The increasing demand for wireless video-based interactive and multimedia data services explains why 60-GHz millimeter-wave wireless system is a promising candidate to provide multi-gigabit-per-second wireless services. While attempting to generate and transmit 60 GHz signals in a wireless system cost effectively and increase the spectral efficiency to facilitate multi-gigabit-per-second services, this work reviews three radio-over-fiber (RoF) systems based on optical frequency multiplication (up to 6 times) to reduce the bandwidth requirement of optical transmitters. Additionally, orthogonal frequency division multiplexing (OFDM) signals with multi-level modulation formats (16 QAM) are utilized to achieve an ultrahigh data rate of 28 Gbps within the 7-GHz license-free band and compensate for an uneven frequency response of 60-GHz RoF systems. Negligible power penalty following 25-km standard single mode fiber (SSMF) transmission is observed, capable of significantly extending the service range to various applications within a building or campus.
- optical frequency multiplication