In this thesis, we theoretically model and experimentally characterize resonance responses of prism-coupled square optical micropillar resonator-based wavelength-sensitive filters for optical communications. As compared with integrated waveguide-coupled micropillar resonators, prism-coupled micropillar resonators have the key merit of tunable laser beam incident angles for selective evanescent coupling or refractive coupling with microresonator modes....[ Read more ]

In this thesis, we theoretically model and experimentally characterize resonance responses of prism-coupled square optical micropillar resonator-based wavelength-sensitive filters for optical communications. As compared with integrated waveguide-coupled micropillar resonators, prism-coupled micropillar resonators have the key merit of tunable laser beam incident angles for selective evanescent coupling or refractive coupling with microresonator modes.

We theoretically study the resonance responses such as (i) coupling efficiency, (ii) quality factor, (iii) resonant wavelength, and (iv) resonance lineshape by using two-dimensional Fabry-Perot-like model. We concluded that a microresonator can be critically-coupled with a 100% coupling efficiency when the air-gap thin-film transmitted power into the microresonator equals the microresonator round-trip power loss. This critical-coupling condition is independent to the microresonator shapes or the coupling mechanisms.

In the experiment, we employed angle-resolved prism-coupling technique to study the frustrated total internal reflection (TIR) spectra of a 200-μm-sized silica square micropillar resonator. For TM (TE) polarization, an optimum coupling efficiency of about 94% (exceeding 97%) with quality factor exceeding 13,000 (7,000) was obtained at a far-field angle corresponding to an incident angle just above the TIR critical angle.

We also investigated in the angle-resolved reflected spectra sharp asymmetrical resonance lineshape, known as Fano lineshape, which can be attributed to the interference between a resonance mode and a coherent background. In our experiment, four 2π periods of Fano lineshape evolution were clearly discerned in TM-polarized reflected spectra, while two 2π periods of Fano lineshape evolution were observed in TE-polarized spectra. We constructed a theoretical model based on the interference between a high-Q resonance mode and a coherent background due to TIR at the prism-air interface or other resonance modes. The calculated asymmetrical resonance lineshapes in the reflected spectra find good qualitative agreement with the measured resonance lineshapes.