Tunable hydrogel microlens with built-in polymer waveguide and fiber clamp for MEMS applications

This paper presents a photolithographically patterned hydrogel microlens with tunable focal length. EpoClad and EpoCore epoxies are microfabricated to form the integrated optical platform, combining the mechanical fiber clamps, waveguides and the gel setup. The optical focus of the microlens can be adapted by controlling the absorption of a fluid. The focal length can be modulated from 0.3 mm to 1 mm. Placed between two optical waveguides, the microlens acts as light intensity modulator that can change the transmitted intensity up to a factor of 8.