Noise Reduction in Class-AB Microwave-Photonic Links

A Class-AB microwave-photonic link is presented as a means to reduce noise associated with DC-bias. By operating with two complementary, approximately half-wave-rectified, optical sources and generating the difference in a balanced detector, linear modulation with high modulation efficiency is achieved with near zero DC. Using two mode-converter intensity modulators, we demonstrate a 5 dB reduction in shot noise and elimination of intensity noise, relative to a quadrature-biased Mach-Zehnder, for the same received RF signal power.