Crosstalk analysis of the in-line quasi-distributed low-coherence low-finesse Fabry–Pérot fiber-optic interferometric sensors

• A crosstalk analysis of the quasi-distributed Fabry-Pérot fiber-optic sensors is presented.
• The appropriate selection of the cavity lengths eliminates the second-order intermodulations.
• Only the third-order intermodulations can significantly influence the sensors crosstalk.
• For a reflection coefficient lower than 0.5%, the signal-to-intermodulation ratio is higher than 26 dB.

A crosstalk analysis of the in-line quasi-distributed low-coherence low-finesse Fabry–Pérot fiber-optic interferometric sensors is presented in this paper. The appropriate selection of the sensor cavity lengths eliminates the presence of the second-order intermodulations. Therefore, the intermodulations that can significantly influence the sensors crosstalk are the third-order intermodulations. For a typical sensor configuration by choosing the in-fiber mirror reflection coefficient lower than 0.5%, the minimum achievable signal-to-intermodulation ratio is higher than 26 dB for a maximal possible number of sensor placed along the fiber that satisfies broad range of requirements for most of the quasi-distributed measurements of typical parameters such as strain and temperature.