Apparatus for optical communications (10, 20, 30, 60 90) includes an optically switched resonant tunneling device (12, 22, 42, 62, 92) being exposed to an input light. The optically switched resonant tunneling device (12, 22, 42, 62, 92) generates a first and second voltage levels in response to the intensity level of the input light. A lasing device (16, 28, 46, 68, 74, 100) is coupled to the optically switched resonant tunneling device (12, 22, 42, 62, 92). The lasing device (16, 28, 46, 68, 74, 100) generates and modulates an output light in response to the first and second voltage levels.