Laser trimming of SiON components for integrated optics

Integrated optical directional couplers were realized by thin SiON films, deposited on silicon substrates by low pressure chemical vapor deposition (LPCVD). To reproduce a desired coupling ratio, a spatially selective trimming of integrated optical components was developed to compensate the technological deviations from ideal values of geometry and refractive index. Starting from the actual coupling ratio, any other value could be obtained by annealing the SiON material with a pulsed CO/sub 2/ laser beam within 3%, by reducing the refractive index of near oxide films.<
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