Interrogation of fibre-optic interferometric sensors using acousto-optic tunable filter

A new technique for the interrogation of interferometric-based fibre-optic sensors using an acousto-optic tunable filter (AOTF) is demonstrated The scheme involves frequency shift keying (FSK) of the RF drive to the AOTF to track the shift of a single fringe peak from an interferometric sensor. Experimental results are presented for a Fizeau interferometer. The technique provides high accuracy, plus a large unambiguous tracking range free from interruptions