Abstract :
Radio over Fiber is a hybrid technology that combines the technology of optical fiber
with radio waves, with a very high access speed. For the concept of mobile broadband
modulation for optical and wireless to connect i.e. wear on (Orthogonal Frequency
Division Modulation). The performance of the system depends on RoF optical modulator,
modulation and bit rate used power level lasers and fiber optic channels, RF, power level
non liniear optical. Dithering overcome non-linear effects of optical seraat fiber optic, in
there is some type of nonlinear systems this dithering can cope with nonlinear type of SBS
formed by light scattering in an optical fiber, and to lower the frequency of the radio
signal is modulated, and increasing amplitude linearity of the system. On this research
will be conducted on system design-RoF using mapping 4-QAM, the variations of power
input-8 dBm,-6 dBm,-4 dBm,-2 dBm, 0 dBm, 2 4 dBm, dBm 6 dBm, and 8 dBm, fiber
length variation and 10 Km, 50 Km, 100 Km and based on the results of testing that te is
done system use dithering can increase power received on sisireceiver so it makes a
better signal quality, the influence of the input power (dBm) on CW Laser greatly affects
the signal spectrum, a constellation of signals, and also the power received at the
receiver. Systems using dithering showed good results, at the power input on the CW
laser is great, but given the small input power is experiencing a shift phase motors.
Keywords: Radio over Fiber(RoF), OFDM, Dithering, Nonlinear.