Nokia’s industrial research lab

For the past 100 years, Bell Labs has turned imagination into real-world innovations that have transformed communication, computing, and connectivity. Their researchers pioneered breakthroughs like transistors, lasers, and digital communications, changing everyday life. Today, as Nokia’s industrial research lab, they continue to innovate responsibly, creating sustainable technologies with meaningful impact on society.

Turning Optical Fibers into Guardians Against Network Failures

Nokia Bell Labs scientists are developing innovative optical sensing techniques aimed at transforming conventional optical fibers into environmental monitoring systems, enabling early warning detection of potential network failures. Beyond telecommunications, optical sensing could have far-reaching implications, providing environmental monitoring that would be helpful in measuring climate change in terms of temperature shifts and ocean current swells, as well as in detecting earthquakes…

Bell Labs is pioneering “coherent MIMO (Multiple Input Multiple Output) sensing” techniques for optical fibers by integrating dual-polarization optical interrogation into distributed sensing systems. This method uses continuous light probing over multiple orthogonal polarization channels, making the sensing process resistant to polarization fading, which is a common source of error and sensitivity loss in traditional single-polarization optical sensors. By translating advances from high-capacity optical communications into distributed sensing, Bell Labs is enabling large-scale, long-range monitoring applications using the existing telecommunications fiber infrastructure.

Results on “Coherent MIMO-DFS using Stabilized lasers” at OFC25

Scientists from Nokia Bell Labs recently demonstrated that sensing can be performed over distances beyond 100 km over standard single mode fibers and over ultra-low loss hollow core fibers. At OFC Conference 2025 in San Francisco, they showed that tailored laser stabilization enables MIMO-DFS to perform distributed acoustic sensing on fiber distances over 100 km (see figure).

“Demonstration of MIMO-DFS over 100 km of unamplified SSMF Link using Active Laser Drift Stabilization and Optimized Probing Codes”, Presentation at OFC25

During the same conference, they also showed for the first time Coherent DFS over ultra-low loss hollow core fibers, achieving ultra-high resolution HCF characterization and acoustic sensing (“High-Resolution Coherent DFS Over 20km Ultra-Low-Loss Anti-Resonant Hollow-Core Fiber with Live Traffic” Presentation at OFC25 Post deadline session).

Advancing Coherent MIMO for Real-World Fiber Sensing through SENSEI

Bell Labs team plans to develop new techniques to improve coherent MIMO technology in collaboration with SENSEI partners. They will then thoroughly evaluate these fiber sensing methods for both environmental monitoring and network health monitoring in real-world conditions using different types of fiber optic cables over an extended period. This long-term testing will help identify and classify various types of events that affect the cables. Bell Labs’ approach addresses two main limitations of previous studies:

1. Past experiments were usually short-term and isolated, using either unused or specially installed cables
2. Traditional sensing methods generate large volumes of data rendering longer tests impractical

This extended testing period will present new challenges, particularly in managing and analyzing vast amounts of data. The teams will need to develop effective ways to process this information, especially since established models for the patterns they expect to observe do not yet exist, and the data may contain significant background noise.

Bell lab’s team at Paris-Saclay, France