One embodiment of the present invention provides a system that
communicates between a first semiconductor die and a second semiconductor
die through optical signaling. During operation, the system converts an
electrical signal into an optical signal using an electrical-to-optical
transducer located on a face of the first semiconductor die, wherein the
first semiconductor die and the second semiconductor die are oriented
face-to-face so that the optical signal generated on the first
semiconductor die shines on the second semiconductor die. Upon receiving
the optical signal on a face of the second semiconductor die, the system
converts the optical signal into a corresponding electrical signal using
an optical-to-electrical transducer located on the face of the second
semiconductor die.