RF Power Conversion Efficiency of Photodiodes Driven by Mach–Zehnder Modulators

A comprehensive analysis supported by experimental results is provided for RF and microwave power conversion efficiency (PCE) of photodiodes driven by optical signals with either shaped or pure sinusoidal intensity-envelopes where the shaping is performed with a Mach-Zehnder modulator (MZM). It is shown that optical envelope-shaping provides a significantly improved maximum theoretical PCE of 67% as compared to 50% for sinusoidal intensity-envelopes. Practical PCEs of 40.5%-53.5% have been achieved as compared to previously published efficiencies in the 32%-41% range. The results demonstrate that high-current photodiodes can be used as efficient wideband high-power output stages in microwave photonic distribution systems leading to less complex and more efficient antenna array backplanes.