Dual Purpose of Submarine Cables: Unlocking Potential of the Ocean Floor

Thursday - May 25 2023, 12:06 UTC - 1 year ago

Submarine cables have become a lifeline of global communication, connecting the world. Scientists are now exploring the possibility of utilizing them to serve a dual purpose: using advanced sensors to detect seismic activity, temperature changes, and more. Interesting Engineering talked to Brian Lavallée of Ciena to explore the concept in more details. Elements for the construction of these cables include optical transmission technology, specialized optical amplifiers, surge protection devices and fiber-glass strengthened cables.

In today\'s interconnected world, submarine cables have become the lifelines of global communication, carrying an astonishing 99 percent of intercontinental traffic. These cables span vast distances through one of our planet\'s harshest environments—the ocean floor. However, scientists are now exploring an intriguing possibility: harnessing the unique position of these cables to serve a dual purpose .

By equipping them with advanced sensors, submarine cables can become like nerve endings in the deep sea, capable of transmitting data and predicting seismic activity, monitoring temperature changes, and much more. As this groundbreaking endeavor is still in its early stages, Interesting Engineering (IE) reached out to Brian Lavallée of Ciena, a company at the forefront of technology that underpins the infrastructure of deep-sea cables and satellite systems .

During an insightful Q&A session with Lavallée, we explored the complexity of this concept, aiming to uncover a clearer understanding of its potential and what could lie ahead for its future. The following Q&A session has been lightly edited for flow.Please briefly introduce yourself/your company, and highlight the technology you use that underpins deep sea cable and satellite infrastructure .

My name is Brian Lavallée, and I\'m a senior director at Ciena, a global networking systems, services, and software provider that builds networks that adapt to address ever-increasing bandwidth demands from humans and machines for richer, more connected digital experiences for users worldwide. One of the goals of Ciena and me personally is to bridge the world\'s Digital Divide so that anyone in any country can benefit from high-speed internet .

We\'re seeing a rise in Low-Earth Orbit (LEO) satellite services complementary to existing terrestrial and cellular networks, helping provide high-performance connectivity to traditionally underserved areas. Our technology helps bridge the gap between satellites, undersea telecom cables, and earth-based Points of Presence (POP), where these technologies mesh together to form a global, holistic network .

Based on your professional experience, how might undersea cables that sense seismic activity work, and what technology would be involved in their construction?We already monitor the polarization states within fiber-optic cables to ensure error-free transmission, which can be used to monitor small undersea perturbations. Submarine cables use optical transmission technology to send information between endpoints, such as landing stations, central offices, and data centers .

Data is transmitted down an optical fiber core using an electromagnetic transverse wave with an electric field and magnetic field tightly coupled and perpendicular to each other. The "polarization state" refers to the oscillation direction of the electric field. Under normal conditions, the polarization states are relatively stable. These states are detected by coherent optical modems using advanced Digital Signal Processing (DSP) algorithms and used to ensure data is properly decoded at receivers, resulting in errorless transmission .

The detection of the slightest variations in these polarization states can help predict seismic activity, as well as monitor temperature changes in ocean depths. To support advanced sensing in cable systems, submarine cables must be outfitted with specialized optical amplifiers along the cable route. This enables us to detect, measure, and collect various types of data from the environment, such as sound waves, pressure changes, temperature, and even oxygen levels .

This data can be used to monitor environmental activities and build other deep ocean eco-system related models. Cable systems also need to be able to sense the power transferred from shore stations to onshore repeaters, and optical fiber cables must be able to conduct up to 65000 volts of electricity without causing any damage to them. To safeguard such cable systems, they need to be outfitted with surge protection devices (SPDs) .

These devices act as a line of defense in case of any sudden voltage surge.Finally, submarine cables must be well-equipped and durable enough to withstand the extreme pressure of the underwater environment. Fiber glass is typically used to strengthen the cable and protect it from underwater pressure, as well as insulated metal and/or plastic sheaths for electrical containment.