wavelength function in dispersion.jl yielding unexpected value

using LumenManufaktur

dp = DispersionORCA
ior = 1.3860809773599998
w = 700.0
resulting_w = LumenManufaktur.wavelength(dp, ior, w, 1.0e-5)
println("Resulting wavelength: ", resulting_w)

returns a negative wavelength. I think something is not caught correctly. In some cases it might also be that the break condition inside the wavelength function is never met.