Figure 4

(a) Mode overlap for light transmitted across a through-hole in an optical fibre with parabolically-curved convex input and output facets, as a function of the coefficient of curvature of the surfaces and the distance of closest approach of the input and output faces. (b) MOTL as a function of the coefficient of curvature with the distance of closest approach equal to 20 μm. In (a) the black markers indicate the locations of the data points resulting from FDTD simulations, while the colour map is a cubic interpolation between the measured points.