Next Article in Journal
Dancing Salsa with Machines—Filling the Gap of Dancing Learning Solutions
Next Article in Special Issue
Design and Implementation of a Novel Measuring Scheme for Fiber Interferometer Based Sensors
Previous Article in Journal
Impact Localisation in Composite Plates of Different Stiffness Impactors under Simulated Environmental and Operational Conditions
Previous Article in Special Issue
Dynamic Deformation Reconstruction of Variable Section WING with Fiber Bragg Grating Sensors
Open AccessArticle

Nonlinearity Correction in OFDR System Using a Zero-Crossing Detection-Based Clock and Self-Reference

by Shiyuan Zhao 1,2, Jiwen Cui 1,2,* and Jiubin Tan 1,2
1
Center of Ultra-Precision Optoelectronic Instrument, Harbin Institute of Technology, Harbin 150080, China
2
Key Lab of Ultra-Precision Intelligent Instrumentation, Harbin Institute of Technology, Ministry of Industry and Information Technology, Harbin 150080, China
*
Author to whom correspondence should be addressed.
Sensors 2019, 19(17), 3660; https://doi.org/10.3390/s19173660
Received: 30 July 2019 / Revised: 20 August 2019 / Accepted: 20 August 2019 / Published: 22 August 2019
(This article belongs to the Special Issue Fiber Optic Sensors and Applications)
Tuning nonlinearity of the laser is the main source of deterioration of the spatial resolution in optical frequency-domain reflectometry (OFDR) system. In this paper, we develop methods for tuning nonlinearity correction in an OFDR system from the aspect of data acquisition and post-processing. An external clock based on a zero-crossing detection is researched and implemented using a customized circuit. Equal-spacing frequency sampling is, therefore, achieved in real-time. The zero-crossing detection for the beating frequency of 20 MHz is achieved. The maximum sensing distance can reach the same length of the auxiliary interferometer. Moreover, a nonlinearity correction method based on the self-reference method is proposed. The auxiliary interferometer is no longer necessary in this scheme. The tuning information of the laser is extracted by a strong reflectivity point at the end of the measured fiber. The tuning information is then used to resample the raw signal, and the nonlinearity correction can be achieved. The spatial resolution test and the distributed strain measurement test were both performed based on this nonlinearity correction method. The results validated the feasibility of the proposed method. This method reduces the hardware and data burden for the system and has potential value for system integration and miniaturization. View Full-Text
Keywords: optical fibers; Rayleigh scattering; optical frequency-domain reflectometry; strain measurement optical fibers; Rayleigh scattering; optical frequency-domain reflectometry; strain measurement
Show Figures

Figure 1

MDPI and ACS Style

Zhao, S.; Cui, J.; Tan, J. Nonlinearity Correction in OFDR System Using a Zero-Crossing Detection-Based Clock and Self-Reference. Sensors 2019, 19, 3660.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop