<title>Polymeric digital optical switch with a linear branch and an optimized coupling region</title>

Abstract

A digital optical switch with a modified coupling region is designed by using the beam propagation method, and it is fabricated by employing an electro-optic polymer rib waveguide formed by the reactive ion etching method. The structure of the modified coupling region and its refractive index profile are designed to optimize the mode coupling in the Y-branch, since the coupling determines the switching performance. Therefore, the switching performance of the device may be enhanced with a fixed device length. The practical optimization of coupling region is performed by using the photobleaching method after the device fabrication. The crosstalk has been experimentally improved by as great as 4 dB by introducing the modified coupling region. The drive voltage is also reduced by more than 30 percent.