Fig. 2

Optimization of the horizontal slot waveguide: a Confinement factor (normalized power) in the slot region as a function of the thickness of the low index layer (slot) and the HI-layers. b Intensity in the LI-layer. c Effective index of the fundamental quasi-TM slot mode. The hatched regions exclude thicknesses for which the characteristic length (1/γ _s) is shorter than the slot thickness. d Effective index difference when the cladding is air and when it is a material with n _c = 1.6 (the green arrow indicates increasing loading strip thickness)