Optical fiber distance sensor

Project Sponsor: NSF CMS-0528681

Project Description: Optical fiber sensors have been widely exploited for displacement measurement, temperature sensing, medical diagnosis, and confocal microscopy, due to their compact size, light weight, remote operation, capability to operate in harsh environment, and immunity to electro-magnetic interference. Among different measurement schemes, distance measurement is one of the most common and widely applied techniques that often serve as the basis for the sensing of other physical parameters such as pressure, strain, vibration, and acceleration. Optical fiber whitelight interferometers for distance measurement have attracted a lot of attentions recently because they offer ultrahigh accuracy, large dynamic range, and robustness. We are developing an in-fiber whitelight Michelson interferometer using long period fiber grating for absolute distance measurement. The advantages of the proposed distance sensor include ultra-precise absolute distance measurement, large dynamic range, simultaneous distance and temperature measurement, and self-calibrated high-speed data interrogation.  Development of an efficient signal processing technique for data processing is underway. Initial simulation results demonstrate that the signal processing algorithm is able to converge to the absolute distances with sub-nanometer accuracy over a large range. We are interested in applying this novel distance sensor for near-field surface profiling of nanoscale structures and mechanical testing of MEMS thin film materials. In addition, it could have broad applications for damage detection of composite materials, real-time monitoring of manufacturing processes, and in-situ measurement of crack-tip plasticity.

Publications:

Huang, H., Majumdar, A., Cho, J., "Fabrication and evaluation of hybrid silica/polymer optical fiber sensors for large strain measurement", accepted to Trans. Inst. measurement and Control, Intelligent Fault Diagnosis & Prognosis for Engineering Systems Special issue

Majumdar, A. & Huang, H., 2008, “Development of an in-fiber whitelight interferometric distance sensor for absolute measurement of arbitrary small distances”, Applied Optics, v47, n15, p2821-2828 PDF

Huang, H. & Majumdar, A., "Fabrication and evaluation of a LPFG-based whitelight interferometric distance sensor", SPIE-Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, San Diego, CA, March, 2007

Huang, H., “Fabrication and evaluation of hybrid silica/polymer optical fiber sensors for large strain measurement”, SPIE-Smart Structures and Materials and NDE for Health Monitoring and Diagnostics, San Diego, CA, March, 2007

Huang, H., "Data interrogation for Fabry-Perot whitelight interferometry", SPIE-Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, San Diego, CA, February, 2006     PDF

With gratitude and recognition to our fine sponsors: