A novel demodulation scheme for the ranging of reflective markers is presented. This method is useful for implementing in-line multiplexing of displacement and temperature sensors based on lowcoherence interferometry. It allows the discrimination of reflective markers such as air-gap connectors or other partial reflectors spaced by as little as 0.1 m and the measurement of deformations occurring between two successive reflectors with a resolution of 2 ?m. The multiplexing of two displacement sensors is demonstrated experimentally. This type of sensor is especially useful for the long-time geometrical monitoring of large structures.