preferred polarization state if the optical modulator 22 is sensitive to the polarization of the optical signal the polarization control may be performed by inducing birefringence into the optical fiber after the fiber splitter 16 or by other methods known in the art referring to fig2 bragg grating sensor array 18 includes several bragg gratings 30 a 30 b 30 n are written at separate locations in the single mode optical fiber 14 optical pulse 13 from light source 12 containing sufficient optical bandwidth to cover the expected range of bragg wavelengths of any given bragg grating sensor in array 18 is launched into the serial sensor array 18 through the optical coupler 16 the bragg grating sensors 30 are each fabricated to be reflective within the bandwidth of the optical source and wavelength measurement capability of the system for any reasonable perturbations of the sensors the reflectivity of each bragg grating sensor in array 18 at each of their respective bragg wavelengths is designed to be a few percent or less so that only a small portion of the pulse 13 launched into the array is back reflected at each sensor the rest of the optical pulse is allowed to propagate to sensors further down the array 18 and be likewise reflected the arrows 32 indicate the possible paths of the optical signal thus from the single optical pulse 13 launched into the sensor array 18 a train of pulses 36 are returned from the sensor array through the fiber path 38 after passing through coupler 16 each returned pulse has a spectral content corresponding to the spectral reflectivity of the bragg grating.