A filter array based on the variable period grating array and Fabry-Perot resonator

Abstract

An integration method of grating array with different periods and Fabry-Perot (FP) resonator with an all-dielectric singlecavity is proposed. It is based on the capacity of spatial separation of spectral component by the grating and band-pass characteristics of filter to achieve the multi-pass band filtering. The filtering response can be tuned by changing the period of the grating rather than the cavity length of the filter. Theoretically, the relationship of the grating period and the peak wavelength is obtained by using the transfer matrix method (TMM). The device is analyzed by adopting the finite-difference time-domain (FDTD) method. The filter array can cover the wavelengths ranging from 850 nm to 950 nm with the full-width at half-maximum (FWHM) of 11–28 nm, and is suitable for the integration of the micro-filter array and the detectors.