This paper describes an experimental set-up for detecting electric fields using an electro-optic LiNbO/sub 3/ sensor and coherence modulation of light. In this system, the detected electric field modulates an optical delay, which is introduced by an electro-optic coherence modulator when associated to a low-coherence optical source. The optical delay acts then as the electric field carrier and is transmitted through an optical fiber channel. At the receiver, the electric field is detected by measuring the autocorrelation of the transmitted light using a two-wave interferometer, which is matched to the optical delay in the sensing modulator.