IEC TR 61282-16:2022 is a technical report on coherent optical receiver and transmitter technologies that are employed in fibre optic communication systems as well as in optical test and measurement equipment. This document describes the principle of operation and functional capabilities of coherent optical receivers as well as the operation of optical transmitters used to generate complex vector-modulated signals. It is intended to serve as a technical foundation for other IEC documents and standards related to coherent optical transmission techniques.