3.5-Gbit/s QPSK Signal Radio-Over-Fiber Transmission With 60-GHz Integrated Photonic Array-Antenna Beam Forming

This paper studies the performance of 3.5-Gbit/s quadrature phase shift keying (QPSK) signal radio-over-fiber (RoF) transmission with beam forming of array antennas. An “integrated photonic array-antenna (IPA)” is utilized in this experiment, where uni-travelling carrier photodiodes are fully integrated with 60-GHz-band 4 × 2 array-antenna elements into a single board. The beam forming operation for the IPA is experimentally demonstrated by using a QPSK signal assuming real mobile data traffic, and the QPSK signal quality during the beam forming operation for the IPA is quantitatively evaluated. The expandability for more advanced modulation formats, such as 16-quadratic-amplitude modulation, is also studied. In addition, the required system parameters for practical use are shown by investigating the induced transmission penalty. The obtained results enable us to design next generation radio access networks based on 60-GHz RoF transmission technique.