Abstract
To increase a transmission capacity of existing OPGW in future, a coherent optical fiber communication is effective but it needs a control of polarization state of optical signal. In OPGW, the polarization state may be possibly fluctuated by alternative current or lightning and it may be severer than any other environments. But the optical polarization characteristics of OPGW have not been clarified.
This paper describes the experimental results of transient states of optical polarization by large impulse current in OPGW (200m length). The impulse current is maximum 16kA at peak with 1×10μs rise and tail time. Polarization states are measured by a real time stokes analyzer with 10MHz band width. As a result, the maximum change of polarization state on Poincare sphere is about 70degrees and the rise time is about 12μs, which is much longer than the impulse current rise time of 1μs. It is found that the polarization rise time depends on the inductance of spiral current along twisted conductor elements of OPGW, which makes magnetic field along the fiber in OPGW as occurs Faraday effect.
