Discover and analysis of the fast phase changes due to lightning strikes on optical ground wire

The state of polarization (SOP) dynamics in optical ground wires (OPGWs) under lightning strikes is critical for polarization-sensitive communication systems. This study reveals a previously unreported fast phase change effect alongside SOP rotation, observed through controlled lightning current tests (20–100 kA) on central tube and layer-stranded OPGWs. While the rotation angle follows Faraday effect predictions (0.007–0.011 rad/kA), the phase shift exhibits a distinct nonlinear dependence on current, reaching 510 krad/s in layer-stranded designs—a phenomenon attributed to perpendicular magnetic field components activating magneto-optical Kerr effect (MOKE) or Cotton-Mouton effect (CME). Structural asymmetry in layer-stranded OPGWs amplifies phase changes by 3× compared to central tube counterparts, as confirmed by thermal/vibration tests showing 0.42 ps/km DGD variation and 87 Hz resonance peaks. These findings necessitate dual compensation for SOP and phase transients in DSP algorithms, with central tube OPGWs offering superior stability (Fstab = 0.02 vs. 0.07).