This part IEC 61746 provides procedures for calibrating single-mode optical time domain reflectometers (ODTR). It only covers ODTR measurement errors and uncertainties.
DS/EN 61746-1:2011 history
2011DS/EN 61746-1:2011 Calibration of optical time-domain reflectometers (OTDR) - Part 1: OTDR for single-mode fibres