DETAILS, FICTION AND BIREFRINGENT CRYSTAL

各向异性透明晶体如方解石、石英等的折射率，是其固有的特性，称为永久双折射。For optical fibers and also other waveguides, it is a lot more appropriate to contemplate the real difference of effective refractive indices. This is often right connected to the primary difference in imaginary values from the propagation