Seeded Second-Harmonic Generation in Silicon-rich Nitride

Summary:

Demonstrating large second-order nonlinear effects in integrated platforms has been a widely pursued aim. All-optical poling of silicon-nitride (SiN) waveguides is a technique to induce second-order nonlinear nonlinearities. Here, pump and its phase-locked second-harmonic lead to generation of periodic photocurrent satisfying quasi-phase-matching condition leading to a DC field and therefore a second-order susceptibility. While generating photocurrent these fields lead to increase of photoconductivity. This leads to a complex interplay governing the efficiency of these devices. The material constants have been extracted for stochiometric silicon nitride. This project based on all-optical poling of silicon-rich silicon nitride waveguides and at the end of this project the material properties will be extracted and compared with stochiometric silicon nitride.

Main objectives:

• Demonstration of all-optical poling in silicon-rich nitride
• Fitting of optical poling traces to governing equation
• Extraction of phase of photocurrent, photogalvanic coefficient and conductivity
• Finding the limitations of conversion efficiency and comparison with other materials

Supervisor:

• Prof. Camille-Sophie Brès (camille.bres@epfl.ch)