OPTICAL TRANSCEIVER BUILT-IN TEST (BIT)

An optical transceiver is provided with a light pipe that intercepts, offsets and redirects a portion of the collimated transmit beam to create a virtual object in the receiver field-of-view to perform the BIT. The light pipe comprises an input face and first reflective surface in the transmitter FOV to intercept a portion of the beam along a first axis and re-direct the beam, a second reflective surface and output face in the receiver FOV that re-directs the portion of the beam along a second axis towards the receiver to create the virtual object in the receiver FOV and an optical channel that guides the redirected portion of the beam from the first reflective surface to the second reflective surface to offset the second axis from the first axis. The same detector used during normal operation of the transceiver is used to perform the BIT, which may include a simple on/off test or a radiometry test. The light pipe may be designed with an acceptance FOV that preserves collimation, which facilitates a measurement of alignment error between the transmit beam and receiver.