Towards nano-waveguides

We propose a hybrid type of photonic crystal waveguide (PCW) structure, in which two-dimensional (2D) PCW is embedded in a two one-dimensional (1D) PCW. This rather new PCW structure should be identical to a full three-dimensional PCW in its functionality, but its fabrication is much simpler. Toward the realization of such an amenable PCW structure, an epitaxially grown GaAs/AlAs multilayer structure was successfully converted to an omnidirectional reflector, suitable for the 1D photonic crystal structure in the hybrid PCW. In terms of fabricating 2D-PCWs, we took a rather new approach instead of conventional electron-beam lithography. An air-bridge type of thin film Si 2D-PCW was fabricated using a combined technique of holography and photolithography. Optical characterizations revealed that the propagation loss of the waveguide fabricated such is comparable to those of e-beam generating PCWs in the literature.