Fiber laser sensor hydrophone performance

Distributed feedback fiber lasers (DFB-FL) offer potential as a new generation of sensing devices that are inherently small diameter, very sensitive and which can be interrogated over long distances over extremely thin lead in cables. They also have the advantage of requiring minimal or no electronics and thus have the potential to be very robust and reliable. Thales Australia, in collaboration with Defence Science and Technology Organization - Maritime Operations Division, has undertaken the development of a sea bed hydrophone array using DFB-FL hydrophones as the sensing elements. This paper briefly discusses the theory of operation of the DFB laser and the options for using the DFB-FL as the sensing element in hydrophones. The advantages and disadvantages of various topologies, problems in assembly and measurement solutions are discussed with an overview of the optical processing system.