Ink-jet printed Optical Taper Structures for Planar Optronic Systems

Planar optronic systems promise to be a feasible alternative for well-established electronic systems, as they are potentially faster, more robust, cheaper, and lighter. While the waveguides that guide the optical signal from one element to another are fabricated by flexographic printing, this manufacturing technique is unable to print on raised structures like laser diodes or photodetectors. For such a situation, a contactless deposition method like ink-jet printing is required. We used a Dimatix DMP 2831 laboratory printer to investigate the effect of several process parameters on morphology and functionality of optical taper structures between flexographically printed waveguides and 650 nm laser diode chips on PMMA foil. Two UV-curable inks were investigated, an in-house developed acrylate-based monomer, and Ink Epo, a commercially available, epoxy based ink. The shape of the taper structures can be controlled through substrate temperature and deposited ink volume, while plasma treatment caused the ink to encase the complete chip.