Performance and power consumption of digital signal processing based transceivers for optical interconnect applications

We discuss the suitability of digital signal processing (DSP) and optical orthogonal frequency division multiplexing (OFDM) for optical interconnects in applications such as data centers and high performance computing. The performance and power dissipation of this technology is reviewed and compared with single carrier binary modulation formats used in parallel fiber and wavelength division multiplexed interconnects. The paper considers the power consumption of the individual sub-systems of an OFDM link, including FFT cores, data converters (DAC, ADC) and forward error correction circuits. The dependence of the error vector magnitude (EVM) on the DAC/ADC resolution is calculated for a 1024 channel 16-QAM OFDM link, and the implications for the design of the OFDM optical interconnects in terms of minimising the power consumption are discussed.