800G/λ Self-Homodyne Coherent Links With Simplified DSP for Next-Generation Intra-Data Centers

Assuming a low-latency forward error correction (FEC)-based bit-error-rate (BER) threshold, we demonstrate and provide a detailed analysis of a 120 Gbaud/DP-16QAM single-carrier self-homodyne coherent link in the C-band. Through theoretical and simulation analysis as well as experimental investigation, we find that a minimum receiver DSP based on a simple I-Q correction scheme is needed to compensate for the combined effect of fiber dispersion, I-Q phase rotation, transmitter I-Q impairment, and receiver skew in combination with a finite analog to digital converter (ADC) resolution. Based on the simplified DSP, we demonstrate link budgets of 4.5 dB (for 16 amplified dense wavelength division multiplexing (DWDM) channels) and 5.2 dB (unamplified single-channel case). The amplified DWDM self-homodyne coherent system provides a 12.8 Tb/s capacity per fiber pair and is useful for bandwidth-demanding intra-data center applications.