Author: Shuo-Yen Tseng, Department of Photonics, National Cheng Kung University, Tainan, Taiwan
When: July, 3rd - 12PM
Where: Sala de Seminarios
Abstract: Light transfer among waveguides or modes in a waveguide is an important functionality in optical waveguides. In general, mode control relies on resonant mode coupling or adiabatic mode coupling. In mode coupling schemes, control of the modal contents relies on interference of the modes. However, modal interference is sensitive to device geometry and wavelength, leading to tight fabrication tolerance and small bandwidth. On the other hand, adiabatic coupling relies on the slow evolution of the waveguide supermodes. If the adiabatic criterion is satisfied, modal control and manipulation can be achieved with high efficiency, large bandwidth, and high tolerance. However, adiabatic devices need a long evolution length to satisfy the adiabatic condition. Shortcut to adiabaticity (STA), originally developed for quantum control, is a family of protocols that provides a framework to find fast routes to the final results of slow, adiabatic changes of the controlling parameters of a system. Due to analogies between quantum mechanics and wave optics, STA has found many applications in optical waveguides. In this work, we describe various approaches to control modal evolution in waveguide devices by inverse design and adiabaticity engineering, with a focus on silicon photonics devices.
