In the context of short-reach data-center interconnect, such as OIF 400ZR, we study the system impact of bandwidth loss of Silicon Photonics Mach-Zehnder modulators in high-speed coherent modems. As well, we propose a minimum-mean square gradient-descent based method to optimize the compensation of such loss at both transmitter and receiver signal processing finite-impulse response filters. The method improves required-optical signal to noise ratio (ROSNR), under realistic hardware restrictions such as implementation noise and clock jitters at data converters, by 0.5 dB compared to fully pre-compensating the frequency response. Other advantages, such as lower power consumption, are highlighted as well.
In the context of standardized 400ZR, we study the adjacent channel power ratio (ACPR) as a measure for quantifying the impact of pluggables in flexible-grid dense wavelength division multiplexing (DWDM) networks. Using Monte- Carlo simulations, the ACPR is calculated under standardized roll-off factors for a dual-polarization 16QAM channel at 59.8GBaud. The ACPR is shown to adequately represent the impact of linear cross-talk as a function of channel spacing and channel power. From 75GHz (DWDM) to 59GHz (Super-Nyquist) optical transmission, we report a universal approach for specifying the penalties of flexible-grid pluggables on a channel’s required signal-to-noise ratio (SNR) and timing recovery.