The major analogue intensity modulation schemes are assessed and compared in relation to their ability to provide high-quality transmission of high-definition television (HDTV) signals on single-mode optical fibre. The practical investigation and novel implementations for subcarrier frequency modulation (SCFM) and square wave frequency modulation (SWFM) schemes are then described prior to discussion of the relative performance attributes of these transmission systems. Both modulation techniques proved satisfactory for high-quality HDTV transmission over single-mode fibre with the balance of the measured performance and the necessary system requirements not decisively favouring either method.