SOI亚微米波导光栅的设计与制作

报道了SOI基亚微米小尺寸波导光栅器件的设计、制作与测试结果。提出了波导与光栅同步制作的方案,避免了套刻,节约了成本。实验中采用电子束光刻(EBL)、感应耦合等离子体(ICP)刻蚀等先进半导体工艺技术,结合图形补偿等技术手段,完成了亚微米波导光栅的制作。光栅周期为350nm,占空比16∶19。采用该光栅做反射镜,制作了法布里-珀罗(F-P)谐振腔,经测试得到了与模拟相吻合的结果,峰谷比达到11dB。     

二维三角晶格空气孔光子晶体直线型波导的TE波传输特性研究

本文利用了时域有限差分法(FDTD)研究了TE波在二维三角晶格空气孔光子晶体线缺陷形成的直线型波导中的传输特性,给出了在TE极化下缺陷的结构参量变化与波导的频带宽度、波导中心频率的变化关系,为制作二维三角晶格空气孔线缺陷形成的波导提供了理论依据.     

Consideration of chiral optical fibres

Circular birefringence is a property of chiral materials. In this work, we consider the use of chiral materials in optical fibres to produce circularly birefringent optical fibres and in fibres where a contrast in circular birefringence contributes to forming the waveguide. (-)-menthyl methacrylate is also investigated as a possible material for the fabrication of such fibres.     

Planar optical waveguides prepared in GIL49 and BK7 glass substrates by K+-Na+ ion exchange with the electric field assistance

This report focuses on research into waveguides prepared by K⁺-Na⁺ ion exchange with the help of an electric field, and the subsequent comparison with waveguides prepared by pure thermal ion exchange. The goals of this work were to determine the characteristics of and to address the technological problems associated with waveguides prepared in two types of highly pure optical glass: special soda-lime silica GIL49 glass produced from pure raw materials and commercially prepared borosilicate BK7 glass. An appropriate chemical mixture, KNO₃:Ca(NO₃)₂ in the molar ratio of 41:59, was used as the source of potassium ions. Experiments were conducted at temperatures between 250 and 410°C, and electric field values between 0 and 150 V/mm. The number of modes, depth, profile, and the change in refractive index (Δn) were measured for samples from each type of glass under various technological conditions. All of these parameters can be controlled accurately and repeatedly by the electric field. These experiments have also shown that a particular advantage of these types of pure glass is the low waveguide optical losses (0.1 to 0.2 dB/cm) attainable.     

Green biomass bistable transistor multivibrator

For the first time a biomass bistable transistor multivibrator using an NPN Philips transistor as the active device and freshly plucked green Champo (Plumaria rubra) leaf cuttings as electrical components (resistance R and capacitance C) has been realized. The frequency and other parameters of the generated pulses, along with the circuit configuration, are presented. The development envisages a novel march towards a green revolution in electronic circuitry.     

Analysis of the propagation losses of InP/InGaAsP trench waveguides fabricated by focused ion beam

Focused ion beam was used to fabricate 2 mm-long, 4 μm-wide and 4 μm-deep multimode trench waveguides in InP/InGaAsP. An automated stitching method was developed to fabricate mm-long structures using alignment marks. The waveguides were sputtered or etched using I₂ at room temperature and 150 °C stage temperature. The propagation losses induced by the different fabrication techniques were measured and ranged between 50 and 82 dB/cm. A damaged layer with implanted Ga and the sidewall roughness are identified to be the most important causes for the losses. FIB is shown to be a single-step fabrication technique for rapid-prototyping of photonic structures in InP/InGaAsP.     

Multimode equivalent network representation for junctions between coaxial and circular waveguides

In this article we present two contributions to the study of coaxial waveguide structures. First, we present an efficient and accurate technique to evaluate the modes in the coaxial waveguides; second, we analyze junctions involving coaxial and circular waveguides using the multimode equivalent network representation. Numerical and experimental results are presented, showing good agreement. © 1997 John Wiley & Sons, Inc. Int J Microwave Millimeter-Wave CAE 7: 180–194, 1997.