Multiplexing topology combining frequency and time division for fiber optic interferometric sensors

A variety of techniques for multiplexing fibre optic interferometric sensors (FOIS) have been described in the literature [1]. For large numbers of sensors the topology known as the matrix-array [21 using frequency division multiplexing (FDM) is attractive despite the fact that the multiplexing gain is lower than networks exploiting time division multiplexing (TDM) as it allows large numbers of sensors to be multiplexed.