DOFS are highly suitable for monitoring temperature, vibration and strain using physical principles such as Raman, Rayleigh and Brillouin backscatter. They convert a standard telecom infrastructure to a sensor network providing 1000s of virtual sensors/km using the intrinsic light/glass interaction during propagation. DOFS have clear benefits in certain space applications, such as the ability to embed the sensors in the structure of reusable vehicles (even for ground testing, where they could remain after testing), the very small size of the sensors and simplified wiring. DOFS could also complement earth observations from space with ground or ocean-based monitoring, e.g. of ocean currents, salinity and temperature to improve climate models. DOFS have wide terrestrial applications, such as the monitoring of energy cables linking offshore wind farms to the mainland. The terrestrial market is about $100M with typical growth of 5-10% per year including some applications that have 20+ years maturity. The issue with present DOFS is that the interrogators (opto-electronic unit that probes the fibre and interprets the optical signal) consist of multiple optical components linked by fibre connections that need careful, bulky, packaging and are vibration-sensitive. This has, so far, rendered them unsuitable for space applications. Each interrogator is also specific in the physics that it addresses, meaning a specialised box for each type of DOFS. This OSIP project will investigate using PICs as the “optical engine” in DOFS with strong benefits in size, cost, vibration tolerance and improved performance. It should also result in a single optical platform that can perform different types of DOFS measurement. This proposal is for a first proof-of-concept including how to apply PIC technology and a practical demonstration. It will test a totally new approach to designing DOFS which will address space applications and new terrestrial markets identified as high volume and low cost.
