Project No: FE0001127
Performer: University of Cincinnati

Robert Romanosky
Advanced Research
Technology Manager
National Energy Technology Laboratory
3610 Collins Ferry Road
P.O. Box 880 PO3D
Morgantown, WV 26507-0880

Susan Maley
Project Manager
National Energy Technology Laboratory
3610 Collins Ferry Road
P.O. Box 880 P03D
Morgantown, WV 26507-0880

Hai Xiao
Principal Investigator
Missouri University of Science and
219 Emerson Hall
Rolla, MO 65409

Award Date:  10/01/2009
Project Date:  09/30/2014

DOE Share: $1,013,796.00
Performer Share: $264,211.00
Total Award Value: $1,278,007.00

Performer website: University of Cincinnati -

Crosscutting Research - Plant Optimization Technologies

Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High Temperature and Dynamic Gas Pressure in Harsh Environments

Project Description

The focus of this project is to conduct fundamental and applied research leading to the successful development and demonstration of robust, multiplexed, micro-structured sensors that use single-crystal sapphire fibers. At the core of this technology are hybrid extrinsic/intrinsic Fabry-Perot interferometer (HEIFPI) sensors directly micromachined on a sapphire fiber using an ultrafast laser. This hair-thin, cylindrical filament made of single-crystal sapphire is able to transmit light by confining it within regions of different optical indices of refraction. These sensors can be deployed into the hot zones of advanced power and fuel systems (such as inside a coal gasifier or gas turbine system) with the goal of simultaneously measuring temperature (up to 1600 degrees Celsius [°C]) and dynamic gas pressure.

Program Background and Project Benefits

Securing a sustainable energy economy by developing affordable and clean energy from coal and other fossil fuels is central to the mission of the U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL). To further this mission, NETL funds research and development of novel sensors that can function under the extreme operating conditions often found in advanced power systems.

The use of optical fibers has made a significant impact on sensing technology for use in harsh environments. Optical fibers are ideal for applications that require hightemperature and -pressure measurements because they are more sensitive to the parameters being measured. An optical fiber sensing system is composed of a light source, an optical waveguide (the optical fiber), a sensing element or transducer, and a detector. The transducer modulates some parameter of the light traveling inside the optical fiber (e.g., intensity, wavelength, polarization, or phase) and the system measures the changes in the optical signal received at the detector.

Under the Advanced Research program at NETL, a multidisciplinary research team led by Missouri University of Science and Technology, with members from the University of Cincinnati, is working to meet the challenge of designing, fabricating, integrating, and applying sensing technologies for use in harsh environments.

The sapphire sensors developed in this project will help produce affordable, clean energy from coal and other fossil fuels and contribute to a sustainable energy economy. Advanced process controls facilitated by robust optical fiber sensors will contribute to high efficiency, high reliability, and high environmental performance of existing and future advanced power and fuel systems. Specifically, these sensors will permit gasification plants to produce power from various fuels cleanly and efficiently, supporting the DOE’s goals to increase the availability of power from domestic fuels and decrease the negative environmental effects of coal-fired power production.


Researchers met their initial milestone of constructing models of the HEIFPI sensor in response to anticipated temperature and pressure conditions. Researchers then established structural parameters of the HEIFPI sensor to guide device fabrication. The team has completed a unique sensor fabrication device using a femtosecond laser. Using this device, the team has been able to micro machine sapphire for the purposes of temperature and pressure measurement. In addition, the team has made progress on formulations of thin ceramic films to coat the sapphire. The research team also participated in sensor design and packaging for in situ monitoring of high-temperature synthesis gas in a small-scale coal gasifier at the University of Cincinnati. The experience of testing in harsh environment benefits the research on sensors that are viable for commercial applications.