The performance and limitation of optically amplified analog links

In this paper, we investigate the performance of EDFA optically amplified analog links using two-tone SFDR (spurious-free dynamic range) measurements. The results show that optical amplifier can improve the link loss budget by more than 20 dB in analog links, which is beneficial to high splitting analog distributing networks, longer distance (10-100 km) analog trunks, and analog optical signaling processing applications. However, optical analog links are more susceptible than digital links to ASE noise and enhanced fiber nonlinear distortion due to amplified optical power. We show that the ASE-beat-signal noise may saturate the SFDR at high input power region. We will then discuss the effects of fiber nonlinearity for single wavelength and multiple wavelength analog links. In this paper, we only focus on the third-order nonlinearity distortion because it is the dominant nonlinearity when the frequency span is within an octave