Coupling structure for optical fibres and process for making it

Abstract

A coupling structure for coupling optical radiation, i.e., light, between an optical fibre and an optical device, e.g., a laser diode or a photodiode. The coupling structure has an optical through-via which guides the optical radiation to or from the optical fibre. Light exiting the fibre travels through a guidance channel so it remains substantially confined to a narrow optical path that mimics the fibre core. Conversely, light enters the fibre after having traveled through the guidance channel. The guidance channel has a first core region, the 'channel core', having first refractive index surrounded by a second region, the 'channel cladding' having a second refractive index smaller than the first refractive index. The coupling structure, including the guidance channel, is preferably made of semiconductor-based material, more preferably of silicon-based material. The guidance channel is preferably silicon oxide. The coupling structure further has a fibre drive-in element, which facilitates insertion and alignment of the optical fibre to the guidance channel.