Performance of a Multi-Gb/s 60 GHz Radio Over Fiber System Employing a Directly Modulated Optically Injection-Locked VCSEL

A multi-Gb/s 60 GHz radio over fiber (RoF) system employing direct modulation of an optically injection locked vertical-cavity surface-emitting laser is successfully demonstrated. Experimental results show that the RoF system is tolerant to fiber chromatic dispersion due to inherent single-sideband modulation produced by injection locking. A simple carrier-to-sideband equalization method is used to substantially improve the sensitivity of the RoF system by 18 dB, enabling both successful wireless signal transmission and multilevel signal modulation formats such as quadrature phase shift keying (QPSK). At least 3 Gb/s ASK-modulated data and 2 Gb/s QPSK-modulated data is transported over up to 20 km standard single-mode fiber and 3 m wireless distance with no penalty.