A strain-introduced Mach-Zehnder interferometer (MZI) interleaver on lithium niobate (LiNbO3 ) is proposed. The structure of the strain-introduced waveguide is designed in detail, and is produced by depositing a SiO2 film on the annealed proton-exchanged LiNbO3 waveguide. Considering the sensitivities of the edge strain to the deposition temperature and the thickness of the SiO2 film, an optimum design of 50 GHz interleaver on this structure is given through analyzing the effective index changes for E x pq mode by finite difference method (FDM). The length of the bending waveguide in this interleaver is just two thirds of that in the conventional interleaver due to the high refractive index difference.
For an integrated electro-optical sensor, the operating point has a significant effect on the performance of the sensor. In this paper, an optical waveguide electric field sensor with controllable operating point is designed using LiNbO3 materials, which has an asymmetric Mach-Zehnder interferometer (MZI) structure. Theoretical results show that the optimal operating point can be obtained and controlled by tuning the output wavelength of the tunable laser used in the sensing system. The simulation results show that the sensitivity about 83 dB·μV/m can be obtained, and the linear dynamic range as large as 60 dB can be achieved. And the fabrication tolerance of the center-to-center distance for the 3 dB coupler used in the asymmetric MZI is ~0.5 μm, while the power splitting ratio of the Y branch is with more tolerance.
