Realization of monochromatic filter using silicon grating structure: An application of silicon photonics

This paper attempts to discuss the realization of monochromatic filter using silicon monoxide-silicon (SiO-Si) grating structure having defect at 18th and 52nd position. Here both absorption and reflection losses are considered to compute reflectance and transmittance. Simulation is made using plane wave expansion method. Simulation result showed that suitable combination of thickness of odd and even layers of above grating structure plays an important role to obtain reflectance and transmittance. It is also revealed that silicon monoxide-silicon grating structure with defect (air) at 18th and 52nd position behaves as monochromatic filter for thickness of even layer, 80 nm and thickness of odd layer varies from 40 nm to 190 nm. Apart from this, it is also observed that for some combination of thickness (t1,t2) grating layers, such as (50 nm, 80 nm), (60 nm, 80 nm), (70 nm, 80 nm), (80 nm, 80 nm), (90 nm, 80 nm) (110 nm, 80 nm), (120 nm, 80 nm), (130 nm, 80 nm) grating allows single wavelength only, which can be considered as ideal monochromatic filter. Again simulation studies showed that width of the reflected band gradually increases with the increase of grating length.