Ultra-Small Photonic-Crystal-Waveguide-Based Y-Splitters Useful in the Near-Infrared Wavelength Region

We report on the successful development of an ultra-small photonic-crystal(PC)-waveguide-based 120° Y-splitter operating at 1310 nm, which consists of mutually intersecting single-line-defects in the Γ-K direction with an additional air-hole in the middle of the intersection, based on the air-bridge-type GaAs PC of an array of air-holes. The transmittance spectra observed by using a halogen-lamp-based spectrometer newly developed for thin PC-waveguide samples, reveal that a total transmittance of 85% at two output ports is achieved with a band-width as broad as 50 nm. This result indicates that the present Y-splitter should be useful as a key component in future ultraminiature planar optical circuits.