Abstract

Erbium-doped fiber amplifiers (EDFAs) are an attractive means to increase the distribution capabilities of a single DFB laser in AMVSB TV systems. While linearity is extremely important in such systems, reports in the literature concerning EDFA linearity in multiple channel systems offer conflicting results ranging from no detectable change in composite second-order distortion (CSO)¹ due to the slow gain dynamics of EDFAs,² to significant observed degradation of CSO attributed to a combination of signal laser chirp and variation of EDFA gain with wavelength.³ In this paper we present conclusive results from measurements of EDFAs which show significant degradation of CSO, and indicate that the relevant mechanism is from the interaction of wavelength chirp on the signal and spectral variation of the EDFA transmission.

© 1992 Optical Society of America