Google takes the lead in applying multi-core optical fiber to submarine cable systems

Global digital acceleration has led to an exponential increase in bandwidth demand, necessitating the expansion of submarine fiber optic cables for bandwidth transmission between continents. Therefore, in collaboration with industry partners, we have been continuously seeking innovative methods to enable each cable to accommodate more bandwidth, enhancing network resilience and capacity for cloud service providers and network operators. Today, we will delve into one of the latest innovations in submarine fiber optic cables: Multi-Core Fiber (MCF) technology.

Firstly, let's briefly discuss the history. Traditional submarine fiber optic cables receive power from the shore, and as data is transmitted along the cable, a set of dedicated pump lasers amplify the light signals for each fiber pair. Recent advancements in Space Division Multiplexing (SDM) technology increase the number of fibers within the cable, allowing submarine cable systems to meet growing demands, thereby providing higher total capacity at a more cost-effective rate per bit.

However, current SDM technology is beginning to face scalability challenges. Increasing the number of fibers within the cable without enlarging its outer diameter is proving difficult, requiring more materials and resulting in increased weight, which poses a burden on maritime operations and maintenance. Additionally, adding more fibers means significantly longer manufacturing, testing, and repair times.

Multi-Core Fiber (MCF) represents an evolution of single-core fiber, built upon the foundation of single-core fibers that rely on a circular glass core surrounded by a glass cladding. With MCF, the number of cores within the cladding is doubled, allowing it to transmit more light and information at a lower cost per bit. All of this is achieved within the same fiber! This means that with an equivalent number of cores, using MCF technology reduces the number of fibers required, thereby accelerating manufacturing, testing, and making maintenance more convenient.

Currently, Google and NEC are collaborating to adopt Multi-Core Fiber (MCF) technology in constructing a new submarine cable system, marking the first instance of its application in the submarine cable industry.

Eduardo Mateo, NEC's Director of Technology Strategy, stated, "The implementation of MCF for the first time in a submarine network represents an important milestone toward the next-generation systems, offering greater capacity, more efficient connectivity, and lower cost per bit."

Over the past decade, Google and NEC have closely collaborated to advance industry-changing submarine cable technologies, and we take great pride in recently introducing MCF into a brand new submarine cable system. As single-core fibers evolve into MCF, we look forward to witnessing the emergence of a supply chain ecosystem capable of providing MCF functionalities for the entire industry.

With the ever-growing demand for online content, cloud services, and AI applications, we anticipate that multi-core fibers will become an integral part of the global telecommunications infrastructure. This represents an exciting new direction for expanding submarine cable capacity, paving the way for increasing the number of cores per fiber to meet the industry's bandwidth requirements further.