Frequency-agile vector signal generation based on optical frequency comb and pre-coding

In this paper, we experimentally demonstrate the generation of frequency-agile vector signals based on an optical frequency comb (OFC) and unbalanced pre-coding technology by employing a dual-driven Mach-Zehnder Modulator (DD-MZM) and an intensity modulator (IM). The OFC is generated by the DD-MZM and sent to the IM as a carrier. The IM is driven by a 5 GHz 2 Gbaud quadrature phase-shift keying (QPSK) vector signal with unbalanced pre-coding. The −1st order sideband of one OFC line and the +1st order sideband of another OFC line are selected by a programmable pulse shaper (PPS), after square-low photodiode detection, the frequency-agile vector signal can be obtained. The results show that the 2 Gbaud QPSK vector signals at 30 GHz, 50 GHz, 70 GHz and 90 GHz can be generated by only pre-coding once. It is possible to achieve a bit-error-rate (BER) below 1e-3 for wireless transmissions over 0.5 m using this method. (paper)