We demonstrate low-loss silicon slot waveguides patterned with 248 nm deep-UV lithography and filled with atomic layer deposited aluminum oxide. Propagation losses less than 5 dB/cm are achieved with the waveguides. The devices are fabricated using low-temperature CMOS compatible processes. We also demonstrate simple, compact and efficient strip-to-slot waveguide couplers. With a coupler as short as 10 µm, coupling loss is less than 0.15 dB. The low-index and low-nonlinearity filling material allows nonlinearities nearly two orders of magnitude smaller than in silicon waveguides. Therefore, these waveguides are a good candidate for linear photonic devices on the silicon platform, and for distortion-free signal transmission channels between different parts of a silicon all-optical chip. The low-nonlinearity slot waveguides and robust couplers also facilitate a 50-fold local change of the waveguide nonlinearity within the chip by a simple mask design.
- Integrated optics materials
- Nanostructure fabrication
- Guided wave applications
Säynätjoki, A., Karvonen, L., Alasaarela, T., Tu, X., Liow, T. Y., Hiltunen, M., Tervonen, A., Lo, G. Q., & Honkanen, S. (2011). Low-loss silicon slot waveguides and couplers fabricated with optical lithography and atomic layer deposition. Optics Express, 19(27), 26275-26282. https://doi.org/10.1364/OE.19.026275