Research breakthrough in data centre interconnects

Data centres are designed to store, process and distribute vast amounts of data and applications. From ensuring data availability to supporting scalability, disaster recovery and maintaining robust security measures, data centres play a critical role in enabling the functioning of the modern interconnected digital landscape.

At the heart of data centre operations lie data centre interconnects, the networking infrastructure responsible for facilitating communication between various components within and across data centres. Digital-to-analog converters (DACs) are vital components within these interconnects, tasked with converting digital signals into analog signals for transmission over copper cables. However, the requirement for high-resolution DACs can pose a significant bottleneck due to the associated increase in costs of optical modules.

To address this challenge, researchers have presented a solution that combines a look-up-table-based nonlinear predistortion technique with digital resolution enhancement. This approach, reported in Advanced Photonics Nexus, aims to alleviate the limitations imposed by high-resolution DACs while maintaining efficient data transfer and communication within data centre interconnects.

The proposed technique has yielded remarkable experimental results; by employing look-up-table-based predistortion to mitigate nonlinear impairment, and digital resolution enhancement to reduce the demand for DAC resolution, the researchers have achieved exceptional data transmission performance.

The digital signal processing technique enabled the transmission of signals at rates exceeding 124 GBd PAM-4/6 and 112 GBd PAM-8 over 2 km of standard singlemode fibre using 3/3.5/4-bit DACs. It also facilitated the transmission of 124 GBd PAM-2/3/4 signals over 40 km of standard singlemode fibre using 1.5/2/3-bit DACs. These results represent an advancement in data centre interconnect technology, demonstrating the feasibility of supporting the next generation of Ethernet links targeting speeds of up to 800 GbE or potentially even 1.6 TbE.

Beyond enhancing data centre interconnects, these advancements could also transform various applications across 6G access networks and passive optical networks. By overcoming the challenges associated with high-resolution DACs, this innovative approach also paves the way for more efficient data transmission.

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