In one embodiment, an apparatus comprising an optical transmitter, having an optical transmitter portion and an electrical transmitter portion, and configured to convert an electrical signal to an optical signal, and transmit the optical signal; an optical receiver, having an optical receiver portion and an electrical receiver portion, configured to receive an optical signal and convert the optical signal to an electrical signal; a passive power controller configured to passively detect whether or not a cable is coupled with the optical transmitter and, if not, to place at least the optical transmitter portion in a sleep mode.