Silicon nitride thermo-optic on-chip Mach-Zehnder interferometer at visible wavelengths

On-chip Mach-Zehnder interferometer (MZI) is a fundamental component for many integrated systems. It holds great promise in photonic applications at visible wavelengths. This paper presents an on-chip silicon nitride thermo-optic MZI. It is capable of generating interference at a wide wavelength range in the visible spectrum, including 488 nm, 532 nm, and 633 nm. The optical transmission loss is reduced by optimizing the device architecture. This work provides new insights into the designing of integrated optics and demonstrates the potential applications of on-chip MZI in the field of visual measurement.