Long, stitch-free slot waveguide with s-bend tapered couplers for IR-sensing applications using electron beam lithography

We use the fixed beam moving stage (FBMS) electron beam lithography technique to pattern a 10 mm long slot waveguide with s-bend tapered double-tip couplers. The fabrication method solves two major limitations of the FBMS mode, namely, the requirement for fixed-width structures and the incidence of stage placement drift for patterns involving elements of different widths. This has been achieved by fracturing the outline of the structure into fixed-width elements of gradually increasing width and creating intermediate overlap areas between the elements to mitigate the stage placement drifts.