Theoretical and experimental investigation of straight defect waveguides in AlGaAs-based air-bridge-type two-dimensional photonic crystal slabs

Abstract

A detailed investigation was undertaken from both theoretical and experimental perspectives of straight defect waveguides in an AlGaAs-based air-bridge-type two-dimensional photonic crystal slab. Optical propagation properties were obtained by two methods: measurement of transmission spectra at wavelengths ranging from 850 to 1100 nm, and with plan-view observations of the optical beam trace along the waveguide measured with an infrared-vidicon camera. Three-dimensional finite-difference time-domain simulations for the band structure and transmission spectra in the air-bridge slab with and without defect waveguides resulted in the appearance of defect propagation modes specific to the defect waveguide, between two slab modes for the defect-free photonic crystal slab. These defect modes were experimentally identified in the measured transmission spectra.