Performance of Subsampled Analog Optical Links

We analyze the operation and performance of subsampled analog optical links. These links downconvert microwave signals by optically sampling at a rate much lower than the RF carrier frequency. Expressions for conversion gain, noise figure, and spurious-free dynamic range are derived for intensity modulation and direct detection. The impact of pulse width on link performance is revealed and quantified. Also, in order to characterize noise in a subsampled link, the influence of timing jitter in the periodic optical source is considered. Timing jitter and pulse width are found to be two important factors which limit the noise figure and dynamic range in subsampled links.