Transmission of Time and Frequency Signals Through an Optical Fiber

CSIR-NPL has for the first time used optical fibers to transmit standard time and frequency signals. This has been done to transport standard time and frequency signals from Primary Time Scale to a new Backup Time Scale. Time and frequency signals of 1 PPS and 5 or 10 MHz are required to be accurately transported for calibration of an ensemble of clocks, providing traceability to other national standards and comparison of two-time scales. To accomplish this task, use of Optical Fibers as a transmission medium is preferred over the conventional RF cable transmission medium as it provides the low attenuation [1], electrical isolation, low power loss, and cost-effectiveness. The paper describes the optical fiber link and its characterization.