Demonstration of alignment error-free patterning of tapered waveguide using Fixed Beam Moving Stage e-beam lithography

We present a method to write a tapered waveguide using fixed-beam-moving-stage (FBMS) in an electron-beam lithography system. FBMS allows writing of large patterns without stitch-error, however, restricts only a few primitive shapes. For patterning tapers, a combination of FMBS with area-mode is used that typically results in alignment errors. The proposed method offers smooth and alignment-error-free tapering of sub-micron featured Silicon waveguide. We experimentally demonstrate a fully FBMS patterned photonic circuit with power splitter, wire-to-slot coupler, slot waveguide and a slotted ring resonator. The device response with insertion loss -1.35dB is measured using a tunable laser source around 1550 nm wavelength.