Study on the Asymmetry of G.655 Optical Fiber for DWDM-based Clock Distribution and Synchronization Systems

The measurement and compensation for the asymmetry of optical fiber transmission delay are essential steps in White Rabbit-based clock distribution and synchronization systems. Based on the chromatic dispersion analysis, using G.655 fiber instead of the commonly used G.652 fiber can reduce the asymmetry, thereby effectively simplifying the compensation process of clock synchronization systems with dense wavelength division multiplexing (DWDM) optics. In this paper, we present the theoretical analysis and experimental measurement results of using G.655 fiber in such systems. The test results show that over a 5-km fiber connection, its asymmetry coefficient is one order of magnitude smaller than that of the commonly used G.652 fiber. That means the asymmetry can be completely ignored even for the system achieving synchronization accuracy around 10 ps.