An optical measurement apparatus (102) containing a bidirectional optical transceiver component (200), the bidirectonal optical transceiver component (200) comprising a source of optical electromagnetic radiation (208), an optical detector (214), a beamsplitter, and a combined input and output port (218). The port (218) is arranged to permit, when in use, propagation of optical electromagnetic radiation therethrough. The beamsplitter is aligned within a housing (206) with respect to the optical source (208), the optical detector (214) and the port (218) in order to direct optical electromagnetic radiation emitted by the optical source (214) to the port (214) and to direct optical electromagnetic radiation received from the port (214) to the optical detector (208).