This paper proposed a novel broadband filter
using multi-layer sub-wavelength high-contrast grating
(HCG) structure. This filter has wide bandwidth and good
sideband suppression. We simulated and analyzed the
effects of different numbers of layers and different grating
indexes on filtering performance of the broadband filter.
According to the simulated results, we designed a multi-
layer HCG broadband filter, which has bandwidth of 843
nm and center wavelength of 1550 nm.

• Broadband filter using multi-layer sub-wavelength high-contrast grating structure