Stabilized Fiber-Optic Link-Propagation Delay for Timing Distribution in Particle Accelerator Facility

B. Batagelj, J. Tratnik and M. Vidmar

Abstract:	In a particle accelerator facility a precise timing-distribution system has a strong impact on performance of a several hundred meters long machine. In this scientific field, the synchronization/timing-distribution requirements for added jitter (short-term stability) and drift (long-term stability) are below a few tens of femtoseconds. At the beginning this paper addresses main issues, which must be taken into consideration when designing a synchronization/timing system, such as transmission medium and timing frequency. The designed electro-optical synchronization system, which consists of an electrooptical transmitter, located near a low-jitter master RF oscillator, and an opto-electrical receiver, located at a remote location is described. Both units are connected with a single-mode optical fiber, connected in a loop-back to achieve stabilization of propagation delay. The optical transmission path has delay variations mainly due to temperature stretching of the fiber, very high thermal coefficient of the fiber refractive index and last but not least, microphonics and vibrations. Stabilization mechanisms of fiber-optic link-propagation delay are explained. Results of added jitter and drift over period of 24 hours are presented. The demonstrated synchronization system can be a very good candidate for a precise RF-clock distribution with low fluctuations in propagation delay.
Published in:	Proceedings of the 43rd Annual Precise Time and Time Interval Systems and Applications Meeting November 14 - 17, 2011 Hyatt Regency Long Beach Long Beach, California
Pages:	35 - 44
Cite this article:	Batagelj, B., Tratnik, J., Vidmar, M., "Stabilized Fiber-Optic Link-Propagation Delay for Timing Distribution in Particle Accelerator Facility," Proceedings of the 43rd Annual Precise Time and Time Interval Systems and Applications Meeting, Long Beach, California, November 2011, pp. 35-44.
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