| Popis: |
Periodically segmented waveguide (PSW) mode expanders can be realized simply, using a single step lithography. In this paper such devices are studied numerically, with respect to high-/spl Delta/ silica waveguides and InP strip waveguides. The efficiency of such expanders is shown to be high, for proper length and segmentation period, and back reflection is negligible. It is shown that lithographical grids of 0.125-0.25 /spl mu/m resolution are sufficient to obtain efficient out-coupling. Basic design rules are outlined. > |
