Why LIOS sensing?

NKT Photonics is the market leader in distributed optical sensing of temperature and strain. Backed by more than 20 years of experience and thousands of systems in the field, we deliver LIOS monitoring solutions with unrivaled quality and performance. We provide full solutions from the early design phase, over installation and commissioning, to service and maintenance when the system is deployed. Everything made in Germany with full ISO 9001 and 14001 certification.

Advantages of the LIOS sensing technology

The LIOS temperature and strain monitoring solutions from NKT Photonics are based on using passive optical fibers as distributed sensors, whereby we can deliver continuous and accurate monitoring of temperature and strain over long distances or large surfaces. The LIOS systems are not only the safest solution but also the most cost-effective for large installations.


Unlike many traditional solutions, the LIOS sensing systems are immune to vibration, electromagnetic noise, dust, cryogenic temperatures, and moisture so no matter the challenge, our robust fiber optic sensor can withstand it.  The LIOS sensing systems are installed Worldwide in critical applications like fire detection in road and rail tunnels, special hazardous buildings, power cable and aerial transmission line monitoring, in oil & gas exploration, and for industrial induction furnaces surveillance.


Our LIOS product series was carefully designed and thoroughly tested targeting reliable performance and accurate temperature monitoring over long distances or large areas in industrial environments. Excellent Mean-time-between-failures (MTBF) of more than 30 years was obtained based on the latest statistical field analysis of our LIOS product series.

The Distributed Temperature Sensing OFDR technology – with its approved optical components from the telecom industry – enables to provide sophisticated fibre optic temperature surveillance at commodity prices. The applied light source is a modern and durable semiconductor laser diode, instead of a rather complex solid state laser, which powers typically Raman OTDR system.

The semiconductor laser diode has been critically type tested according the Telcordia GR-468 standard and is fulfilling telecom standards with a medium lifetime of > 25 years. Not only the laser diode has been tested, the entire system was comprehensively evaluated by various independent international bodies (e.g. the Germany VdS, the association of German asset insurers), which includes EMI tests as well as endurance tests at accelerated aging environments.


  • Robust Industrial design
  • Widespread use of Telcordia tested components ensures high reliability (MTBF in excess of 30 years)
  • Fan-free design with passive cooling; no moving parts -> Maintenance free
  • Full turn-Key solution with installation
  • ATEX/IECEx certified
  • Full monitoring solutions with advanced visualization software
  • Integrated communication with third party equipment
  • Full temperature profile available
  • Easy commissioning and self-diagnostics
  • High level of automation in installation (wizards and self-scanning)
  • Laser product class 1M according to DIN EN 60825-1:2007 means the system is safe to install and operate even in the event of cable break
  • No integrated Windows PC for better data security and higher reliability
  • Encrypted communication available for all
  • Two Ethernet ports for two different domains (also for redundant communication)
  • Single-ended detection with no loop-back needed (we can offer loop-back if requested)