Circular core single-mode polymer optical waveguide fabricated using the Mosquito method with low loss at 1310/1550 nm.

We fabricate low-loss single-mode (SM) polymer optical waveguides using a photomask-free simple technique named the Mosquito method. The insertion losses of a 5-cm long SM polymer waveguide fabricated are 2.52 dB and 4.03 dB at 1310- and 1550-nm wavelengths, respectively. The coupling loss between a single-mode fiber and the waveguide is as low as 0.5 dB including the Fresnel reflection. The 0.5-dB misalignment tolerance in the radial direction is ± 2.0 μm at 1550 nm. The Mosquito method is promising for fabricating SM polymer optical waveguides compatible with silicon photonics chips.