Fibre optic anemometry using an optical delay cavity technique

Limitations on the performance and capabilities of conventional fibre optic Doppler Anemometers (FODAs) are highlighted in the context of fluid flow measurement. In order to overcome these difficulties, a novel optical fibre signal processing scheme is outlined, based on a low coherence interferometric approach using an optical delay cavity matched for the position of the required measurement volume. Both a homodyne and a heterodyne system are discussed and experimental results are presented to verify the feasibility of the proposed method.