Full-duplex hybrid FTTH and RoF transport system based on polarization modulators

This work demonstrates a full-duplex hybrid fiber-to-the-home (FTTH) and radio-over-fiber (RoF) transport system to transmit one wired signal and two wireless signals based on polarization modulation techniques. Here, the generated odd-order and even-order sidebands of polarization modulated signals can be colorlessly separated with the help of polarization beam splitters. This system has less interference among the wired signal, microwave and millimeter-wave signals. The uplink design is done by reusing the optical carrier and transmitting it through a single mode fiber (SMF) to the central office. The system is simulated using Orthogonal Frequency Division Multiplexing (OFDM) with 4-Quadrature Amplitude Modulation (QAM) as input. Frequency doubling and quadrupling is also used, such that optical microwave at 7.5 GHz and millimeter-wave at 15 GHz are generated successfully using polarization modulators by directly applying 3.75 GHz signal. This system is proved to have error-free transmissions, open eye diagrams, and clear constellation diagrams.