Medellín - Ciencias - Maestría en Ciencias - Física · 2025
Study of nonlinear optical phenomena in integrated platforms for Near-Infrared and Mid-Infrared
This thesis presents the linear and nonlinear characterization of photonic platforms operating in the near infrared (NIR) and extending toward the mid-infrared (MIR), with emphasis on Si3N4-on-glass waveguides, chalcogenide- based structures, optical fibers, and microring resonators. A systematic experimental methodology was implemented by combining cutback measurements, resonator analysis, and dispersion-scan techniques to quantify propagation losses, evaluate resonant behavior, and identify nonlinear optical signatures. On the linear side, propagation losses were extracted through cutback measurements performed on spiral waveguides and complemented by the analysis of microring resonators. The measurements yielded propagation losses on the order of several dB/cm in the C-band and quality factors on the order of 104, providing complementary information on the linear performance of the Si3N4-on-glass platform. On the nonlinear side, the Top-hat D-scan technique, originally developed for the characterization of third order nonlinearities in waveguides, was adapted and applied to integrated Si3N4-on-glass circuits. The observed valley-to-peak evolution of the spectral width as a function of the applied dispersion constitutes a phenomenological signature of a positive Kerr nonlinearity. Furthermore, the increase of the peak-to-valley excursion with input power was consistent with the expected growth of the accumulated nonlinear phase, revealing the nonlinear response of the platform under femtosecond excitation. In addition, the spectral response of different optical fibers and chalcogenide-based materials was investigated toward longer wavelengths. These measurements highlight the importance of characterizing not only integrated devices but also the optical components required to extend photonic technologies beyond the conventional telecommunications window. Overall, this work establishes an experimental framework for the linear and nonlinear characterization of emerging photonic platforms across different material systems and spectral regions. The combination of propagation-loss measurements, resonator analysis, nonlinear dispersion scans, and extended-wavelength characterization provides a basis for future studies of nonlinear parameter extraction, dispersion engineering, broadband light generation, and photonic technologies operating toward the MIR