Skip to main content
. Author manuscript; available in PMC: 2019 Jun 13.
Published in final edited form as: Microelectron Eng. 2018 Mar 28;195:41–49. doi: 10.1016/j.mee.2018.03.023

Fig. 2.

Fig. 2

Evolution of kt inside the taper as a function of the waveguide diameter. Several values of kt in the non-tapered region of a NA = 0.66 TF are shown (from 0.06·2π/λ to 0.60·2π/λ with steps of 0.06·2π/λ). The grey-shaded area represents a non-tapered region in which these kt values remain constant until the waveguide starts narrowing. The two dashed lines represent the bound imposed by the different confinement mechanisms for uncoated and metal-coated TFs, kt, max(u) = 0.66·2π/λ and kt, max(m) = 1.62·2π/λ, respectively.