An apparatus comprises a laser emitter configured to transmit laser energy across an air gap to a separate device, and a driver circuit electrically coupled to the laser emitter and to an electrical interface. The driver circuit is configured to detect voltage levels at the electrical interface including a first voltage level, a second voltage level, and a third voltage level, and drive the laser emitter at a first power level when detecting the first voltage level, drive the laser emitter at a second power level when detecting the second voltage level, and drive the laser emitter at a third power level intermediate the first and second power levels when detecting the third voltage level.