Low-dispersion low free-spectral-range Mach-Zehnder interferometer with long straight path lengths on silicon

TL;DR

This paper demonstrates a silicon Mach-Zehnder interferometer with long straight paths that reduces dispersion and achieves a free spectral range of 0.41 nm, improving spectral performance for integrated photonics.

Contribution

It introduces a novel design of silicon Mach-Zehnder interferometers with extended straight waveguide sections to mitigate dispersion and enhance free spectral range.

Findings

Achieved a free spectral range of 0.41 nm.

Long straight waveguides reduce dispersion effects.

Variation in waveguide length affects transmission spectrum.

Abstract

Multiple Mach-Zehnder interferometers are constructed using fiber-Bragg grating couplers, y-branches, silicon waveguides, and/or broadband splitters in silicon on insulator strip waveguides to test the effect of variation in waveguide length between consecutive bends on the transmission gain spectrum, free-spectral range, group refractive index, and dispersion. Dispersion is mitigated by increasing the path length between consecutive bends of minimum radius. With long linear waveguide sections, a free spectral range of 0.41 nm is achieved.