Abstract: A device for use in the testing of an optical probe which has at least one optical transmitter/receiver pair composed of one optical transmitter for emitting optical energy along a first path and one optical receiver for receiving optical energy propagated along a second path, the device including: a housing (4,6) formed to be mechanically coupled with the probe and having at least one pair of passages (14), with each passage (14) extending along a respective one of the first and second paths; and at least one optical energy reflecting member (18) disposed in the housing (4,6) and positioned relative to the passages (14) of the pair such that, when the housing (4,6) is coupled to the probe, light propagated along the first path from the transmitter is reflected by the reflecting member (18) into the second path toward the receiver.