Drop and split filter in a hole-type photonic crystal

A drop and split filter (DSF) based on a self-collimation ring resonator (SCRR) in a hole-type photonic crystal is proposed and demonstrated. The DSF performance was investigated with the finite-difference time-domain (FDTD) simulation technique. By forming three splitters of the SCRR properly, self-collimated light can come out from two drop ports equally while no light come out from the through port. For the drop wavelength of 1550 nm, the free spectral range is 29.7nm, which covers the whole optical communication C-band window. This DSF may have applications in photonic integrated circuits.