All-polymeric planar waveguide devices based on a gas-assisted thermal imprinting technique

In order to improve accuracy of replication and to simplify the fabrication process for imprinted all-polymeric planar optical waveguides and devices, the three-stage thermal imprinting technique with gas pressure load were developed to optimize the cross-sectional profile morphologies of polymer trenches directly fabricated on polymethylmethacrylate (PMMA) sheets. As a result, our investigation found that the choice of the imprinting pressure was directly dependent on the imprinting temperature. The shortest imprinting temperature holding time was correlated with combination of them. The conformal polymer waveguide patterns were obtained under uniform and low gas pressure. As a verification for a simple and efficient gas-assisted thermal imprinting technique, the 8 × 8 μm² solid PMMA based all-polymeric single-mode planar waveguides and planar lightwave circuit devices including a 1 × 2 splitter and a 1 × 4 splitter were fabricated and characterized at the wavelength of 1550 nm. The propagation loss coefficient of these all-polymeric planar waveguides was measured to be 1.63 ± 0.02 dB/cm.