Highly robust and hardware-efficient frame synchronization and carrier recovery via pilot-only approaches for short-reach optical interconnections

We propose a cost-effective scheme relying exclusively on pilot symbols for robust frame synchronization and high-precision, wide-range carrier recovery in short-reach optical interconnects. Our method mitigates phase offsets and enhances phase tracking by strategically placing dual-polarization pilot symbols, both aligned and misaligned, within the frame. Compared to traditional carrier recovery schemes, our approach offers a broader frequency offset estimation range, higher carrier recovery accuracy, and significantly lower computational complexity. Experimental results show a 0.7 dB sensitivity improvement at the soft decision forward error correction threshold, outperforming Fourier transform-based frequency offset estimation combined with blind phase search.