  We demonstrate the linear and nonlinear characterization of plasma-enhanced
chemical vapor deposited silicon-rich silicon nitride (SRSN) racetrack ring
resonator for on-chip application within the telecommunication wavelength
range. The SRN waveguide parameters are optimized by employing the refractive
index profile measured by ellipsometry to achieve flat dispersion in the
telecom band. Furthermore, we measure the thermo-optic coefficient (TOC) of the
micro-resonator by analyzing the temperature-dependent transmission spectra and
assessing it to be \(3.2825\) $\times$ \(10^{-5}\) \(^o{} C^{-1}\).
Additionally, we perform power-dependent transmission spectra to investigate
the effect of local heating and nonlinear absorption. The power-dependent
transmission spectra exhibit a blue-shifting of the resonance peak in the
visible and near-IR regions, which indicates the presence of nonlinear losses
in that range. The power-dependent transmission spectra almost remain unchanged
in the telecom band, revealing the absence of nonlinear losses and excellent
thermal stability in that wavelength range. Our experimental results reveal
that the SRSN-based structure can be employed potentially to realize linear and
nonlinear applications in the telecom band.
