Design and fabrication of optical filters with very large stopband (≈500 nm) and small passband (1 nm) in silicon-on-insulator

► Modeling with a genetic algorithm (GA) was used to investigate the effect of changing the number of periods and thickness ratios of a photonic crystal filter structure. ► We used the determined optimum parameters at a wavelength of 1550 nm to fabricate the structure. ► Experimental results show that the structure indeed has a very narrow transmission window and a low loss of just 4 dB.