US Patent 7502120 Fiber optic interferometric sensor array

The invention relates to an apparatus for multiplexing Fiber Optic Interferometric Sensors (FOISs), which apparatus comprises means (1) forming the an optical source for providing m*n distinct wavelengths λ11, λ12, . . . , λ1n, λ21, λ22, . . . , λ2n, . . . , λm1, λm2, . . . , λmn, the optical source including means for generating m groups (111, 112, . . . , 11m) of light pulses, each group 11j (1≦j≦m) being made up of n light pulses Pk(λj1), Pk(λj2), . . . , Pk(λjn) of distinct wavelengths λj1, λj2, . . . , λjn, the n light pulses Pk(λj1), Pk(λj2), . . . , Pk(λjn) being time delayed one from another, Fiber Optic Interferometric Sensors distributed in m groups (51, 52, . . . , 5m) of n sensors each, then sensors of a same group being located at the same point and set into a star like arrangement around the input point of the group, and each of the n sensors of a same group 5j, 1≦j≦m, being associated with wavelength selective means so that it is interrogated by one light pulse only among the pulses Pk(λj1), Pk(λj2), . . . , Pk(λjn) of distinct wavelengths respectively λj1, λj2, . . . , λjn.