are in place to expand into rural zones along rail lines, and in new residential and commercial construction spaces. It is believed China will be the leading user of the technology and this will bring down the cost of equipment. Implementations Several simulation tools can be used to design RoF systems. Popular commercial tools have been developed by Optiwave Systems Inc. and VPIphotonics. The Very Large Array in New Mexico was one of the first RF systems to switch to using fiber instead of coax and waveguides. References Fiber optics Radio technology