Towards high-rate fabrication of photonic devices utilizing a combination of roll-to-roll compatible imprint lithography and ink jet printing methods

Traditionally, polymer photonic devices are fabricated using clean-room processes such as photolithography, electron beam lithography, reactive ion etching (RIE) and lift-off methods etc, which leads to long fabrication time, low throughput and high cost. We describe in this paper a novel process for fabricating polymer photonic devices using a combination of imprinting and ink jet printing methods, which provides high throughput on a variety of rigid and flexible substrates with low cost. Particularly, we demonstrate a thermo-optic switch and an electro-optic modulator. In the rib waveguide patterning, the imprint lithography transfers the waveguide pattern from a soft mold to UV-15LV bottom cladding layer. The soft mold is replicated from a silicon master mold and rendered hydrophobic to ensure successful de-molding. Ink jet printing method is used to deposit the core layer in thermo-optic switch and electrode layers in electro-optic modulator. Compared to spin-coating method, the use of print-on-demand method greatly reduces material consumption and process complexity. Every step involved has the potential to be fully compatible with roll-toroll (R2R) volume production. For example, the soft mold can be wrapped around a cylinder to realized roll-to-roll imprinting. By combining R2R imprint lithography with ink jet printing, fabrication of large volume and large area multi-layer polymer photonic devices can be realized.