A \boldsymbol \times \boldsymbol-\mathbf/\mathbf PAM-4 Silicon-Photonic Transceiver Front-End for Linear-Drive Co-Packaged Optics

• Published in: 2023 IEEE Asian Solid-State Circuits Conference (A-SSCC) pp. 1 - 3
• Main Authors: Liu, Han, Qi, Nan, Lu, Donglai, Dong, Zizheng, Zhang, Zhihan, He, Jian, Li, Guike, Li, Leliang, Liu, Ye, Dang, Ziyue, Chen, Daigao, Zhang, Zhao, Liu, Jian, Wu, Nanjian, Xiao, Xi, Liu, Liyuan
• Format: Conference Proceeding
• Language: English
• Published: IEEE 05.11.2023
• Subjects: Optical fiber amplifiers; Optical interconnections; Optical losses; Optical switches; Power demand; Stimulated emission; Transceivers
• DOI: 10.1109/A-SSCC58667.2023.10347914

The explosive growth of the data-intensive AI computing demands for datacenter interconnects with ever-increasing bandwidth (BW). Traditional pluggable optical modules can hardly meet the DC power and form-factor requirements by the new 51.2T ethernet switch. By tightly integrating the compact optical engine (OE) into the switch package, on-board metal traces are mostly replaced by optical fiber, which thereby saves the signaling power and improves the front-panel BW-density. Depicted in Fig. 1(a), each 3.2T OE employs 4 quad-lane optical transceivers (O-TRX) in the package, enabling 16\times 112\ \text{Gb}/\mathrm{s} fiber channels directly attached to the chip edge. Meanwhile, the pluggable optical module has to employ a power-hungry DSP-based O-TRX to compensate for the channel-loss beyond 100 Gb/s per lane. The integrated co-packaged optics (CPO) in contrast, simplifies the transceiver by replacing the DSP with linear driver and amplifier with embedded continuous-time linear equalizers (CTLE). The so-called linear-drive (LD) CPO draws increasing attentions, since it significantly reduces power consumption, cost, and latency. The embedded CTLE needs to equalize 10-12 dB channel loss between the switch and each OE.