Fiber-optic millimeter-wave generation at 64 GHz and spectral efficient data transmission for mobile communications

The optical generation and transmission of millimeter-waves is promising for future cellular broadband mobile communication systems operating at frequencies up to 60 GHz. These systems comprise millimeter-wave components for the radio link between the mobile station (MS) and the base station (BS). Optical components are used in the BS and the control station (CS) for the broadband, low-loss connection and for generating millimeter-wave signals. The costs of the numerous BSs should be kept as low as possible. Therefore the generation and control of the millimeter-wave signals should be carried out remotely in the CS, thus obviating the need for millimeter-wave oscillators and modulators in the numerous BSs. In the experimental setup an optical transmitter contained two DFB lasers, depicted as signal laser (LDS), and as reference laser (LDR). Their optical output signals were heterodyned using an optic/millimeter-wave converter in the BS. The lasers were stabilized by sideband injection locking. The master laser (LDM) was modulated by a 3.2-GHz signal via its injection current. LDS and LDR were injection locked to -10th and +10th modulation sidebands.