Fully-Integrated Silicon RF Distributed Amplifier Linearization

Driven by the demand of low-cost base stations deployment and enhanced micro-cellular coverage and capacity, Radio-over-fiber (RoF) has attracted much research attention as a convenient way to distribute RF signals to base stations and to subscribers. In RoF systems, a highly-linear optical transmitter is necessary to achieve the required signal dynamic range. Fully-integrated design techniques are required to address linearity improvements for RoF transceivers. Nonlinearities in wireless communications are responsible for a phenomena that degrades system's performance and must be minimized. A major design challenge for broadband amplifiers is the stringent linearity requirement over a wide bandwidth range, nonlinearities cause harmonics and unwanted intermodulation products which degenerate the transceiver performance. An ideal amplifier should have a linear relationship between the input and output signal. However this is not the case in a practical amplifier. As the input signal power level increases, this relationship becomes non-linear and causes distortion in the output signal. External linearization circuitry can be added to the amplifier to compensate for the non-linearity.