Effect of RI uncertainty in optical waveguides for quantum technology

modes has a reliable quantum cross-talk length. Still, if the transverse refractive index distribution is imperfect, it is reduced to 250 [um]. We also compare the effect of core-clad wall imperfection with that of inhomogeneity in the waveguide's refractive index and show that the wall imperfection has a severe destructive impact and can reduce the quantum cross-talk length from > 30[mm] to 11.964[mm].