An apparatus and method for enabling cost-effective duplex communication
by diplexing one of down stream signals for frequency up-conversion in a
hybrid fiber-radio system includes diplexing an unmodulated mode signal
among beating signals between a master laser and an injection-locked
slave laser and using the diplexed signal for down-conversion in upstream
transmission, thereby eliminating the need for expensive high-frequency
local oscillators for frequency conversion. Higher radio frequency
signals can be generated using beating between basic modes and satellite
modes such as FWM conjugates of the master laser and slave laser.
Cost-effective systems, stabilization of a light source and improved
transmission performance may be achieved by using a diplexer instead of
an expensive high-frequency local oscillator.