Long-haul dissemination of the Swiss national time-scale UTC(CH) in a telecommunication fiber network via White Rabbit

White Rabbit has emerged as a promising technology for time-scale dissemination, providing resilience to satellite techniques. To achieve state-of-the-art synchronicity at the sub-nanosecond level in a White Rabbit network, a complete characterization of physical effects, components, and the reference time scale is required in order to remove systematic offsets not compensated by the White Rabbit protocol. Due to this complexity, only a few long-range White Rabbit networks can claim synchronicity to a national time scale on a sub-nanosecond level. We present here such a network with the vocation to disseminate the Swiss official time-scale UTC(CH). To that end, the White Rabbit network layer is multiplexed into two dark channels in the L-band of a deployed telecommunication fiber network covering nearly 500 km of fiber. We characterize its performance in terms of stability and accuracy and find an uncertainty of 289–415 ps. This validates its potential to disseminate UTC(CH) at the sub-nanosecond accuracy and precision level. The results confirm that White Rabbit provides the necessary performance to distribute and compare the national time-scale UTC(CH) over optical fiber networks at the national and eventually at international levels.