Cavity Resonator Integrated Grating Filters: a mesoscale plateform for nonlinear optical devices
Résumé
Cavity Resonator Integrated Grating Filters (CRIGFs) are mesoscopic resonant grating based heterostructures that allow excitation of a confined mode through a grating coupler etched on top of a waveguide. The excited mode is spatially bound by two Distributed Bragg Reflectors (DBR) which confine modes in a Fabry-Perot resonator. They can give rise to high Q-factor resonances that will superimpose on the non-resonant transmission and reflection curves of the structure. In recent years, such devices have been demonstrated at multiple wavelengths, ranging from the near infrared around 850 nm wavelength to the mid infrared around 4.65 µm wavelength through the telecom range near 1.55 µm. They have been used as filters or wavelength selective output coupler to stabilize laser diodes in the NIR or MIR spectral ranges. Recent reported work using nonlinear lithium-niobate thin films as waveguides also show the demonstration of second-harmonic generation in these structures under continuous wave (CW) excitation. We will discuss the physics underlying the CRIGF performances, and present recent theoretical and experimental results on their non-linear optical operation.