C.J. Chen, C.A. Husko, I. Meric, K.L. Shepard, C.W. Wong, W.M. J. Green, Y.A. Vlasov, and S. Assefa, “Deterministic tuning of slow-light in photonic crystal waveguides through the C and L bands by atomic layer deposition,” Applied Physics Letters, 96, 081107 (2010).

We demonstrate digital tuning of the slow-light regime in silicon photonic-crystal waveguides by performing atomic layer deposition of hafnium oxide. The high group-index regime was deterministically controlled redshift of 14010 pm per atomic layer without affecting the group-velocity dispersion and third-order dispersion. Additionally, differential tuning of 11030 pm per monolayer of the slow-light TE-like and TM-like modes was observed. This passive postfabrication process has potential applications including the tuning of chip-scale optical interconnects, as well as Raman and parametric amplification.