Affiliation:
1. Beijing University of Posts and Telecommunications
Abstract
The accurate determination of the effective and group refractive indices (neff and ng) of optical waveguides as a function of wavelength is of critical importance to the design of photonic integrated circuits (PICs). This paper demonstrates the extraction of the two parameters of silicon-on-insulator (SOI) rib waveguides using the transmission spectra of two racetrack micro-ring resonators (MRRs) with different perimeters. The extracted neff and ng exhibit an uncertainty of approximately 10−3. Based on the extracted neff(λ), we estimate the cross-sectional dimension of the SOI rib waveguide that constitutes the MRR. This waveguide has a nominal rectangular cross section with a width, height, and slab thickness of 450 nm, 200 nm, and 70 nm, respectively. The estimated cross-sectional dimension is in accordance with the findings of the scanning transmission electron microscopy (STEM) analysis, exhibiting a discrepancy of approximately 1%. The proposed methodology offers a universal approach to neff and ng extraction and a non-invasive method for cross-sectional dimension assessment, which can be applied in different PIC platforms.
Funder
National Natural Science Foundation of China
State Key Laboratory of Information Photonics and Optical Communications
Beijing University of Posts and Telecommunications