Carrier frequency offset compensation for 10-Gbaud QPSK RoF transmission at 90 GHz with free-running optical LO signal

We demonstrate W-band (75–110 GHz) RoF radio signal transmission with two free-running lasers using an optical heterodyne technique. The combination of a laser located at a base station for the optical local oscillator and a data-modulated optical signal from a central office provides a W-band radio signal. The carrier frequency offset fluctuation within 6 MHz can be mitigated by digital signal processing at the receiver side, in a similar manner to that of optical digital coherent detection.