IEC 61290-4-4:2018 applies to optical amplifiers (OAs) and optically amplified elementary sub-systems. More specifically, it applies to OAs using active fibres (optical fibre amplifiers, OFAs) containing rare-earth dopants, such as erbium doped fibre amplifiers (EDFAs), presently commercially available, as indicated in IEC 61291-1. This document provides the general background for optical amplifier gain transients and their measurements and indicates those IEC standard test methods for accurate and reliable measurements of the following transient parameters:
a) optical input power increase/decrease transient gain overshoot and transient net gain overshoot;
b) optical input power increase/decrease transient gain undershoot and transient net gain undershoot;
c) optical input power increase/decrease gain offset;
d) optical input power increase/decrease transient gain response constant (settling time).
These parameters have been included to provide a complete description of the transient behaviour of gain controlled OA. The parameters defined here are applicable if the amplifier is an OFA or an alternative type of OA.
Keywords: optical amplifiers (OAs) gain transients