This part of IEC 61291 applies to all commercially available optical amplifiers (OAs) and optically amplified assemblies. It applies to OAs using optically pumped fibres (OFAs based either on rare-earth doped fibres or on the Raman effect), semiconductors (SOAs), and waveguides (POWAs). The object of this standard is: – to establish uniform requirements for transmission, operation, reliability and environmental properties of OAs; – to provide assistance to the purchaser in the selection of consistently high-quality OA products for his particular applications. Parameters specified for OAs are those characterizing the transmission, operation, reliability and environmental properties of the OA seen as a “black box” from a general point of view. In the sectional and detail specifications a subset of these parameters will be specified according to the type and application of the particular OA device or assembly.