The B-PHOT nonlinear photonics team investigates the nonlinear-optical physics in emerging 2D and 3D nonlinear materials and employs the nonlinear phenomena to develop next-generation light sources and wavelength converters. Drawing on our theoretical and experimental skills, we model, design and experimentally characterize various types of nonlinear-optical waveguiding structures. Our theoretical work focuses on introducing new ideas and mathematical models for, amongst others, wavelength conversion in diamond-based ring waveguides and spectral broadening of light pulses in graphene-covered waveguides. After the chip fabrication, we perform the targeted proof-of-concept demonstrations using the state-of-the-art equipment available at the B-PHOT labs. The overall goal of our team is to perform groundbreaking research by revealing the physics underpinning complex nonlinear-optical interactions and by enhancing the overall performance of nonlinear photonic integrated circuits.
Over the years the B-PHOT nonlinear photonics team introduced several new concepts to enhance the performance of waveguide devices establishing wavelength conversion. These concepts include, amongst others, intrinsic heat mitigation in Raman lasers and converters using phonon annihilation induced by Coherent Anti-Stokes Raman Scattering (CARS), and automatic quasi-phase-matching of four-wave mixing (FWM) in ring or spiral waveguides without dispersion engineering. The former was numerically demonstrated for silicon-based Raman lasers and converters, whereas the latter was explored for waveguide structures made of silicon and synthetic diamond.
Raman converter with anti-Stokes emission
CARS-induced phonon annihilation
Automatic quasi-phase matching (QPM)
Silicon spiral waveguide designed for QPM
The B-PHOT nonlinear photonics team also investigates nonlinear-optical spectral broadening of light pulses propagating in waveguide structures. To enhance the broadening efficiency, the team works with 2D materials such as graphene and MoS2 deposited on top of the waveguides, yielding extra-ordinary physical phenomena such as counteracting nonlinear responses within the heterogeneous waveguides and quasi-exponentially growing broadening caused by saturable photoexcited carrier refraction (SPCR).