Dispersion independent long-haul photon counting OTDR

TL;DR

This paper introduces a dispersion-independent photon counting OTDR technique that maintains high spatial resolution over long fiber links, overcoming dispersion effects that typically degrade resolution in traditional systems.

Contribution

The authors propose a novel dispersion-independent PC-OTDR scheme based on an infinite backscatter technique, enabling high-resolution fiber monitoring over long distances.

Findings

Achieved high spatial resolution over 50 km fiber links

Demonstrated resolution independence from fiber dispersion

Enabled long-haul fiber fault monitoring with high performance

Abstract

Photon counting optical time-domain reflectometry (PC-OTDR) based on the single photon detection is an effective scheme to attain the high spatial resolution for optical fiber fault monitoring. Currently, due to the spatial resolution of PC-OTDR is proportional to the pulse width of a laser beam, short laser pulses are essential for the high spatial resolution. However, short laser pulses have a large bandwidth, which would be widened by the dispersion of fiber, thereby causing inevitable deterioration in spatial resolution, especially for long-haul fiber links. In this letter, we propose a scheme of dispersion independent PC-OTDR based on an infinite backscatter technique. Our experimental results -with more than 50 km long fiber - show that the spatial resolution of the PC-OTDR system is independent with the total dispersion of the fiber under test. Our method provides an avenue for developing the long-haul PC-OTDR with high performance.