Microfabrication and test of pre-aligned fiber bundle couplers with integrated microlens array

This paper describes the design, microfabrication and testing of a pre-aligned array of fiber couplers with integrated out-of-plane microlenses using direct UV lithography of SU-8. The fiber bundle coupler includes a refractive microlens array and two fiberport collimator arrays. With the optical axis of the pixels parallel to the substrate, each pixel of the microlens array can be pre-aligned with the corresponding pixels of the fiberport collimator array as defined by the lithography mask design. This out-of-plane polymer microlens array was pre-aligned with the fiber collimator arrays with no additional adjustment and assembly required. This novel approach helps to dramatically reduce the running cost and improve the alignment quality and coupling efficiency.