Resonant-Wavelength Tuning of a Pitch-Variable 1-D Photonic Crystal Filter at Telecom Frequencies

We propose pitch-variable guided resonance filters for continuous resonant-wavelength tuning at telecom frequencies. Since the optical response is affected by not only the grating period but also the filling factor, in consideration of these parameters, the filter is designed to be tuned smoothly to a selective wavelength by using comb-drive actuators. The grating with the initial period of 860 nm is fabricated with high accuracy. When the grating is expanded, the resonant wavelength shifts to longer wavelength continuously as expected by the calculation.