STTR Phase II: Active Fiber Optic Sensor Array for Cryogenic Fuel Monitoring and Management

This Small Business Technology Transfer (STTR) Phase II project will develop a multi-functional active fiber Bragg grating sensor technology for the monitoring and management of cryogenic fuel such as liquid hydrogen and liquefied natural gas. The proposed technology uses in-fiber light to actively adjust sensor temperature, which will drastically improve responsivity and sensitivity of fiber sensors in the cryogenic environment. By coating fiber Bragg grating sensors with functional films, liquid fuel levels, spatial distribution, hydrogen concentration, and temperature can be simultaneously measured at cryogenic temperatures. Active sensors to be developed in this program are immune to electromagnetic interference and can be multiplexed in a single fiber, which allows a one-fiber and one-fiber-feedthrough solution for the cryogenic fuel management on the ground and in space. The broader impact/commercial potential of this project will be the development of a prudent sensing technology and system to improve the safety and reliability of the use of both liquid hydrogen and liquefied natural gas fuels. As major alternative fuels to power the U.S. economy for decades to come, they share a high economic value that requires accurate and reliable metering and management. Having a flexible, multi-use system available that can be installed with absolute confidence to monitor and manage these fuels, as well as the health of installed systems, will have a major impact on the acceptance of these volatile fuels as safe alternative energy sources. The ability to multiplex many sensors on a single fiber will enable safer and more economical penetrations in cryogenic walls and the low corrosion potential of the fibers will enable sensors to be placed along piping underground. The same basic active fiber sensor technology has the potential to be extended to fuel flow and other economically useful functions.