Precise center wavelength triming of vertically coupled microring resonator filter by direct UV irradiation to ring core

摘要

Vertically coupled microring resonator (VCMRR) filter is an attractive Add/Drop wavelength filter due to its functionallity, compactness, and the possibility of dense integration resulting from the cross-grid configuration. However, the accuracy of center wavelength was not satisfactorily enough for the DWDM systems. Thus, we developed a precise UV trimming of the center wavelength, which uses the direct UV irradiation to the Ta{sub}2O{sub}5-SiO{sub}2 ring core. As a result, we achieved O.48nm of center wavelength shift. The center wavelength shift was enhanced to 0.8nm, and the wavelength shift was stabilized for 2400 hours by hydrogen loading. In addition, we investigated the index change of the SiN film as a high A core material, and found a very large index change by UV exposure.