Core position alignment in polymer optical waveguides fabricated using the Mosquito method

We fabricate multimode polymer optical waveguides with circular graded-index (GI) cores which are aligned in parallel at desired positions using the Mosquito method. In the Mosquito method, three-dimensional wiring patterns can be formed with a simple process. However, the core position is likely to deviate from the designed position because of multiple fabrication factors. Hence, in this paper, the dominant parameters to influence on the core height in the cladding are investigated both theoretically and experimentally. In particular, a linear relationship between the core height and the needle-tip height is confirmed with theoretical fluid analysis. Using this relationship, we succeeded in fabricating a waveguide in which the maximum variation of the core height from the designed value is controlled to be less than 10 µm.