nSi 3.5 Refractive index, silicon (Si) nSiO2 1.445 Refractive index, silica (SiO2) deltan 0.0075 Relative index difference nCore nSiO2/sqrt(1-2*deltan) Refractive index, core (doped SiO2) alphaSi 2.5e-6[1/K] Thermal expansion coefficient, silicon alphaSiO2 0.35e-6[1/K] Thermal expansion coefficient, silica ESi 110[GPa] Young's modulus, silicon ESiO2 78[GPa] Young's modulus, silica nuSi 0.19 Poisson's ratio, silicon nuSiO2 0.42 Poisson's ratio, silica rhoSi 2330[kg/m^3] Density, silicon rhoSiO2 2203[kg/m^3] Density, silica B1 0.65e-12[m^2/N] First stress optical coefficient B2 4.2e-12[m^2/N] Second stress optical coefficient T1 20[degC] Operating temperature T0 1000[degC] Reference temperature lambda0_ewfd 1.55[um] Free space wavelength