A safe-mode OTDR method for characterizing an optical fiber link is provided, as well as an OTDR apparatus operating under such a safe mode. The method includes performing OTDR acquisitions along the fiber link using an OTDR apparatus connected at a proximal end of the optical fiber link, and operating under OTDR acquisition conditions that have been deemed safe for a communication device at a distal end of the fiber link. The obtained reflectometric trace, representing a proximal portion of the optical fiber link, is used to determine a partial-link loss value associated with the proximal portion of the fiber link. Modified acquisition conditions that are safe for the communication device are determined based on the partial-link loss value and on loss-related maximum rating parameters for the communication device. The process is repeated using the modified OTDR acquisition conditions until the end of the link has been reached.