Tunable optical, notch filter realized by shifting the photonic bandgap in a silicon photonic crystal line-defect waveguide

A tunable optical notch filter was realized by thermally shifting the TM-like (the light's electric field perpendicular to the substrate) bandgap of a silicon photonic crystal slab W1 line-defect waveguide with silica cladding. This device is compact-its footprint is 340 x 16 mu m(2), excluding the electrode pads. The 3-dB bandwidth of the device was about 5 run, and the extinction ratio at the center wavelength was as high as 40 dB. A maximum center wavelength shift of 17.9 run was attained at a heating power of 0.7 W, with a tuning efficiency of 25.5 mn/W. The tuning response time was less than 100 mu s.