Impact of Transceiver Selection on Synchronization Accuracy in White Rabbit Networks

TL;DR

The paper tackles how transceiver choice affects White Rabbit synchronization accuracy under environmental-induced chromatic dispersion. It employs a laboratory setup with a 20 km G.652.D fiber in a climatic chamber to compare BiDi WDM (1310/1550 nm) and DWDM (Ch33/Ch34) for WR time transfer. The key finding is that DWDM transceivers dramatically reduce temperature-induced offset drift, achieving about $17.0$ ps of drift under a $60^{\circ}C$ change versus $220.4$ ps for BiDi, a ~13× improvement. This demonstrates that DWDM transceivers are essential for high-precision WR synchronization in real-world, thermally varying optical networks, guiding practical transceiver selection for WR deployments.

Abstract

Achieving optimal synchronization accuracy between two White Rabbit devices hinges on the proper selection of transceivers, which act as electro-optical converters connecting WR devices to the optical network infrastructure. The correct choice of transceivers can significantly improve resilience to changes in the time offset between WR devices due to temperature fluctuations in the connecting optical fiber. To compare the performance of BiDi WDM and DWDM transceivers, an experimental setup was established under laboratory conditions to simulate a real optical network used for distributing precise time and frequency between two remote locations. The optical connection was emulated by integrating a 20 km G.652.D optical fiber into a climatic chamber, which provided variable environmental conditions similar to those experienced in real applications. The study compared BiDi WDM 1310/1550 nm transceivers with DWDM Ch33/Ch34 transceivers. Results showed that DWDM transceivers exhibited nearly thirteen times less sensitivity to temperature-induced changes in the optical connection, leading to a smaller time offset. Therefore, for achieving the highest accuracy in synchronizing WR devices in practical applications, DWDM transceiver technology is essential.

Figures (4)

• Figure 1: Optical setup for measurements with BiDi WDM and DWDM transceivers.
• Figure 2: Block diagram of the instrumentation setup for measurement.
• Figure 3: Measurement results of cRTT and $\Delta t$ versus optical fiber temperature for BiDi WDM transceivers.
• Figure 4: Measurement results of cRTT and $\Delta t$ versus optical fiber temperature for DWDM transceivers.