Reconfigurable Envelope Generation of Optical Pulse Train Based on Discrete Fourier Transform

We experimentally demonstrate a fiber-based reconfigurable system for programming the envelope of high-speed optical pulse train by using fractional-rate multilevel amplitude modulation. Amplitude-modulated optical pulse trains undergo the discrete Fourier transform (DFT) realized by the temporal Talbot effect in a dispersive fiber. Consequently, rate-multiplied optical pulse trains with programmable envelopes can be achieved. In this letter, we report experimental synthesis of ~80-GHz optical pulse trains with expectant binary patterns, parabolic, square, and triangular envelopes. We also consider practical implementation issues and numerically analyze the influence from the deviation of modulation coefficients and finite extinction ratio of the Mach-Zehnder modulator on the generated pulses.