Optical encryption for high-bit rate systems using fiber Bragg gratings

A technique for encrypting optical communication signals using fiber Bragg gratings is proposed and demonstrated. The input pulses were converted into two pulses by differential delay imposed by the reflection on two Bragg grating with different spectral response and separated along the fiber. To recover the original pulses, a similar but inverted grating arrangement is used. The principle has been tested with a periodic pulse train of 1.4 GHz repetition rate.