A Potential Factor Affecting the Rapid Change of SOP in OPGW

Starting from the coupled mode equations, we theoretically analyzed the Faraday optical rotation effect and electro-optic Kerr (EO) effect on the variation of state of polarization (SOP) on the Poincaré sphere, and pointed out that the electro-optic Kerr effect may be a potential factor affecting the rapid change of the Stokes vector S3 of the polarization state of the signal light in OPGW. To verify this hypothesis, we simulated the scenario of lightning striking OPGW from actual experiments, compared the theoretical calculation and experimental testing of the maximum lateral and longitudinal rotation rates, and analyzed the oblique SOP trajectory changes on the Poincaré ball during discharge. The measurement results enhanced our confidence in the hypothesis. The electro-optic Kerr effect may make a significant contribution to the rapid change of polarization state, and under real lightning conditions, its induced rotation rate may reach Mrad/s, which is one of the reasons for the chaotic changes in SOP on the Poincaré sphere in real measurements.