ECOC 2023 unfolds as a vibrant showcase, sparking discussions on various fronts. Advancements in 800G and 1.6T optical devices, linearly driven pluggable optics (LPO), co-packaged optical devices, and optical input/output (I/O) interfaces, among others, mark significant progress. Participants engage in lively debates concerning artificial intelligence and the future trajectory of the optical communications industry.

Reflecting on ECOC, a fundamental theme emerges: the debate between serial and parallel transmission. While serial remains the ideal method, the purpose of parallel design is to enhance serial transmission, thereby simplifying parallel design. However, this becomes increasingly challenging over time.

Progress is evident in enabling 224G electrical signals, yet the longevity of 112G electrical channels remains uncertain. Despite achieving a 200GBd baud rate in coherent optics, the duration before further baud rate growth depends on factors like design type (pluggable or embedded) and network deployment.

Addressing the optimal expansion of optical I/O and managing fiber quantity poses another challenge. Bandwidth density and fiber management issues affect parallel systems, particularly in compute clusters employing thousands of GPUs for large model training. The debate also encompasses fiber utilization across E, S, C, and L bands versus parallel fiber cores and multimode fibers.

Linearly driven pluggable optics shine at ECOC, building upon the momentum from the OFC exhibition in March.

Cambridge Technology showcases the most extensive LPO test dataset to date. Their demonstration of transmitter tuning programs compensating for copper wire signal distortion raises questions about streamlining module testing on switch panels. Tuning modules on switch panels could potentially simplify testing during production, further reducing LPO costs.

Disparities in LPO performance among switches from different vendors are evident. Challenges persist in optimizing switch designs for LPO, especially concerning 200G line rates. While data on the next stage of LPO (1.6T modules at 8x200G) is pending, initial results may emerge next year.

Though optical module suppliers express enthusiasm for LPO prospects, no end-users have confirmed deployment plans. While NVIDIA deploys these modules internally in AI clusters, comments on offering LPO-equipped systems to end-users are pending. With LPO modules offering significant power savings, adoption may commence next year, potentially impacting market forecasts.

NewPhotonics unveils a silicon photonics chip compatible with DSP-based pluggable modules or LPO. Their chip, working with Credo's Dove 8x106Gb/s PAM4 DSP IC, sends 224Gb/s optical channel signals by modulating two electrical channels. Demonstrating functionality without DSP, their technology enables 224Gb/s transmission over 12km single-mode fiber using Intel SerDes signals. NewPhotonics aims to scale this technology to 3.2Tb/s, supporting 200Gb/s and higher LPO rates.

Their chip, employing time-division multiplexing for signal modulation and transmission, introduces a method for generating parallel channels. At the receiver, signals are unpacked and processed using optical signal processing to recover data.