Microwave Photonic Link with Carrier Suppression for Increased Dynamic Range

Theoretical analysis and experimental investigation of microwave photonic links with bias-shifted Mach-Zehnder modulators are presented. An optical amplifier is used to increase link gain and reduce noise figure. The combination of modulator bias shift away from quadrature and optical amplification reduces the link noise figure by more than 15 dB. For modulation frequencies from 2 to 18 GHz, the third-order limited spurious-free dynamic range (SFDR3) of these links is greater than 120 dB, normalized to a 1-Hz bandwidth. Conventional links based on Mach-Zehnder modulators are limited to SFDR3 values of approximately 110 dB, normalized to a 1-Hz bandwidth. This level of performance is achieved without electronic or optical linearization.