title: Electro-optic mode switch based on lithium-niobate Mach-Zehnder interferometer.
abstract: We propose an electro-optic mode switch based on an optical waveguide Mach-Zehnder interferometer fabricated with x-cut lithium niobate by the annealed proton exchange process. The device can switch between the fundamental mode and the higher-order mode with a low driving voltage. Our typical fabricated device, which has a total length of ∼24  mm, shows a mode extinction ratio of ∼35  dB and a 20-dB bandwidth of ∼12  nm at the wavelength 1552 nm, when driven at a voltage of 1.7 V at 26°C. High performance can be obtained at any wavelength in the C+L band with a driving voltage varying by no more than 3 V. The proposed mode switch is easy to fabricate and could find applications in reconfigurable mode-division-multiplexing systems.
authors.forename: Mengruo
authors.initials: M
authors.lastname: Zhang
authors.forename: Kaixin
authors.initials: K
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Jin
authors.forename: Kin Seng
authors.initials: KS
authors.lastname: Chiang