A Spectral-Efficient Self-Homodyne-Detected Microwave Photonic Link With an Extended Fiber-Reach

In this letter, a simple and spectral-efficient self-homodyne-detected microwave photonic link is proposed and experimentally demonstrated. At the transmitter, a phase-modulated optical signal and an intensity-modulated optical local oscillator signal are polarization-multiplexed and delivered in a single fiber over long distance. At the receiver, the two signals are coherently detected by a self-homodyne interferometer and then demodulated through simple digital signal processing. The proposed scheme is experimentally validated by 25-km fiber transmission of the 50-Msymbol/s 16-QAM microwave vector signals at 2 and 2.5 GHz. The transmission performance compared with the conventional homodyne detection scheme in terms of error vector magnitude and bit error rate is evaluated. The proposed scheme can be a potential solution to wireless access networks for both high spectral efficiency and low-cost implementation.