Hybrid lithography approach for single mode polymeric waveguides and out-of-plane coupling mirrors

Abstract

This paper describes technology and process development for a hybrid lithography approach pairing UV-lithography for planar single mode waveguides with 2-photon-polymerization direct-laser-writing for out-of-plane coupling mirrors. Improvements to multi-layer direct patterning of OrmoCore/-Clad material system using UV-lithography are presented. Near square core cross sections are achieved. Minimum alignment accuracy at ≈ 3 μm is observed. Cut-back measurement on single mode waveguides shows attenuation of 0.64 dB cm-1 and 1.5 dB cm-1 at 1310 nm and 1550 nm respectively. Up to 2.5-times increase of shear-strength after thermal exposure up to 300 C is found using shear tests and compared for various surface treatments. Mechanical compatibility to reflow soldering is derived. An extensive study on the pattering of ORMOCER® using 2-photon-polymerization is performed. Flat 45-micro mirrors with sub-10 μm dimensions are 3D-printed both in OrmoCore and OrmoComp. Outlook to further research on hybrid lithography integration approach is given.