sub 3/ waveguide modulator was 38 pm/V. The experimental results indicate that a strip-loaded thin film waveguide modulator is suitable for photonic applications.     

Optical circular-polarization modulator employing tilt-poled electrooptic polymers

A polymer-based integrated circular-polarization modulator (CPM) is demonstrated in this paper. Tilted poling is adopted to achieve polarization conversion in the electrooptic (EO) polymeric waveguide and then realize the power balance between transverse electric and transverse magnetic modes. Detailed analysis and experiments on polarization conversion are presented. The tensor nature of poled polymeric materials is used to generate the phase difference. Contact poling is applied to perform tilted poling and activate the EO effect of polymeric materials. With appropriate voltage control, the polarization state of the output from the CPM can alternate between the left and right-hand-circular states. The extinction ratios at the 45/spl deg/- and -45/spl deg/-tilted linearly polarized states are larger than 25 dB.     

Electrooptic Bragg-diffraction modulators in GaAs/AlGaAsheterostructure waveguides

Reports theoretical and experimental results on electrooptic Bragg-diffraction modulators in GaAs/GaAlAs heterostructure waveguides. The devices utilize the linear electrooptic effect in periodic structures to facilitate spatial modulation of the refractive index in the waveguide. A numerical method was established to solve the waveguide equation and quantify the induced changes in the effective index of the waveguide as a result of reverse bias. The numerical calculation has established the guidelines for an optimum design of the modulator that operates in the Bragg regime. The measured diffraction efficiency of the single-grating Bragg modulator was as high as 90 percent at a driving voltage of 15 V. A device consisting of four such basic diffraction gratings was also fabricated and used to demonstrate the function of scalar addition. The highest bandwidth of the devices that have been measured exceeds 1 GHz. The planar waveguide Bragg modulators offer advantages including lower optical propagation loss, greater fabrication tolerance, and spatial separation between the diffracted and the undiffracted light beams     

The transverse electrooptic modulator (TEOM): fabrication,properties, and applications in the assessment of waveguide electroopticcharacteristics

The fabrication of a novel electrooptic modulator with a transverse electrode geometry, formed by parallel electrodes on opposite faces of a thinned lithium niobate substrate straddling a strip waveguide, is reported. The device, referred to as a transverse electrooptic modulator (TEOM), has several advantages over standard electrooptic waveguide modulators using a coplanar electrode geometry. It is shown that it is possible to achieve a 30% reduction in the operating voltage for a given electrode spacing and a substantial reduction in the figure of merit, the power required per unit bandwidth, for electrooptic modulators with either lumped or traveling wave electrode structures. Moreover, a more accurate estimate of the electrooptic coefficients is possible than with modulators using strip waveguides and coplanar electrodes     

0-1 GHz waveguide 10.6 μm GaAs electrooptic modulator

A GaAs electrooptic modulator for use in 10.6-μm laser frequency shifting applications is described. High-beam-quality output signals with a frequency tunability of 0.1-1.0 GHz were demonstrated. Thick epitaxial GaAs-AlGaAs waveguide structures were successfully fabricated into single-mode channel waveguides with excellent optical and electrooptic properties. A lumped-element modulator, with electrical and electrooptic characteristics in good agreement with theory, was operated at RF drive power levels up to the reverse breakdown voltage limit. The insertion loss of the modulator was quite high, due to absorption losses in the epitaxial material     

Design of a Silicon Based High Speed Plasmonic Modulator

In this paper, we propose a silicon-based high-speed plasmonic modulator. The modulator has a double-layer structure with a 16 μm long metal-dielectric-metal plasmonic waveguide at the upper layer and two silicon single-mode waveguides at the bottom layer. The upper-layer plasmonic waveguide acts as a phase shifter and has a dielectric slot that is 30 nm wide. Two taper structures that have gradually varied widths are introduced at the bottom layer to convert the photonic mode into plasmonic-slot mode with improved coupling efficiency. For a modulator with two 1 μm-long mode couplers, simulation shows that there is an insertion loss of less than 11 dB and a half-wave voltage of 3.65 V. The modulation bandwidth of the proposed modulator can be more than 100 GHz without the carrier effect being a limiting factor in silicon. The fabrication process is also discussed, and the proposed design is shown to be feasible with a hybrid of CMOS and polymer technology.