Photonic crystal with defects such as (L1H1)m LCH2(L2H2)n is investigated in this paper. The band gap edge transmission peak is narrowed when the couple-layer LC and the cover layer H2(L2H2)n are added to the photonic crystal (L1H1)m.
Two different structures were studied in thip paper. Structure A is not suitable for the tunable filter, which has two discrete tuning regions. Structure B provides a good optical tuning method: large dynamic range (>150 nm), narrow bandwidth (FWHM is about 2 nm) and good tuning linearity. This kind of structure can be fabricated by the surface micromachined technique easily.