Scott A. Meller

Performance of fiber optic vehicle sensors for highway axle detection

An important part of traffic management and intelligent transportation systems is the availability of cost effective, reliable sensors for vehicle classification and traffic flow monitoring. Fiber optic sensors have numerous advantages over conventional sensors and are thus prime candidates for use in these traffic systems. In this paper, an optical fiber vehicle sensor is described for axle detection. Results from field tests are presented. The performance of the fiber optic vehicle sensor is evaluated and methods of vehicle weight-in-motion are also discussed.

IMPLEMENTATION OF EFPI-BASED OPTICAL-FIBER SENSOR INSTRUMENTATION FOR THE NDE OF CONCRETE STRUCTURES

Abstract This paper reports on the design and implementation of an optical-fiber sensor based on the extrinsic Fabry-Perot interferometer (EFPI) for the non-destructive quantitative evaluation of advanced concrete-based civil structures. The performance of the EFPI sensor is demonstrated in two different applications. In the first implementation, performed with researchers in the Civil Engineering Department at the University of Southern California in Los Angeles, optical-fiber sensors were used to obtain quantitative strain information from reinforced concrete interior and exterior column-to-beam connections. The second implementation, performed in co-operation with researchers at the Turner Fairbanks Federal Highway Administration Center in McLean, Virginia, used optical-fiber sensors, attached to composite prestressing strands used for reinforcing concrete, to obtain absolute strain information. The paper is concluded with a discussion of practical considerations that need to be taken into account when implementing optical-fiber sensors in a concrete civil structure environment.

High-temperature optical fiber sensors for characterization of advanced composite aerospace materials

Optical fiber sensors have numerous advantages over conventional sensing technologies. One such advantage is that optical fiber sensors can operate in high temperature environments. While most conventional electrical-based sensors do not operate reliably over 300 degrees C, fused silica based optical fiber sensors can survive up to 900 degrees C, and sapphire based optical fiber sensors can survive up to 2000 degrees C. Using both fused silica and sapphire technologies, we present result for high temperature strain, pressure, and temperature sensors using Extrinsic Fabry-Perot INterferometric-based and Bragg grating sensors. High temperature strain and temperature sensors were used to conduct fatigue testing of composite coupons at 600 degrees C. The results from these specific high temperature applications are presented along with future applications and directions for these sensors.

Advances in optical fiber sensors for vehicle detection

THe primary objective for this project is the design of optical fiber-based sensor instrumentation for specific ITS applications. Specifically, this paper discusses research on optical fiber sensors that can be used for traffic monitoring and vehicle classification. This paper also discusses developments on the application of optical fiber sensor that can be used for monitoring visibility. This research is directly beneficial to the implementation of driver advisory and safety systems, traffic control system, and other ITS applications. This paper summarizes research performed on optical fiber sensors used for measuring traffic flow on highways and discusses progress on optical fiber sensors used for monitoring visibility.

Development of fiber optic sensors for advanced aircraft testing and control

Optical fiber sensors, because of the small size, low weight, extremely high information carrying capability, immunity to electromagnetic interference, and large operational temperature range, provide numerous advantages over conventional electrically based sensors. This paper presents preliminary results from optical fiber sensor design for monitoring acceleration on aircraft. Flight testing of the final accelerometer design will be conducted on the F-18 Systems Research Aircraft at NASA Dryden Flight Research Center in Edwards, CA.

Optical fiber sensors for vehicle detection

Optical fiber sensors, because of their small size, low weight, extremely high information carrying capability, and immunity to electromagnetic interference, provide numerous advantages over conventional electrically based sensors. Fiber-based sensors has found numerous applications in industry for process control, and more recently for monitoring the health of advanced civil structures. This paper presents an overview of optical fiber sensors for civil structure monitoring and emerging applications of optical fiber sensors for traffic monitoring. Vehicle flow, vehicle speed and weight-in-motion measurements using fiber-based sensors are discussed, and results from field tests are presented to demonstrate the effectiveness of fiber sensors at determining traffic flow.

NDE characterization of advanced composite materials with high temperature optical fiber sensors

Optical fiber sensor have numerous advantages over conventional sensing technologies. One exciting capability of optical fiber sensor is their ability to operate in high temperature environments. While most conventional strain, pressure, etc. sensors do not operate reliably over 300 degrees C, fused silica based optical fiber sensor can survive up to 900 degrees C. High temperature materials such as sapphire and silicon carbide can be used to construct sensors that can survive up to 2000 degrees C. A suite of high temperature strain, pressure, and temperature sensor are being developed using the Extrinsic Fabry-Perot Interferometer technology for NDE characterization of advanced composite materials. These sensors have been demonstrated in several applications. High temperature strain and temperature sensors were used to conduct fatigue testing of composite compounds at 600 degrees C. High temperature pressure senors are being developed as microphones for high temperature acoustic testing. The result from these specific high temperature applications are presented along with future applications and directions for these sensors.

Optical fiber interconnected MEMS sensors and actuators

Microelectromechanical systems or MEMS are miniature devices that have several advantages over conventional sensing and actuating technology. MEMS devices benefit form well developed integrated circuit production methods which ensure high volume, high yield processes that create low-cost sensors and actuators. OPtical fiber interconnected MEMS will provide new functionality in MEMS devices such as multiplexed operation for distributed sensing applications. This paper presents approaches in optical fiber to MEMS interfacing and some preliminary results.

Manufacturing and applications of optical fiber sensors and systems

Optical fiber sensors, because of their small size, low weight, extremely high information carrying capability, immunity to electromagnetic interference, and large operational temperature range, provide numerous advantages over conventional electrically based sensors. Fiber-based sensors have found numerous applications in industry for process control, and more recently for monitoring the health of advanced civil structures. This paper presents preliminary results from optical fiber sensor designs for monitoring acceleration and magnetic field.

Polymer and metal-matrix composite-embedded optical fibers for avionics communication links

Significant weight and space savings have been realized in avionic equipment and structures by using composite materials. Optical fiber provides improved communication between equipment and components on board the aircraft. The marriage of these two technologies by embedding optical fiber in the composites achieves improved signal transmission and reduced weight. The goal of this work is to provide reliable, low-profile, optical interconnects with composite-embedded optical fiber for communication with opto-electronic circuit cards and modules. The design and results of a prototype embedded multimode optical beamsplitter utilizing in-fiber 45 degree(s) dielectric coatings are presented.