A device testing approach employs optical antennas at test locations of a semiconductor device, usable as either/both radiators or receivers. As a radiator, an antenna responds to localized optical energy at a test location of the device to generate corresponding radiated optical energy that can be sensed and processed by a test system. As a receiver, an antenna receives radiated optical energy as generated by a test system and converts the energy into corresponding localized optical energy for affecting operation of the device. The optical antennas may be formed from metal segments on the same metal layers used for signal interconnections in the device, and thus the disclosed approach can provide enhanced test functionality without burdening the device manufacturing process with additional complexity solely to support testing. The testing approach may be used in different modalities in which the antennas variably act as transmitters, receivers, and reflectors/refractors.