Electro-Optically Switchable Optical True Delay Lines of Meter-Scale Lengths Fabricated on Lithium Niobate on Insulator Using Photolithography Assisted Chemo-Mechanical EtchingSupported by the National Key R&D Program of China (Grant No. 2019YFA0705000), the National Natural Science Foundation of China (Grant Nos. 11734009, 61590934, and 11874375), the Strategic Priority Research Program of CAS (Grant No. XDB16030300), and the Key Project of the

Abstract

Optical true delay lines (OTDLs) of low propagation losses, small footprints and high tuning speeds and efficiencies are of critical importance for various photonic applications. Here, we report fabrication of electro-optically switchable OTDLs on lithium niobate on insulator using photolithography assisted chemo-mechanical etching. Our device consists of several low-loss optical waveguides of different lengths which are consecutively connected by electro-optical switches to generate different amounts of time delay. The fabricated OTLDs show an ultra-low propagation loss of ∼ 0.03 dB/cm for waveguide lengths well above 100 cm.