Low-loss, single-mode, organic polymer waveguides utilizingrefractive index tailoring

Low-loss, single-mode optical waveguides have been fabricated from photopolymerizable acrylic monomers. The material system consists of a low-index cladding resin and a high-index core resin. The two resins are miscible so that precise control over the refractive index can be obtained. This allows the fabrication of single-mode waveguides with specific cross-sectional dimensions. One advantage of this is the ability to fabricate waveguides with high coupling efficiencies to other devices such as optical fiber or semiconductor lasers. The materials adhere to a wide variety of substrates and exhibit average waveguide losses of 0.56 dB/cm at 1300 nm for single-mode waveguides. Details of the fabrication procedure, index of refraction tailoring technique, and waveguide loss data are presented     

Sol-gel glass waveguide and grating on silicon

This paper reports on the fabrication and characterization of hybrid organic-inorganic glass sol-gel slab and channel waveguides by ultraviolet light imprinting in thin films deposited by a one-step dip-coating process. The adjustment of chemical composition of the materials provides precise selection of refractive index from 1.48 to 1.52 at the wavelength of 632.8 mn. The refractive index of the waveguides at 1.55 μm is similar to that of optical fiber, thus reducing the reflection loss between the two to less than 0.01 dB. The effect of ultraviolet light exposure and heat treatment on waveguide refractive index is studied. Fabrication parameters to produce ridge waveguides are optimized to achieve very smooth side walls. Propagation losses in these waveguides are ~0.1 dB/cm. Single mode buried waveguides, at 1.55 μm wavelength, with circular mode profile are demonstrated     

Polymer Optical Interconnects—A Scalable Large-Area Panel Processing Approach

A flexible approach to producing optical interconnects on 609.6$ast ,$609.6 mm large-area panels is demonstrated. Stepwise projection patterning from 101.6$ast ,$101.6 mm masks has generated optical waveguide patterns over the whole panel using large-area projection lithography equipment. The waveguide routing design allows optical waveguides on different 101.6$ast ,$101.6 mm tiles to be interconnected. Four different waveguide connecting geometries in the border region between tiles have been fabricated and tested. Multimode waveguides from inorganic-organic hybrid polymers (ORMOCER) (cross section:$le hbox 50~muhbox mast hbox 10~muhbox m$) with refractive index step between core and cladding$Delta n=hbox 0.01$were produced. The index step was adjusted by mixing two diffrent ORMOCER systems. The materials show good adhesion to numerous substrates, such as glass and silicon. Application concepts such as flexible manufacturing of optoelectrical hybrid backplanes with two-dimensional interconnect, a three-dimensional optical interconnect with optical vias, and a hybrid backplane with the optical interconnect in a strip-format on a separate plane right above the electrical plane are proposed. Promising new technologies are presented along with preliminary demonstrativ viability.     

Integration of magnetooptical waveguides onto a III-V semiconductorsurface

Optical waveguides fabricated on a yttrium iron garnet (YIG) substrate are integrated onto a semiconductor surface by using ridge waveguides patterned onto a prefabricated recess in the YIG surface. The recess separates the waveguides from the semiconductor substrate with an air-gap. This structure makes it possible to avoid coupling light within the YIG waveguides into the semiconductor substrate which has a higher refractive index. The excess optical loss due to the coupling can be as low as ⩽0.1 dB/cm with a 1-μm-wide air-gap. The calculated coupling loss is confirmed by comparing the guided TE and TM modes     

Glass waveguides on silicon for hybrid optical packaging

Work on deposited glass waveguides on silicon to form waveguides and filters is reviewed. The choice of these particular waveguides makes sense only as part of a consistent approach to optoelectronic packaging. Hybrid optical packaging on silicon (HOPS) is described and briefly compared with other techniques. For these packages, two waveguides were developed: a tight mode waveguide with a silicon nitride rib core for matching a semiconductor laser and a loose mode waveguide with a phosphosilicate glass core for matching an optical fiber     

两步离子交换低损耗光波导功分器的研制

报道了在热扩散条件下两步离子交换玻璃光波导功分器的理论分析、样品制作和实验测试.为了便于定量分析,采用了一种上升反正弦S型分支光波导系统的物理模型,得到了在热扩散条件下两步离子交换光功分器波导区的归一化折射率分布和在不同交换时间所形成的玻璃波导折射率分布.在此基础上,设计和制作出第一步采用含Tl 纯熔盐Tl2SO4与玻璃含Na 进行离子交换形成表面下半圆形波导,再把该波导表面脱钛膜放入含Na 熔盐NaNO3中进行第二步离子交换形成掩埋式圆形波导光功分器,实现插入损耗为0.15 dB和分光比为50:50的上升反正弦S型玻璃光波导功分器.     

电场辅助离子交换制备玻璃光波导

使用电场辅助离子交换和热离子交换技术在玻璃基片上制作了平板波导。实验结果表明,这两种方法制作的波导的有效折射率分布不同,电场辅助离子交换技术制作的波导有效折射率呈近似阶跃型分布,而热离子交换制作的波导有效折射率分布为渐变型。经数值计算发现,近似阶跃型折射率分布的波导对光场限制得更好,更适用于制作有源光器件和集成光器件。     

Improved coupling efficiency using Δn-controlled polymerwaveguides with two-dimensional spot-size transformation

A new type of polymer waveguide for two-dimensional spot-size transformation is reported, with which coupling efficiency of waveguides with 4- and 8-μm core diameters was reduced by ≈1.6 dB. The length needed for spot-size transformation was less than 1 mm along the direction of propagation. In this polymer waveguide, refractive index difference between core and cladding (Δn) is properly controlled along the direction of propagation while the core cross section is kept uniform     

Characterization of refractive index profiles in silver-sodiumion-exchanged glass waveguides for homogeneous refracting waveguidestructures

The refractive index profiles are investigated for Ag⁺-Na⁺ ion-exchanged waveguides in soda-lime glass. The waveguides with the highest index change, used to design homogeneous refracting waveguide lenses and prisms, are fabricated at 350°C using concentrated melt with composition of 10 mol.% AgNO₃ and 90 mol.% NaNO₃. The profiles of two- and three-mode waveguides are reconstructed from the measured mode refractive indexes. The linear correlation between the index change and the silver concentration in glass is experimentally confirmed. The concentration profiles are numerically simulated on the base of diffusion-exchange theory. It is established that the values of the maximum in index profile near the glass surface tend to a saturation value after a long exchange time     

Optical study of porous silicon buried waveguides fabricated from p-type silicon

The realisation of optical buried waveguides fabricated from porous silicon layers is presented. The refractive index of porous silicon layer varies according to its porosity and its oxidisation process conditions. So either step or graded index waveguides are achieved. These waveguides are formed by a localised anodisation of heavily doped p-type silicon wafers. Measurements at a wavelength of 1.3 μm yield waveguide losses below 4 dB/cm. The waveguides are also characterised by the near-field-guided mode profile at 1.3 μm. This study deals with the modulation of the waveguiding-layer refractive index and the losses on waveguides fabricated from p⁺.     

离子交换平板玻璃光波导

本文报导了把玻璃放在熔融的AgNO_3中制备玻璃光波导,其工艺简单,可以重复.我们测量了波导的有效折射率、波导厚度以及损耗等.波导损耗小于1分贝/厘米.     

紫外写入技术制备光波导器件研究

研究了采用PECVD方法生长的Si基SiO2波导材料的光敏特性.经过高压载氢处理,利用KrF准分子激光脉冲(工作波长为248nm)在波导材料中诱导出的折射率变化量达到0.005,相对值约增加0.34%.详细研究了紫外光诱导出的折射率变化沿样品深度方向的分布情况.最后,采用紫外写入法在PECVD方法生长的Si基SiO2波导芯层中制备出了单模波导和Y分束器样品,并观测到了通光现象,实测结果与模拟结果一致.     

退火质子交换LiNbO3光波导低损耗耦合分析

利用光束传播法分析了退火质子交换铌酸锂光波导模场参数随波导宽度、深度和表面折射率改变的变化情况,指出波导模场受这些参数的综合影响,并讨论了波导结构参数对光纤．波导耦合效率的影响。结果表明,要实现最佳耦合,不同模场直径的光纤对波导结构参数的要求是不同的,这可供相应波导器件的设计和制备参考。     

Fabrication and Characterization of Benzocyclobutene Optical Waveguides by UV Pulsed-Laser Illumination

Buried-type benzocyclobutene (BCB) optical waveguides fabricated by UV pulsed-laser illumination are proposed and comprehensively characterized in this paper. The fabrication process is greatly simplified as compared to conventional dry-etched ridge-type BCB waveguides. The measured propagation loss at 1548 nm is as low as 0.6 dB/cm due to the buried waveguide structure. And the produced refractive index change is dependent upon the number of laser shots such that single-mode waveguides with different mode sizes can be tailored for efficient coupling. Furthermore, rigorous analyses of surface damage threshold, rms roughness, and chemical characteristics under different illumination conditions are presented to illustrate the design considerations and the chemical mechanism of the UV-induced BCB waveguides     

溶胶—凝胶法制备PZT薄膜的结构和波导特性

采用溶胶－凝胶方法制备了ＰＺＴ（５０／５０）薄膜，用椭偏仪和透射光谱分别测量并计算了年鉴备在Ｓｉ（１１１）、石英玻璃基片上薄膜的折射率、研究了薄膜的相结构与折射率之间的关系以及折射率和消光系数的色散关系。用棱镜耦合的方法测量了薄膜的波导损耗，并给出了波导损耗与工艺过程的关系。     

紫外写入技术制备光波导器件研究

研究了采用PECVD方法生长的Si基SiO2波导材料的光敏特性.经过高压载氢处理,利用KrF准分子激光脉冲(工作波长为248nm)在波导材料中诱导出的折射率变化量达到0.005,相对值约增加0.34%.详细研究了紫外光诱导出的折射率变化沿样品深度方向的分布情况.最后,采用紫外写入法在PECVD方法生长的Si基SiO2波导芯层中制备出了单模波导和Y分束器样品,并观测到了通光现象,实测结果与模拟结果一致.     

玻璃波导有效折射率的原位测量（特邀）

飞秒激光直写玻璃波导是快速制备三维集成光子芯片的一种重要手段,波导有效折射率的准确测量对于设计光子器件意义重大。设计并制备了一种断臂马赫-曾德尔干涉仪（MZI）结构对玻璃波导有效折射率进行原位精密测量。激光在断线区域和波导内的有效折射率不同,在传输相同长度下产生一定的相位差,最终导致不同的干涉结果。对断臂MZI结构的相位干涉结果进行处理,得到激光直写玻璃波导的有效折射率为1.504+7.7×10?4。利用RSOFT软件光束传播算法对器件进行模拟仿真,仿真结果与实验吻合良好。该精确测量玻璃波导有效折射率的方法对于提升光子芯片设计与制造能力具有重要意义。     

铜离子交换单步掩埋BK7玻璃波导的制备与表征

利用Cu离子交换技术制备了BK7玻璃平面光波导,在6328nm波长下,用棱镜耦合技术测量出所制备波导的有效折射率,利用反WKB方法计算并确定了平面光波导的折射率分布,通过对折射率分布进行函数拟合,发现离子交换后的样品折射率分布近似符合改进后的高斯分布,样品的折射率分布似乎是一个掩埋波导的折射率分布,求出所制备玻璃平面光波导在570℃的扩散系数De≈12133×10-14m2s。同时,对所制备波导进行了电子显微镜(EMS)和次级离子质谱(SIMS)测试,得到了铜离子在玻璃表面的浓度分布,从而证明了实验所得到的BK7玻璃平面光波导是掩埋波导。这种掩埋平面波导是由单步Cu离子交换技术得到的。     

Pumping planar waveguide amplifiers using a coupled waveguidesystem

A novel scheme is presented that can be used to efficiently pump optical waveguide amplifiers. It is based on the coupling between two adjacent waveguides, where pump light is gradually coupled from a nonabsorbing pump waveguide into the amplifier waveguide. The coupling between the waveguides in such a configuration is calculated using an improved coupled mode theory (CMT). The proposed distributed coupling scheme can enhance the optical gain in systems that exhibit a reduced pumping efficiency at high pump power. A numerical example is given for a sensitized neodymium-doped polymer waveguide amplifier, in which the optical gain increases from 0.005 dB to 1.6 dB by changing from conventional butt-coupling to distributed coupling     

缓冲质子源LiNbO3波导折射率计算及实验

为实现铌酸锂退火质子交换(APE)波导折射率分布的准确计算,选择含苯甲酸锂的苯甲酸缓冲液作为质子交换质子源,高温退火制作了波导样本.针对该工艺过程建立退火质子交换波导模型,包括非线性扩散模块和光学数值仿真模块,分别计算APE波导折射率及其模式有效折射率.以测得的样本波导模式有效折射率和计算的有效折射率差的均方根构建评价函数(FOM),结合遗传算法提取该工艺条件下质子扩散参数,实现了不同交换深度和退火时间波导折射率分布及其光学特性的一体化计算.实验表明:FOM小于0.001,计算折射率分布同IWKB方法测得结果吻合较好,最大偏差约0.002.