High performance microwave photonic links using double sideband suppressed carrier modulation and balanced coherent heterodyne detection

Abstract

Optical transmission of microwave signals offers many advantages such as increased bandwidth; immunity to electromagnetic interference; reduction of size, weight and power consumption; and low, frequency-independent loss over long distances. But microwave photonic links often lack the performance required to replace traditional microwave links. We present a microwave photonic link architecture that enables high gain and dynamic range, low noise figure, and multi-octave bandwidth operation. Our method uses double sideband suppressed carrier modulation together with a balanced coherent heterodyne detection scheme. The modulation method increases link linearity by producing amplitude modulation based on the optical field rather than intensity. The combination of carrier suppression, optical amplification, phase-locked local oscillator insertion, and balanced detection provide high signal-efficient gain, reduced intermodulation distortion, wide-band operation, and low link noise. The resulting link places this microwave photonic approach in the same performance realm as state-of-the-art microwave links.