Most commercialized fiber optic sensors operate at temperatures between -40 and 150 C. Higher temperatures can degrade polyimide fiber coatings (above 250 C) and erase FBGs from the fiber core (above 400 C).

Some industrial applications (e.g., oil refining, steel production and chemical formulation) require much higher temperatures, and often conventional thermocouples do not last long enough or do not operate reliably due to high EMI or cumbersome cabling.

Several research organizations and commercial companies are working to develop high temperature optical sensors that are both accurate and reliable in high temperature environments. One such company is Chiral Photonics, Inc. in Pine Brook, New Jersey. They recently announced a novel optical sensor that uses twisted fibers to create a thermally sensitive spectral response. The sensor appears to be stable, accurate and repeatable at temperatures up to 1000 C.

Find details at: www.chiralphotonics.com/

Now that the optical core is nicely characterized, Chiral is working on ruggedized packaging for large-scale field deployments. Sensor readings are made simple with self-contained laser instrumentation and software from Micron Optics — so the user does not need optical systems expertise to use these sensors. They are as easy to use as conventional sensors.