Visible light trimming of coupled ring-resonator filters in As2S3 chalcogenide glass technology

Photosensitivity in chalcogenide glass waveguide allows for a permanent refractive index change by means of light exposure [1]. This property can be usefully exploited for post-fabrication trimming of integrated optical devices in order to compensate for fabrication imperfections and alleviate the need for restrictively tight fabrication tolerances [2]. In this work, visible light trimming is exploited to optimize the performance of coupled resonator filters realized by cascading micro-ring resonators in As2S3 glass technology.