Channel spacing control of microring resonator add/drop filter array by UV trimming technique

Abstract

In the multi-channel microring resonator filter, the wavelength channel spacing was limited to 5.7 nm due to the resolution limit of the photomask (50 nm). Therefore, we developed a new technique to control precisely the channel spacing by a UV-trimming technique using polysilane as the over-cladding layer. As a result, we successfully decreased the channel spacing to 0.5 nm, and also controlled the channel spacing precisely to 1.0 nm using the same trimming technique.