Fabrication of integrated structures for coupling VCSEL to fibre

Thick photoresists are typically used to produce micro-mechanical elements for fibre coupling and alignment tasks. By suitable illumination, however, also optical functions can be integrated into the structures. We have examined the possibility of exposing thick resist under different angles, to realise integrated deflection structures, including 45° mirrors. Some challenges of exposing 45° structures are light coupling and the elimination of surface reflexes. Due to refraction, the maximum angle is limited to about 60°. Using a coupling prism the angle can be decreased to less than less than 45°. We demonstrate an integrated fibre mounting and coupling structure for an automatic alignment of fibres and VCSELs.