Time-division multiplexing of interferometric fiber sensors using passive phase-generated carrier interrogation

The multiplexing and demodulation of interferometric sensors using a time-division/phase-generated carrier approach is described. The scheme uses slightly unbalanced interferometers and laser frequency modulation to effect the interrogation of the sensors, while the time-division multiplexing allows individual sensors to be addressed. Phase sensitivities of ~20 microrad/ radicalHz and cross-talk levels of <-47 dB are demonstrated for a three-sensor network.