D-LAF50-25 by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.7347\,\lambda^2}{\lambda^2 - 0.0226667} + \frac{1.33717\,\lambda^2}{\lambda^2 - 0.00601677} + \frac{1.13513\,\lambda^2}{\lambda^2 - 95.7513}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[1.53 \times 10^{-6} + 2(1.43 \times 10^{-8})\,\Delta T + 3(-3.83 \times 10^{-11})\,\Delta T^2 + \frac{5.87 \times 10^{-7} + 2(4.1 \times 10^{-10})\,\Delta T}{\lambda - 0.222}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$