A datacenter interconnect (DCI) is a connection between data centers and between the components within them. The goal of a data center interconnect is to provide high bandwidth in order to maximize the utility of the data center. Inter data center interconnects must also be able to transmit over long distances. By using specialized infrastructure such as optical communication and direct connection between datacenters, DCI is able to provide much higher bandwidths than typical networks. This is valuable to large cloud computing companies. In 2017, IEEE standards were created to support 400 GbE per wavelength optical communications. For short range connections within a data center, optical DCI can provide the advantage over traditional DCI of not needing cables.
Modern data center interconnects rely heavily on optical fiber communication technologies to achieve high capacity and long-distance transmission. Single-mode fiber is commonly used due to its low attenuation and ability to transmit signals over hundreds or thousands of kilometers. A key technology in DCI is Dense Wavelength Division Multiplexing (DWDM), which allows multiple data channels to be transmitted simultaneously over a single fiber by using different wavelengths of light. Combined with coherent optical transmission techniques and optical amplifiers, DWDM systems can support data rates of 400 Gbit/s and beyond per wavelength, depending on system design.
Latency is a critical factor in data center interconnect performance and is primarily influenced by physical distance and transmission medium. Data transmitted over optical fiber travels at approximately two-thirds the speed of light, resulting in increasing delay over longer distances. For example, intercontinental connections between regions such as Europe, North America, and Asia introduce significantly higher latency compared to regional connections. However, latency is not strictly proportional to distance, as network routing, switching, and infrastructure optimization can affect overall transmission time. To reduce latency, operators often deploy direct fiber routes and private interconnections between data centers.
Hyperscale cloud providers such as Google, Amazon, and Microsoft play an increasingly important role in data center interconnect (DCI) infrastructure. These companies operate large-scale global networks that connect multiple data centers across regions using high-capacity optical fiber links. In addition to relying on traditional telecommunications providers, hyperscalers increasingly invest in and build their own backbone infrastructure, including terrestrial fiber networks and submarine cables. This allows them to achieve lower latency, higher reliability, and greater control over data traffic. As a result, private network interconnection has become a key component of modern DCI architectures.
Recent developments in data center interconnect (DCI) are strongly driven by the rapid growth of artificial intelligence (AI), cloud computing, and global data traffic. Modern DCI infrastructures increasingly adopt high-capacity optical technologies such as 400G and 800G transmission, with emerging research focusing on 1.6 terabit (1.6T) systems and beyond. These higher data rates are necessary to support large-scale distributed AI workloads, which often span multiple data centers across regions.
At the same time, DCI has become one of the fastest-growing segments of network infrastructure due to increasing demand for high-speed connectivity between data centers. Optical transport technologies such as DWDM are evolving to support higher capacity, improved energy efficiency, and better scalability, making them a critical component of modern computing systems. In addition, new approaches such as silicon photonics and co-packaged optics are being developed to further increase performance and reduce power consumption.
Another important trend is the integration of AI into network management and operation. Modern DCI networks increasingly rely on automation and intelligent control systems to optimize routing, reduce latency, and improve reliability. As data center infrastructures continue to expand globally, DCI is evolving from a simple transport mechanism into a strategic foundation for distributed computing and digital services.