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

This work details the design of a plastic fiber link in 28-nm CMOS, operating in two adjacent bands centered 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.