Two Color One Way Time and Frequency Transfer in an Urban Optical Fiber Data Communication WDM Network
Paper in proceedings, 2012
The two color one-way frequency transfer in optical fiber is an alternative method to two-way time and frequency transfer that is useful if there are unknown asymmetries in the connection or when broadcasting of the timing signal is required. The method is possible to use in existing in-frastructure and is able to coexist with data channels for example in WDM systems, and as it performs a dynamical control of total transfer time, it enables a real-time phase stable output signal.
The performance of the technique has been shown in lab experiments utilizing temperature steer-ing of a spool of fiber at the receiver  or theoretical models for an electrical delay after recep-tion . Both methods benefit from a higher frequency of the control signal (> 1GHz), which is combined with the requested timing signal at 5 – 100 MHz.
Recent results from an implementation in a commercial optical metro fiber network will be pre-sented. The system compares two Cesium clocks, which are also compared through GPS for ref-erence. The results will both show the performance of the technique, as well as an analysis of the uncompensated variations of a frequency transfer in installed fiber in a metro area.