Probing the dispersive and spatial properties of planar photonic crystal waveguide modes via highly efficient coupling from optical fiber tapers

摘要

The demonstration of an optical fiber based probe for efficiently excitingthe waveguide modes of high-index contrast planar photonic crystal (PC) slabsis presented. Utilizing the dispersion of the PC, fiber taper waveguides formedfrom standard silica single-mode optical fibers are used to evanescently couplelight into the guided modes of a patterned silicon membrane. A couplingefficiency of approximately 95% is obtained between the fiber taper and a PCwaveguide mode suitably designed for integration with a previously studiedultra-small mode volume high-Q PC resonant cavity [1]. The micron-scale lateralextent and dispersion of the fiber taper is also used as a near-field spatialand spectral probe to study the profile and dispersion of PC waveguide modes.The mode selectivity of this wafer-scale probing technique, together with itshigh efficiency, suggests that it will be useful in future quantum andnon-linear optics experiments employing planar PCs.