D. V. Gorbatov, A. N. Dorozhkin, A. Yu. Igumenov, V. A. Konyshev, T. O. Lukinykh, O. E. Nanii, A. G. Novikov, V. N. Treshchikov, R. R. Ubaydullaev
- T8 NTC LLC
- Faculty of Physics, Lomonosov Moscow State University
- Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Moscow Region
- “T8” LLC, Moscow
- Kotelnikov Institute of Radioengineering and Electronics, Fryazino Branch, Russian Academy of Sciences
Abstract: A numerical experiment for the light passing through a section of an optical cable in a ground wire during a lightning strike is performed, and the ‘isotropy effect’ of the sections of time profiles of the rotation speed of the state of polarization is discovered and explained. The shapes of the time profiles for anisotropic and isotropic fibres virtually coincide in short sections at the beginning and at the end of the time profile of the change in polarization, but differ significantly in the middle part. This behaviour of the time profiles is determined by the smallness of the length of the interaction of the light with the region of a rapid change in the magnetic field at the beginning and at the end of the lightning front, while the effect of the magnetic field on short sections of an anisotropic fibre almost coincides with that on sections of isotropic fibre of the same length. Using the model of light propagation in fibre with a random distribution of linear birefringence, located in the magnetic field of the lightning, a formula is obtained for calculating the matrix rotation speed of the polarization state for an extended fibre.
Keywords: effect of isotropy of sections of time profiles of the speed of rotation of the polarization state, Faraday effect in an optical fibre, state of polarization, overhead fibre-optic communication lines, fast rotation of the polarization state, optical ground wire.
Received: 29.06.2022
Revised: 08.08.2022