Lithium Niobate-Based MMI-MZI Electro-Optic Switches with Lower Phase Shift Voltage

Optical switches that effectively isolate outputs are crucial for precisely and efficiently directing and controlling optical signals. This study presents the design and characterization of a 1×2 electro-optic (EO) switch utilizing few-mode waveguides on a lithium niobate on insulator (LNOI) platform. Simulations conducted with the beam propagation method revealed equal splitting between outputs at 0 volts. When 1 volt was applied, the output switched to the bar port of the MMI, and at 3.5 volts, the output switched to the cross port of the MMI at a wavelength of 1.55 μm. The device, measuring 6.56 mm in length, exhibits a voltage efficiency of 1.66 V·cm. The switch shows minimal insertion loss of 1.85 dB for output 1 and 1.87 dB for output 2, ensuring efficient signal transmission. Additionally, it maintains low crosstalk levels of −30 dB and −27.72 dB for output 1 and output 2, respectively, indicating effective isolation between output channels. Received: 8 September 2024 | Revised: 7 November 2024 | Accepted: 7 March 2025 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data are available from the corresponding author upon reasonable request. Author Contribution Statement Md Koushik Alam: Conceptualization, Methodology, Formal analysis, Resources, Data curation, Writing – original draft, Visualization. Noor Afsary: Software, Formal analysis, Writing – original draft. Md Nasir Uddin: Formal analysis, Investigation, Writing – review & editing. A. K. M. Naim Ishtiaq: Formal analysis, Data curation, Writing – review & editing. Md Omar Faruk Rasel: Conceptualization, Writing – review & editing, Supervision.