Low-power and high-speed thermo-optic switch using hybrid silica/polymer waveguide structure: design,fabrication and measurement

Response speed and power consumption are improved for a Mach–Zehnder interferometer (MZI) thermo-optic (TO) switch, by using a hybrid silica/polymer waveguide structure and optimizing both the thickness of the silica under cladding and that of the PMMA-GMA upper cladding. Fabrication techniques, including chemical vapor deposition (CVD), spin-coating and wet-etching, are adopted to develop the switch sample. Under 1550?nm wavelength, the driving powers under ON and OFF states are measured to be 0 and 13?mW, respectively, indicating a switching power of 13?mW. The fiber-to-fiber insertion loss under the ON state is 15?dB, the extinction ratio between the ON state and the OFF state is 18.3?dB, and the rise time and fall time are 73.5 and 96.5?µs, respectively. Compared with the TO switches based on Si/SiO₂ or all-polymer waveguide structure, the proposed device possesses both low power consumption and fast response speed, by virtue of the large TO coefficient of the polymer core, thin upper/under claddings and the large thermal conductivity of silica.     

Analysis and design of a rib-like-based slot waveguide for nonlinear silicon nanophotonics

Design of efficient nonlinear optical waveguides is an essential requirement for development of silicon nanophotonics. These waveguides should have a unique capability to play the main role in realization of both passive and active optical devices. A high-performance dielectric rib-like-based slot waveguide is proposed for nonlinear silicon nanophotonics. Its slot region can be filled with Si-nc:SiO₂ which exhibits a high third-order nonlinear effect. Study of numerical results shows that this new slot waveguide has a nonlinear parameter of the same order of magnitude as an equally sized silicon nanophotonics strip-based slot waveguide. The new waveguide can be fabricated easily by etching a slot in the core region of the silicon-on-insulator (SOI)-based rib-like waveguide.     

某电厂220kV站Ⅰ、Ⅱ母PT二次电压长期并列运行原因分析与解决办法

在220kV双母线接线的变电站中,为了提高电压切换回路的可靠性,本文根据某电厂220kV变电站电压并列柜上的一起装置异常现象,充分分析电压切换回路的原理和实现,并从安全的角度对相关回路进行了改进,消除了电压回路存在的隐患.