Broadband Microelectromechanical Systems‐Based Silicon Nitride Photonic Switch

Abstract

Over the past three decades, silicon photonic devices have been core to the realization of large‐scale photonic‐integrated circuits. However, silicon nitride is another key complementary metal oxide semiconductor‐compatible material for high‐density photonic‐integrated circuits, having low manufacturing costs, low optical losses, and excellent mechanical properties, that can provide enhanced performance over silicon in an integrated photonic platform. This article presents the design, fabrication, and testing of a proof‐of‐concept switchable silicon nitride photonic coupler that leverages these properties combined with microelectromechanical systems actuation. The photonic platform uses a moveable suspended waveguide to enable efficient out‐of‐plane switching and is built using conventional lithographic techniques to demonstrate the high compatibility with existing microelectronic fabrication techniques. The photonic switch is measured to have an insertion loss of 2.6 dB and an ON/OFF extinction ratio of 34 dB at the output of the suspended waveguide, at a wavelength of 1470 nm. Detailed simulations demonstrate broadband operation over a 600 nm wavelength range from 1.25 to 1.85 μm which is experimentally validated over the range from 1.25 to 1.61 μm. To the best of knowledge, this is the broadest operation range ever demonstrated by a photonic switch in simulation.