Abstract

In NASA’s Deep Space Network (DSN), the phase stability of the clock synchronization link interconnecting various antenna sites ultimately determines the system’s tracking accuracy. Use of a multimode optical fiber to improve the stability of this loop was shown previously to be comparable with the best coaxial cables.¹ Other studies have shown that the phase temperature coefficient (TC) of bare optical fibers is largely dominated by core refractive- index changes resulting from electron polarizability shifts² and cladding-induced stress-optic effects.^3,4 Ruggedized cabled fibers can exacerbate the latter effect, but oddly these have remained largely unexplored.⁵ In this paper, the phase TC of two ruggedized optical-fiber cable structures is studied: one single-mode fiber housed in a loose-tube cable and a multimode fiber housed In a solid cable.

© 1984 Optical Society of America