Shortcuts to adiabaticity in optical waveguides

¹ Department of Photonics, National Cheng Kung University - No. 1 University Rd., Tainan City 701, Taiwan
² Departamento de Química Física, UPV/EHU - Apdo. 644, 48080 Bilbao, Spain
³ Department of Physics, Shanghai University - 200444 Shanghai, PRC

Received: 11 June 2019
Accepted: 27 August 2019

Abstract

In recent years, the concept of shortcuts to adiabaticity (STA), originally developed for speeding up slow adiabatic state evolution in quantum systems, has found numerous applications in guided-wave optics. Optical waveguides, enabled by the advanced fabrication technologies, provide an ideal platform to implement the STA protocols in terms of geometry variations; moreoever, STA has enabled the development of short and robust waveguide components, with applications in beam couplers, beam splitters, mode converters, mode (de)multiplexers, and polarization manipulation devices. Concepts such as counterdiabatic driving, invariant-based inverse engineering, fast-forward approach, or fast quasiadiabatic dynamics, have been shown to provide shortcuts to adiabatic mode evolution in optical waveguides, resulting in compact functional devices with large bandwidth and fabrication tolerance. Novel devices have recently been fabricated following years of theoretical efforts, showing that STA have emerged as a new paradigm in optical waveguides. In this work, we discuss the major STA protocols for applications in optical waveguides and illustrate the shortcuts with device examples.