Luna to Present Papers at the SPIE Defense + Commercial Sensing Conference

Luna Innovations will take part in two paper presentations at the SPIE Defense + Commercial Sensing Conference this week at the Baltimore Convention Center. “Distributed polarization state sensing with optical frequency domain reflectometry” will be presented 11:20-11:40 am Tuesday, April 16. Optical Frequency Domain Reflectometry (OFDR) is notable for its ability to characterize a fiber distributed reflection profile with high spatial resolution and high sensitivity in a single laser sweep, allowing for the measurement of strain and temperature with millimeter spatial resolution over short ranges (tens of meters up to a few kilometers). The paper investigates how spatially resolved characterization of the polarization properties of light reflected or transmitted by a fiber can enable additional sensing capabilities, including distributed polarization mode dispersion and polarization extinction measurements, with applications in distributed pressure, electric field and transverse stress sensing.

“Single-mode sapphire fiber optic distributed sensing for extreme environments” will be presented 9:50-10:10 a.m. Thursday, April 18. The authors have developed a single-mode sapphire sensor for distributed temperature and flow measurement to address the extreme environments encountered in energy applications. The sensor is designed to also detect and localize fouling and deposits that accumulate on its surface over time. Optical Frequency Domain Reflectometry (OFDR) was employed to yield these distributed measurements.

Temperature accuracy was on the order of 5°C for measurements ranging from room temperature to over 1000°C. Spatial resolution of 11 mm was attained and enabled visualization of the temperature gradients along a fiber passing through a furnace. The effects of cooling flow were characterized for steady operation. Dynamic cooling flow tests showed that the presence of simulated deposits on the outside of the sensor resulted in slower time response in the vicinity of the deposit. This technique could be used to determine the presence and location of deposits along the length of the sensor assembly.