Spectral tuning of a three-dimensional photonic-bandgap waveguide signature by silica atomic-layer deposition

Recent progress in three-dimensional sub-micron fabrication has rendered the introduction of waveguide structures into optical three-dimensional photonic bandgap materials possible. However, spectral tuning of the waveguide modes has not been demonstrated so far. Here, we use atomic-layer deposition of amorphous silica to tune the spectral position of an air-core defect waveguide in a three-dimensional silicon woodpile photonic crystal by 225 nm in wavelength. The measured spectral positions of the waveguide signature are in very good agreement with numerical calculations.