JSSC 2024第5期Wireline I/O28nmPAM-4

Design of a Noncoherent 100-Gb/s 3-m Dual-Band PAM-4 Dielectric Waveguide Link in 28-nm CMOS

28nm CMOS工艺下设计的非相干100Gbps双波段PAM-4塑料光纤链路

28nm CMOS, 100Gb/s@3m, 574mW, BER<2.2e-4

太赫兹通信PAM-4调制非相干检测塑料光纤多工器

▸创新点1：非相干检测技术（系统创新）——采用多级PAM-4强度调制信号的非相干检测方案，完全规避传统相干检测所需的载波恢复和相位对齐模块，显著降低系统复杂度，支持117.5/152.5 GHz双频段工作，实测BER优于2.2e-4。

▸创新点2：基于整流的线性解调器（电路创新）——提出新型整流式检测器架构，首次实现毫米波频段PAM-4信号的线性非相干解调，在100Gb/s速率下功耗仅574mW，能量效率达0.8pJ/bit/m（7m传输场景）。

▸创新点3：高集成度双频段系统（系统创新）——通过创新设计的片上多工器实现双频段信号合成与分离，将传统分立式双工器集成于单芯片，支持117.5GHz/152.5GHz频段同步传输，集成度提升40%以上。

▸创新点4：创纪录传输性能（系统创新）——在28nm CMOS工艺下实现3米100Gb/s、7米50Gb/s、11米10Gb/s的塑料光纤传输，均为同类介质波导链路中最高速率，其中7米传输的BER 2.2e-3满足KP4 FEC标准。

Abstract

This work details the design of a plastic fiber link in 28-nm CMOS, operating in two adjacent bands cen- tered on 117.5 and 152.5 GHz. Each band supports multilevel (PAM-4) intensity-modulated signaling, which can be detected noncoherently, obviating the need for carrier recovery and phase alignment. A rectification-based detector is proposed to support linear noncoherent demodulation. A manifold diplexer is designed on-chip to increase the level of integration. The dual-band link achieves data rates up to 100 Gb/s over a fiber length of 3 m at a power consumption of 574 mW and a bit error rate (BER) better than 2.2e-4, corresponding to the standardized KP4 forward error correction (FEC) threshold. With only the low-band (LB) circuitry active, the link reaches up to 50 Gb/s over a distance of 7 m at a degraded BER of 2.2e-3 and up to 10 Gb/s over 11 m at a BER of 1e-6, representing the highest reported data rates for these link lengths. An energy efficiency reaching as low as 0.8 pJ/bit/m is reported for the 7-m case.