The radio-over-fiber (ROF) link is of much interest to
provide broadband wireless access. In this paper, we discuss some
characteristics of a directly modulated ROF link in CDMA and FDMA environments.
These RF measurement results show that, though the ROF link has adequate bandwidth
to support several radio channels, nonlinear distortion and power loss, mainly
due to electrical to optical conversion process and vice versa, limit the
performance. Especially, the AM-PM type nonlinearity that starts at low power
levels is a bigger concern. Furthermore, the spurious free dynamic range (SFDR)
decreases because the increases with the bandwidth of the RF signal.