Experimental investigation on the unbalanced Mach–Zehnder interferometer on lithium niobate thin film

Abstract

We design and fabricate an unbalanced Mach-Zehnder interferometer (MZI) via electron beam lithography and inductively coupled plasma etching on lithium niobate thin film. The single unbalanced MZI exhibits a maximum extinction ratio of 32.4 dB and a low extra loss of 1.14 dB at the telecommunication band. Furthermore, tunability of the unbalanced MZI by harnessing the thermo-optic and electro-optic effect is investigated, achieving a linear tuning efficiency of 42.8 pm/C and 55.2 pm/V, respectively. The demonstrated structure has applications for sensing and filtering in photonic integrated circuits.