Gratings as important spectral components have been employed in various optics applications, such as spectral analysis,
filtering, dispersion compensation, sensing and so on. However, the physical structure of gratings produced by
conventional technologies can not be alterable, this limits their applications under some specific requirements.
Fortunately, MEMS technology breaks through that restriction, an interdigitated comb structure has been demonstrated
in this paper. The comb structure has two sets of comb gratings; one is stationary and the other is movable in the
horizontal plane. By driving the movable comb gratings, the intensity of diffraction will be adjustable. Under the
condition of Fraunhofer approximation, the broadening extent of zero-order diffraction is monotonically increasing with
the longitudinal displacement, and the relation between the intensity of first-order diffraction and the lateral displacement
is a cosine squared function. A displacement sensor based on movable comb structures is presented and detailed analysis
on sensitivity factors is given.