This part of IEC 61292@ which is a Technical Report@ focuses on semiconductor optical amplifiers (SOAs)@ especially the specific features and measurement of gain and polarization dependent 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 seeded wavelength division multiplexing passive optical network (WDM-PON)@ are briefly reviewed in Annex A.