Optical transducer array system

Abstract

An array of optical waveguide transducers, especially suitable for use in a multi-channel hydrophone seismic streamer, contains optical waveguides which are deformed in response to the parameter being sensed (underwater acoustic energy in the case of the seismic streamer). Two optical signals are obtained from each transducer, amplitude modulated in opposite polarity in accordance with the parameter and returned to a collection point by way of optical signal highways, such as optical fiber waveguides. The optical signals are time division multiplexed on the return highways by successively providing light pulses to each of the transducers upon activation of separate light sources associated therewith which are electrically activated by electrical signals propagated along a transmission line wherein the electrical signals are successively delayed. The optical signals on the return waveguides appear in time slots corresponding to the successive delays and may be sequentially interrogated at a rate compatible with the frequency response of the array system. At the collection point, the outputs of the return waveguides are subtracted thereby summing the optical signals from each transducer, while reducing noise introduced into the system as may be due both to variations in the amplitude of the light from the sources and mechanically due to deformation or bending of the optical waveguides other than in response to the parameter being sensed.