The role of photonic and electronic gain in the design of analog optical links

The loss of coax, even moderately high frequencies, can be so high as to rule out many important applications. Lower loss means RF transmission exist, such as waveguides, but the size and weight of such options severely restrict the applications. In this paper, the authors review the conditions under which an optical link can achieve positive gain, as measured by the available power gain. This paper also reviews the link design factors that permit the link to have low noise figure and show that there is a fundamental dependence link gain and noise figure.