Data Rate Quadrupled Coherent Microwave Photonic Link

A data rate quadrupled microwave photonic link (MPL) based on coherent detection and digital signal processing (DSP) is proposed and experimentally demonstrated. The data rate is quadrupled by employing both intensity and phase modulation and polarization multiplexing to transmit four microwave vector signals with an identical microwave center frequency over a single optical carrier. The recovery of the four microwave signals is implemented at a coherent receiver followed by DSP with a new algorithm, to separate the four microwave vector signals and to eliminate the phase noise from the transmitter and local oscillator laser sources and to cancel the unstable frequency offset between the two laser sources. Error-free transmission of four 2.5-Gpbs 16-QAM microwave vector signals with a total data rate of 10 Gbps if forward error correction (FEC) is employed. The total net data rate is 9.225 Gbps if the zero padding and the FEC (overhead 6.7%) are considered. The use of the proposed MPL for the implementation of $4\times 4$ MIMO is also discussed.