Sensor array and method of selective interferometric sensing by use of

Abstract

A sensor array and method for remotely monitoring environmental effects on a selected sensor. In a sensor array comprising a plurality of interferometers, an optical signal of a selected configuration is provided so that portions of the optical signal are propagated through the interferometers. The optical signal configuration causes optical signal portions which have traveled the same signal path, except where separated on signal paths in a selected interferometer, to coherently mix when combined at an output of the selected interferometer. No other optical signal portions in the sensor array will coherently mix. The optical signal comprises plural components such as side bands which are configured to form a power spectrum defining an optical signal coherence function having a maximum which repeats periodically at a rate substantially corresponding to optical signal travel time difference in the selected interferometer. Also, the coherence function has minimums or zero values at times such that intervals between various minimums substantially correspond to optical signal travel time differences through non-selected interferometers, thus precluding coherent mixing of optical signal portions emerging from those non-selected interferometers. By modifying characteristics of the optical signal components, one may change the repetition period of the coherence function maximum and of selected coherence function minimums to produce coherent mixing of signal portions from another interferometer while precluding coherent mixing of signals from all other interferometers, including the previously selected interferometer. Accordingly, a given sensor may be selected from monitoring, to the exclusion of all others.