Sensitive fieldable photoelastic fiber-optic hydrophone

A multimode fiber-optic intensity-modulated hydrophone has been constructed that appears capable not only of matching the sensitivity of conventional hydrophones but in fact has the potential for deployment at ocean depths and the potential for surviving severe hydrostatic shocks. This approach uses a transduction element comprised of a channel of photoelastic material that becomes optically birefringent when subjected to a uniaxial stress. The birefringence in turn acts cooperatively with polarizers to modulate the light beam traveling through the material in a manner that is in accordance with the applied acoustic stress signal.