H-ZK7A by CDGM

$$n(\lambda) = \sqrt{1 + \frac{0.938066\,\lambda^2}{\lambda^2 - 0.00438468} + \frac{0.623492\,\lambda^2}{\lambda^2 - 0.0169391} + \frac{1.00587\,\lambda^2}{\lambda^2 - 93.2751}}$$

$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[3.89 \times 10^{-7} + 2(1.54 \times 10^{-8})\,\Delta T + 3(-4.77 \times 10^{-11})\,\Delta T^2 + \frac{3.87 \times 10^{-7} + 2(5.71 \times 10^{-10})\,\Delta T}{\lambda - 0.198}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$