1-D photonic crystals with defects such as (L1H1)mLCH2(L2H2)n are investigated. The bandgap 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. Three different structures are studied. Structure A is not suitable for the tunable filter, which has two discrete tuning regions. Structures B and C provide good optical tuning methods: large dynamic range (>150 nm), narrow bandwidth [full-width at half maximum (FWHM) is about 2 nm], and good tuning linearity. These structures can be easily fabricated by the surface micromachined technique.