Powered by the innovation of Bell Labs, Nokia is at the forefront of creating the technologies that are increasingly at the heart of our connected lives. The mission of Bell Labs is to define the future of communications and networking and deliver disruptive innovations that redefine human existence and business realities. Within Bell Labs, the "Optical Systems & Devices Research” lab investigates forward-looking research activities for the preparation of the future optical transport networks that will interconnect data centers, cities and continents. Until recently, such networks were expected to provide ever increasing capacity, flexibility and agility at reduced costs and energy footprint. Lately, a new dimension, security, emerges as a separate, high-priority need. The future optical fabric offers digital services down to the physical network layer by introducing platforms to collect, visualize, analyze, and learn from the collected data. In this direction, a lot of effort has been put into the development of a network digital twin, i.e. a digital representation of the optical network which can be used to understand the optical network evolution in time (i.e. after its deployment), anticipating issues, troubleshooting etc. Digital twin for synchronous optimizations and real-time network healing requires massive monitoring, performance predictions, local and centralized decision-making, machine learning. The digital twin can be instrumental in building a secure and robust fiber infrastructure, enabling new services where the prevention of malevolent incidents and fast recovery is particularly required.