Recently, fiber Bragg gratings (FBGs) have played significant roles in a variety of fields such as optical communication, dimensional metrology, buildings health monitoring, ultrasonic waves and vibration measurement, petrochemical and other harsh/remote environments owing to their excellent performances like electromagnetic insensitivity, high accuracy and long term stability. In general, FBGs-based sensors are usually decoupled by detecting the variations of FBGs’ central wavelength, wherein, the accuracy and dynamic characteristics of the FBGs-based sensing are directly dependent on the spectral resolutions and response speed of the interrogation method. However, conventional spectral interrogation methods, which directly utilize an optical spectrum analyzer (OSA) with low resolutions and response speeds cannot satisfy the requirements of detecting small and dynamic variations of the FBGs’ central wavelength accurately. It is therefore of significance to find a FBGs interrogation method with high resolution and high response speed. In this paper, a high resolution and response speed interrogation method based on reflective-matched Fiber Bragg Gratings scheme is investigated in detail. The nonlinear problem of the reflective-matched FBGs sensing interrogation scheme is solved by establishing and optimizing the mathematical model. A mechanical adjustment to optimize the interrogation method by tuning the central wavelength of the reference FBG is investigated to improve the stability and antitemperature perturbation performance. To satisfy the measuring requirement of the optical and electric signal processing, an acquisition circuit board is well-designed, and experiments on the performance of the interrogation method are carried out. Experimental results indicate that the optical power resolution of the acquisition circuit border is better than 8 pW, and the stability of the interrogation method with the mechanical adjustment can reach 0.06%. Moreover, the linearity of the interrogation method is 3.3% in the measurable range of 60 pm; the influence of temperature is significantly reduced to 9.5%; the wavelength resolution and response speed can achieve 0.34 pm and 500 kHz, respectively.
Micro parts with high aspect ratios have been widely used in different fields including aerospace and defense industries, while the dimensional measurement of these micro parts becomes a challenge in the field of precision measurement and instrument. To deal with this contradiction, several probes for the micro parts precision measurement have been proposed by researchers in Center of Ultra-precision Optoelectronic Instrument (UOI), Harbin Institute of Technology (HIT). In this paper, optical fiber probes with structures of spherical coupling(SC) with double optical fibers, micro focal-length collimation (MFL-collimation) and fiber Bragg grating (FBG) are described in detail. After introducing the sensing principles, both advantages and disadvantages of these probes are analyzed respectively. In order to improve the performances of these probes, several approaches are proposed. A two-dimensional orthogonal path arrangement is propounded to enhance the dimensional measurement ability of MFL-collimation probes, while a high resolution and response speed interrogation method based on differential method is used to improve the accuracy and dynamic characteristics of the FBG probes. The experiments for these special structural fiber probes are given with a focus on the characteristics of these probes, and engineering applications will also be presented to prove the availability of them. In order to improve the accuracy and the instantaneity of the engineering applications, several techniques are used in probe integration. The effectiveness of these fiber probes were therefore verified through both the analysis and experiments.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.