Abstract

A variety of techniques for multiplexing interferometric sensors have been reported over the past severa1 years,^1-4 utilizing addressing techniques common to communications systems, e.g., time, frequency, and wavelength-division multiplexing. Al-though the technical issues associated with sensor multiplexing are similar to those in LAN type communication systems, the multiplexing of sensor outputs often presents a considerable problem with regard to the array topology, as the information is added to the network in a passive distributed way without the use of local transmitters. The array topologies used to implement interferometric arrays include serial, ladder, and star type configurations. One of the issues has been the uniformity with which sensor signal can be coupled to the array and transmitted to the receiver system. A second issue commonly faced is the Qptical power budget: in a time-division multiplexed (TDM) array,⁴ the average received power/sensor falls as N³, where N is the total number of sensors. In this paper we describe a system in which large numbers of sensors can be efficiently multiplexed, and demonstrate an array of 64 sensors in a TDM configuration with optical amplifiers for boosting the input power and telemetry over 100 km.

© 1996 Optical Society of America