A tunable split-ladder photonic crystal cavity by nanoelectromechanical actuator

Abstract

In this paper, we demonstrate a novel split-ladder photonic crystal cavity, which can be tuned across a very large wavelength range by an on-chip integrated nano-electromechanical actuator. The nano-electromechanical actuator is used to control the cavity's central gap. When the cavity gap is widened, the resonance wavelength is blue-shifted correspondingly. The dimensions of the proposed split-ladder cavity are designed by 3D Finite-difference time-domain (FDTD) calculations. We fabricated and tested the devices. Experimental results show that the optomechanical coupling coefficient of the second order resonance mode is about 80 GHz/nm. In addition, there is a relatively linear relationship between the resonance shift and the gap change. The maximum measured resonance wavelength shift is about 17 nm, corresponding to a cavity central gap increase of 26 nm. © 2013 SPIE.