DEVICE FOR DOUBLE REFRACTION MEASURING AND METHOD FOR MEASURING DISPERSION OF FIBER MODES POLARISATION (VERSIONS) AND OPTICAL FIBER (VERSIONS) Russian patent published in 2010 - IPC G01M11/02 

FIELD: measurement technique.

SUBSTANCE: invention refers to methods for measuring polarisation modes dispersion (FMD) of optical fiber in various states, device for double refraction measuring and optical fiber. The invention is based on possibility to obtain two-pass Jones matrix R(z) for the first interval (0,z) from initial point of measurement 0 in optical fiber to measure to prescribed position z, and two-pass Jones matrix R (z +Δz) for the second interval (0, z +Δz) from initial point of measurement 0 to position z +Δz, differing from position z, to determine secular values ρ₁ and ρ₂ for matrix R(z +Δz)R(z)^-1 and to obtain double refraction in infinitely small interval Δz from position z to position z +Δz, by resolving following equations (1) and (2), (1) , where φ specifies phase difference between linear-polarised elements due to double refraction; Δn specifies double refraction; λ specifies wave length, and using measured double refraction and its connection with FDM to determine FDM.

EFFECT: improvement of accuracy of FDM measurement in short time period and on short section of optical fiber.

25 cl, 21 dwg