Fabrication and characterization of hollow waveguide optical switch with variable air core.

We demonstrate a novel hollow waveguide optical switch composed of an multi-mode interference (MMI) coupler with a variable air core. The numerical simulation and experiment of the proposed optical switch is carried out for investigating the operation of the switch. Switching operation can be obtained by the mechanical displacement of the air core of an MMI hollow waveguide. A hollow waveguide consists of Au mirrors deposited on two GaAs substrates for optical confinement. The measured result shows a possibility of switching of about 85% optical power fraction with a switch length of 1.1 mm and small displacement (DeltaDcore=3 mum) of an air core thickness. The measured insertion losses of a 1.1 mm long hollow waveguide with 12 and 9 mum air core are 5.4 dB and 5.7 dB, respectively.