In this paper, the fiber Bragg gratings wavelength demodulation system based on tilted fiber grating is designed. The temperature sensing characteristic is researched. The demodulation system is formed by a tilted fiber grating, four sensing FBGs, One broadband light source and four photodetectors. The tilted fiber grating is as edge filter. The central wavelengths of the four FBGs are 1560.0nm, 1561.5nm, 1563.0nm and 1564.5nm respectively. When the temperature increases gradually from 0 °C to 105 °C, the simulation results show that the demodulation range of four FBGs is from 1560.0nm-1566nm, the sensitivity of FBG1, FBG2, FBG3 and FBG4 are 0.458 mW/°C, 0.564mw/°C, 0.651mw/°C and 0.559mw/°C, respectively. This system provides a new demodulation scheme for array sensing.
In this paper, a new structure of optical filter based on micro-ring resonator (MRR) and Bragg grating is proposed. The micro-ring resonator consists of two linear waveguides, one ring waveguide and two Bragg gratings. The filter has four ports. When optical signal input from one of the four ports, the output optical signals output from other three ports. The spectra of output ports of the optical filter are analyzed by using transmission matrix method. The result shows that the output channels of this optical filter are twice as large as that of the micro-ring resonator without Bragg gratings.
In this paper, the cascade tilted fiber Bragg grating (CTFBG) is theoretically deduced through the transfer matrix method. The spectral characteristics of CTFBG with different structural parameters are simulated and analyzed in detail. The structural parameters include the tilted angle, the cascaded number and the grating period of CTFBG. The temperature and strain sensing characteristics of CTFBG are studied. When the temperature increases gradually from 10°C to 100°C, the wavelength drift of the CTFBG is 1.32 nm, and the sensitivity of the temperature is 0.0147nm/°C. Compared with tilted fiber Bragg grating (TFBG), CTFBG not only has more abundant spectral characteristics, but also has higher sensitivity than TFBG temperature sensor, which improves the sensitivity of temperature sensor. In addition, the sensitivity of the CTFBG strain sensor is also simulated. When the strain increases from 0 to 2000με , the wavelength shift of CTFBG is 2.168 nm, and the sensitivity of the strain is 0.001084 nm / με , which is slightly higher than that of TFBG strain sensor. The research results provide a theoretical basis for the application in the field of optical sensing. Therefore, it has very important research significance.
In order to study the properties of phase-shifted fiber Bragg grating, The reflection spectrum characteristic of phase-shifted fiber grating with different fiber grating length, different refractive index modulation depth and different shift angle are analyzed using transmission matrix method. A new scheme of optical add-drop multiplexer based on phase-shifted fiber Bragg grating and Mach-Zehnder interferometer is proposed and simulated. The reflection spectrum of phase-shifted fiber grating is optimized using Gauss apodization function. Two channel signals can be dropped simultaneously. This study may provide theory instruction for the application of the OADM.
A fiber Bragg grating (FBG) sensor for simultaneous measurement of temperature and force is proposed and demonstrated. Where a part of uniform FBG (about one half length of an FBG) is attached on the polymer open loop, the FBG is divided into two parts which has an equal length. So the two parts can be regarded as two FBGs. Because of the difference of the Young’s modulus and the thermal expansion coefficients for two parts of the FBG, the two Bragg reflection wavelengths are shift when the temperature and force are applied on the sensor. Simultaneous measurement of temperature and force is demonstrated experimentally. The experimental results show that the linear response to temperature and force are achieved. The value of applied temperature and force can be obtained from the two Bragg wavelength shift via the coefficient matrix. This study provides a simple and economical method to measure temperature and force simultaneously.
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.