We demonstrate, by experiment and numerical calculations, temperature-independent subwavelength grating waveguides with a periodic composite core composed of alternating regions of silicon and SU-8 polymer. The polymer has a negative thermo-optic (TO) material coefficient that cancels the large positive TO effect of the silicon. Measurements and Bloch mode calculations were carried out over a range of silicon-polymer duty ratios. The lowest measured TO coefficient at a wavelength of 1550nm is 1:8 × 10 -6 K-1; 2 orders of magnitude smaller than a conventional silicon photonic wire waveguide. Calculations predict the possibility of complete cancellation of the silicon waveguide temperature dependence.

Optics Letters
Department of Electronics

Schmid, J.H. (J. H.), Ibrahim, M. (M.), Cheben, P. (P.), Lapointe, J. (J.), Janz, S. (S.), Bock, P.J. (P. J.), … Xu, D.-X. (D. X.). (2011). Temperature-independent silicon subwavelength grating waveguides. Optics Letters, 36(11), 2110–2112. doi:10.1364/OL.36.002110