Time-division multiplexing of large serial fiber-optic Bragg grating sensor arrays.

Time-division multiplexing is a promising method for the interrogation of fiber-optic Bragg grating sensors arrays for measurement of strain and temperature. We examine the performance of these systems to determine the parameters for high-sensitivity, low-cross-talk operation. It is shown that the performance can be greatly improved by use of a short time resolution in the demultiplexing process. We propose a new method of demultiplexing with an electro-optic modulator to read out the sensor pulses by gating the signal with 400-ps resolution. The system is demonstrated experimentally to provide 0.15-microepsilon/square root(Hz) strain resolution in a 50-Hz bandwidth within a full-scale range of 8000 microepsilon. The system parameters are capable of handling at least 50 time-addressed sensors on a single fiber.