Abstract: Disclosed is an RF transceiver including a receiver chain performing a dual conversion with respect to a received RF signal, thereby generating an IF signal; a chain of transceiver performing a dual conversion with respect to an IF signal to be transmitted, thereby generating an RF signal; and an IF SAW filter used in the receiver chain and the transmitter chain in common, the IF SAW removing an unnecessary signal generated during a first down-conversion after an IF signal having undergone the first down-conversion is IF-amplified in the receiver chain, and removing an unnecessary signal generated during a first up-conversion after an IF signal having undergone the first up-conversion is IF-amplified in the transmitter chain.

Abstract: A phase optimization apparatus and method to obtain a maximum extinction ratio by feeding back a portion of an optical signal output from a Mach-Zehnder interferometer wavelength converter using XPM of a semiconductor optical amplifier to maintain an optimum phase difference between two arms. The phase optimization apparatus includes a first arm having a first semiconductor optical amplifier that amplifies a pump signal and a probe signal, a second arm having a second semiconductor optical amplifier that amplifies the probe signal, and a ? phase shifter that controls the phase of the amplified signal, an optical band-pass filter that filters optical signals to output only the modulated probe signal; and a phase control unit that receives feedback to output to the ? phase shifter of the second arm a phase control signal, which controls a phase difference between the first and second arms.

Abstract: Disclosed relates to a wavelength division multiplexing-passive optical network (WDM-PON) system that can lock wavelengths of upstream light signals output from a plurality of optical network units (ONUs) by using coherent multi-wavelength light sources and reduce mode partition noises caused when using the coherent multi-wavelength light sources.