Mark Sotnikov

Major: Physics 

Mentors: Lucas Wang, Galan Moody 

Investigating Device Variation and Nonlinear Efficiency in InGaP Waveguides

Integrated nonlinear photonics enable a variety of promising applications including quantum communication, optical frequency conversion, and optical amplifiers. In particular high efficiency single photon frequency conversion is essential for scalable quantum information systems. To this end III-V semiconductor-on-insulator waveguides such as indium gallium phosphide (InGaP) show promise for facilitating strong nonlinear optical processes such as wavelength conversion. Waveguides act as wires moving information coded in light rather than electricity. One of the major challenges to integrated nonlinear photonics is the sensitivity to fabrication variation. As a result, unintentional differences between devices can impact overall performance and reproducibility. Over the course of 8 weeks, I investigated how device variations in InGaP impact nonlinear efficiency. I tested a variety of devices for their second harmonic generation (SHG), a baseline defining non-linear process. Converting an input wavelength of 1560nm into an output of 780nm. Wavelength scans on several devices revealed which ones had the most promise. Narrowing the field allowed me to optimize my setup for the highest quality device. The results displayed clear SHG at a high efficiency showing InGaP as a great platform for QPIC. Unfortunately, the many examples of little to no phase matching in devices exposed some of the problems in photonic circuits. Additionally, even when optimizedthe power generated was at times spread out rather than concentrated at a specific  wavelength. Local tuning using heating pads can correct imperfections and help concentrate the power where we want to.