*Article* **Optical Polymer Waveguides Fabricated by Roll-to-Plate Nanoimprinting Technique**

**Vaclav Prajzler 1,\* , Vaclav Chlupaty <sup>1</sup> , Pavel Kulha 1,2,\* , Milos Neruda <sup>1</sup> , Sonja Kopp <sup>2</sup> and Michael Mühlberger <sup>2</sup>**

> <sup>1</sup> Department of Microelectronics, Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, 168 27 Prague, Czech Republic; chlupvac@fel.cvut.cz (V.C.); nerudmil@fel.cvut.cz (M.N.)

**\*** Correspondence: vaclav.prajzler@fel.cvut.cz (V.P.); pavel.kulha@profactor.at (P.K.); Tel.: +420-22435-2338 (V.P.); +43-7252885-431 (P.K.)

**Abstract:** The paper reports on the properties of UV-curable inorganic-organic hybrid polymer multimode optical channel waveguides fabricated by roll-to-plate (R2P) nanoimprinting. We measured transmission spectra, refractive indices of the applied polymer materials, and optimized the R2P fabrication process. Optical losses of the waveguides were measured by the cut-back method at wavelengths of 532, 650, 850, 1310, and 1550 nm. The lowest optical losses were measured at 850 nm and the lowest average value was 0.19 dB/cm, and optical losses at 1310 nm were 0.42 dB/cm and 0.25 dB/cm at 650 nm respectively. The study has demonstrated that nanoimprinting has great potential for the implementation of optical polymer waveguides not only for optical interconnection applications.

**Keywords:** optical planar waveguides; roll-to-plate R2P nanoimprinting; UV-curable polymers; inorganic-organic hybrid polymer; optical losses
