Optical filter with very large stopband (approximately 300 nm) based on a photonic-crystal vertical-directional...

We have designed, fabricated, and demonstrated a vertical directional coupler based on the coupling between a polymer waveguide and a W1 photonic crystal waveguide. The filters have a bandwidth of approximately 2 nm within a stopband of Delta lambda approximately 300 nm and an on-chip insertion loss of 1 dB. This is the first (to our knowledge) demonstration of a filter with such a large stopband that overcomes the bandwidth limitation of existing filters.