Modulation fading in temporal Talbot effect

Temporal Talbot phenomenon is the time-domain counterpart of the well-known spatial Talbot phenomenon, which can be used to compress/expand input pulses or multiply the pulse repetition rate. It is of great interest to study the temporal Talbot effect with modulation due to its potential applications in information transmission, in which the envelope of the input pulse sequence is modulated by a signal. In this letter, we report the modulation fading phenomenon in the temporal Talbot effect, i. e. the phenomenon that the modulation depth degrades with the increase of the order of the Talbot effect, for the first time to our knowledge. Distinct from the attenuation caused by the fiber loss, the modulation fading relates to the pulse width, the repetition period of the pulse sequence, and the frequency of the modulating signal as well as the order of the Talbot effect. A fully analytical expression of the modulation transfer function is presented to explain this phenomenon. Potential application of the modulation fading in temporal cloaking is discussed.