Related Experiment Video
Updated: Jun 19, 2026
08:23
A Random-displacement Measurement by Combining a Magnetic Scale and Two Fiber Bragg Gratings
Published on: September 30, 2019
Simultaneous interrogation of interferometric and Bragg grating sensors.
Optics Letters
|October 28, 2009
Summary
This study introduces a novel method for simultaneously measuring strain with Bragg grating sensors and displacement with Fizeau interferometers. The technique achieves high resolution for both sensor types using a single low-coherence source.
Area of Science:
- Optics and Photonics
- Sensor Technology
- Metrology
Background:
- Interferometric sensors and fiber Bragg grating (FBG) sensors are crucial for precise measurements.
- Simultaneous interrogation of different sensor types often requires complex setups or multiple light sources.
- Achieving high phase and strain resolution is critical for advanced applications.
Purpose of the Study:
- To develop a novel method for simultaneous interrogation of two-beam interferometers and Bragg grating sensors.
- To utilize a single low-coherence source for enhanced sensor performance and system simplification.
- To achieve high phase resolution for interferometric sensors and high dynamic strain resolution for grating sensors.
Main Methods:
- Employing an unbalanced Mach-Zehnder interferometer illuminated by a low-coherence source.
- Configuring the interferometer to act as a wavelength-tunable source for the Bragg grating.
- Utilizing the interferometer as a path-matched filter for a Fizeau interferometer.
Main Results:
- Demonstrated a dynamic strain resolution of approximately 0.05 microepsilon/sqrt(Hz) at 20 Hz for the grating sensor.
- Achieved an interferometric phase resolution better than 1 mrad/sqrt(Hz) at 20 Hz.
- Corresponded to an root-mean-square (RMS) mirror displacement resolution of 0.08 nm.
Conclusions:
- The proposed method enables simultaneous, high-resolution interrogation of interferometric and grating sensors.
- The use of a single low-coherence source simplifies the system while enhancing measurement capabilities.
- This technique offers a promising approach for advanced sensing applications requiring combined displacement and strain measurements.
Related Concept Videos
02:18Interference and Diffraction
Interference is a characteristic phenomenon exhibited by waves. When two electromagnetic waves interact with their peaks and troughs coinciding, a resulting wave with enhanced amplitude is produced. This is known as constructive interference. In this case, the two waves interacting are in phase with each other.
01:25IR Spectrometers
There are two main infrared (IR) spectrophotometers: dispersive IR spectrometers and Fourier transform infrared (FTIR) spectrometers. In a dispersive IR spectrometer, a beam of infrared radiation produced by a hot wire is divided into two parallel equal-intensity beams using mirrors. One beam passes through the sample, while another is a reference beam. The beams then move through the monochromator, which separates the radiations into a continuous spectrum of different frequencies. The...