Figure 7
From: Freely scalable and reconfigurable optical hardware for deep learning
Energy required to transmit 16 bits (communication energy per 8-bit MAC, i.e., \(E_\text {comm}\)). Electronic data transfer energy (\(E_\text {elec}\)) increases with wire length, whereas optical data transfer energy (\(E_\text {DONN}\)) remains constant. Optical data transfer evaluated for two detector capacitances: \(C_\text {det}=1\)Â pF for large, commercially-available photodiodes63; and \(C_\text {det}=0.1\)Â fF for emerging receiverless, (1Â \(\upmu \)m)\(^3\)-sized cubic detectors in modern CMOS processes48. Below \(C_\text {det}=0.1\)Â fF, the capacitance of the overall receiver becomes limited by the capacitance of the CMOS inverter. Otherwise, the capacitance of the photodetector is energy-limiting. Energy of one 8-bit multiply-and-accumulate operation (\(E_\text {MAC} = 25\)Â fJ/MAC) also shown for reference.
