Abstract

Line-monitoring (LM) systems are employed in installed undersea transmission lines to monitor amplifier status and locate faults. A LM system compatible with both optical soliton transmission using sliding-frequency guiding filters¹ and the "continuous loop-back" approach to LM² has not yet been addressed. For solitons to be employed in undersea systems, a LM mechanism must exist. LM systems currently being installed for NRZ systems use a low frequency pseudo-random pattern superimposed on the data, a small fraction of which is coupled back onto a fiber on which light propagates in the opposite direction.³ This received signal is then processed to determine the status of individual amplifiers.⁴ In soliton systems, because sliding filters are employed to combat Gordon- Haus jitter, only nonlinear soliton pulses survive; any modulation on the solitons is "washed out." Hence, the traditional LM technique cannot be used.

© 1996 Optical Society of America