Simultaneous Generation of Wired and Wireless Signals Using a DP-MZM in a RoF System

We experimentally demonstrate a simultaneous generation of independent 10-Gbit/s wired on/off keying (OOK) signal and 20-Gbit/s wireless quadrature phase shift keying (QPSK) signal by using a dual-polarization Mach-Zehnder modulator (DP-MZM) in a millimeter-wave-band radio-over-fiber system at 30 GHz. The polarization directions of two signals are orthogonal, so there is not any interference between two polarizations in the photodiode. By using a 100/200-GHz interleaver, the power penalty after 15-km fiber transmission for the wireless QPSK signal can be reduced from 3.9 to 1.9 dB. As we know, this is the first time to use QPSK modulation format for the wireless signal in the simultaneous generation and delivery of wireless and wired signals by using a dual-polarization modulator.