Estimating refractive index structure constant and extinction coefficient under misalignment

This paper presents two methods, named the irradiance fitting method and the irradiance integration method, for the estimation of refractive index structure constant (Cn2) and extinction coefficient under misalignment. Validations of the methods are carried out based on experimentally obtained speckle images. These two methods are feasible and accurate regardless of whether the optical axis misalignment distance is calibrated, which provides an effective and convenient approach for free space optical communication (FSOC) atmospheric channel research.