BS PD IEC/TR 61292-9:2017, which is a Technical Report, focuses on semiconductor opticalamplifiers (SOAs), especially the specific features and measurement of gain and polarizationdependent gain (PDG).In this document, only the amplifying application of SOAs is described.Other applications, such as modulation, switching and non-linear functions, are not covered.Potential applications of SOAs, however, such as reflective SOAs (RSOAs) for the seededwavelength division multiplexing passive optical network (WDM-PON), are briefly reviewed inAnnex A.Cross References:IEC 61291-1ITU-T Recommendation G.984.6IEC 61291-2IEC 61290-1IEC TR 61292-3ITU-T Recommendation G.661ITU-T Recommendation G.698.3