A 6.2mm² 56.6Gbps 18.2pJ/b oFEC Decoder for Optical Communications

A complete 5-core iteration-unfolded open forward error correction (oFEC) decoder is presented. The <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$6.2 \text{mm}^{2}$</tex> decoder adopts a bit-level parallel architecture with transpose reordering to achieve 56.6 Gbps at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$18.2 \text{pJ} / \mathrm{b}$</tex>, surpassing the state-of-the-art by 2.8 x in throughput, 4.8 x in energy efficiency, and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$6.5 x$</tex> in area efficiency. An efficient list-64 decoding enhances error correction with a pre-FEC BER of up to 2 %.