Y-branch defect waveguides (DWGs) in an AlGaAs-based air-bridge-type two-dimensional (2D) photonic crystal (PC) slab were fabricated, and the resulting optical transmission spectra were measured. Optical beam propagation along the waveguide was successfully observed in vidicon IR images. The measured transmission spectra at the two output ports in the Y-branch DWG were remarkably similar in shape and magnitude. From comparison between the measured and calculated transmission spectra, the observed optical beam was identified as the guided mode based on the Y-branch DWG in the 2D PC slab. The results suggest that the Y-branch DWG used in the experiment has the potential to function as an ultrasmall 3-dB beam splitter with good performance.
© 2002 Optical Society of America
Y. Sugimoto, N. Ikeda, N. Carlsson, K. Asakawa, N. Kawai, and K. Inoue, "Light-propagation characteristics of Y-branch defect waveguides in AlGaAs-based air-bridge-type two-dimensional photonic crystal slabs," Opt. Lett. 27, 388-390 (2002)