Direct fabrication for multimode/single-mode polymer optical waveguides on printed circuit board using the mosquito method

We have proposed the Mosquito method to fabricate polymer optical waveguides with graded-index (GI) circular cores and demonstrated their excellent optical property. We have employed glass substrate which has a smooth surface for the waveguide fabrication using the Mosquito method. However, waveguides integrated on PCBs are expected for the on-board optical interconnection applications. The Mosquito method have a capability to directly fabricate waveguides on PCBs.In this paper, optical waveguides are fabricated on PCBs directly using FR-4 substrates which are a standard PCB. Here, the waveguide facet termination process is very important. Generally, waveguide ends are cut with the PCB using a dicing saw or polished after fabricating the waveguides separately from PCBs. In this paper, we propose a new waveguide facet termination process, which could be involved in the Mosquito method, and report the improvement of coupling efficiency to other optical components because the waveguide ends have sufficiently smooth surfaces.