A Distributed Fibre Temperature Sensor Using The Optical Kerr Effect

The paper reports on the feasibility of measuring temperature distribution in optical fibres using the optical Kerr effect. The basis of the proposed method is to inject a pump pulse into one arm of an optical fibre interferometer to cause a transient phase imbalance as a result of the optical Kerr effect. As the optical pulse and the interferometer interogating beams propagate in opposite directions, the magnitude of the optical Kerr effect as a function of distance along the fibre can be determined from the temporal variation of the detected signal. The results show that the temperature dependence of the optical Kerr effect appears to be substantially less than that reported for the electrical Kerr coefficients measured at low frequencies.