Fiber Bragg Grating Fabry-Perot Research Articles

PCF-Cavity FBG Fabry-Perot Resonator for Simultaneous Measurement of Pressure and Temperature

In this paper, we propose a Photonic Crystal Fiber (PCF)-cavity fiber Bragg grating (FBG) Fabry-Perot resonator for simultaneous sensing of temperature and pressure. The proposed device is constructed by splicing a 1.5-mm long PCF segment between two identical saturated FBGs written in SMF-28 forming an FBG-PCF-FBG configuration. As a result, a resonance dip is created within the Bragg reflection curve. Taking advantage of the difference in pressure sensitivities between the two types of fiber, the discriminative measurement of pressure and temperature can be achieved from the shifts of the resonance wavelength and band-edge wavelength. In addition, the same temperature sensitivity of PCF and SMF-28 provides the convenience of eliminating the temperature variable and achieving temperature insensitive pressure measurement.

Compact slow-light single-frequency fiber laser at 1550 nm

A compact several-hundred-Hz-linewidth single-frequency fiber laser based on the slow-light effect induced by a fiber-Bragg-grating Fabry–Perot (FBG-FP) filter is demonstrated. An FBG-FP filter is utilized for optical time delay, extending the efficient cavity length of the resonator. As a result, a slow-light short-linear-cavity fiber laser at 1550 nm with a linewidth less than 780 Hz is obtained. The relaxation oscillation frequency is around 234 kHz owing to the slow-light effect, and the relative intensity noise is less than −150 dB/Hz at 25 kHz.

Design of fiber magnetic field sensor based on fiber Bragg grating Fabry-Perot cavity ring-down spectroscopy

A novel fiber magnetic sensor based on the fiber Bragg grating Fabry-Perot (FBG-FP) cavity ring-down technique with pulse laser injection is proposed and demonstrated theoretically. A general expression of the intensity of the output electric field is derived, and the effect of the external magnetic field on the ring-down time is discussed. The results show that the output light intensity and the ring-down time of the FBG-FP cavity are in the inverse proportion to the magnitude of the external magnetic field. Our results demonstrate the new concept of the fiber magnetic sensor with the FBG-FP cavity ring-down spectroscopy and the technical feasibility.

Dual-wavelength erbium-doped fiber laser with asymmetric fiber Bragg grating Fabry-Perot cavity

A novel dual-wavelength fiber laser with asymmetric fiber Bragg grating (FBG) Fabry-Perot (FP) cavity is proposed and experimentally demonstrated. A couple of uniform FBGs are used as the cavity mirrors, and the third FBG is used as intracavity wavelength selector by changing its operation temperature. Experimental results show that by adjusting the operation temperature of the intracavity wavelength selector, a tunable dual-wavelength laser emission can be achieved. The results demonstrate the new concept of dual-wavelength lasing with asymmetric FBG FP resonator and its technical feasibility.

Measurement of Er3+-doped concentration in optical fiber by using fiber Bragg grating Fabry-rerot cavity ring-down spectrum

We propose and experimentally demonstrate a novel approach to measure the Er3+ concentration in Er3+-doped silica fiber by fiber Bragg grating Fabry-Perot (FBG-FP) cavity ring-down spectrum. The relationship between the cavity ring-down time and the Er3+-doped concentration is derived. The results demonstrate that the cavity ring-down time is a function of the temperature of FBG, and an Er3+-doped concentration of 0.3 × 1025 m-3 at the FBG operation temperature of 25℃ is obtained, which is consistent with the commercial Er3+-doped silica fiber parameter. The results obtained have theoretical guidance and develop a new method to measure the ion doped concentration in solid matter.

Simultaneous measurement of absolute strain and differential strain based on fiber Bragg grating Fabry–Perot sensor

We present a fiber Bragg grating Fabry–Perot (FBG-FP) sensor using the fast Fourier transform (FFT) demodulation for measuring the absolute strain and differential strain simultaneously. The amplitude and phase characteristics of Fourier transform spectrum have been studied. The relation between the amplitude of Fourier spectrum and the differential strain has been presented. We fabricate the fiber grating FP cavity sensor, and carry out the experiment on the measurement of absolute strain and differential strain. Experimental results verify the demodulation method, and show that this sensor has a good accuracy in the scope of measurement. The demodulating method can expand the number of multiplexed sensors combining with wavelength division multiplexing and time division multiplexing.

基于光纤光栅法布里珀罗干涉仪的液体介质声波检测技术研究

基于光纤光栅法布里珀罗干涉仪的液体介质声波检测技术研究

光纤布拉格光栅法布里珀罗腔时延和色散特性的研究

光纤布拉格光栅法布里珀罗腔时延和色散特性的研究

Application of Fiber Bragg Grating Level Sensor and Fabry-Pérot Pressure Sensor to Simultaneous Measurement of Liquid Level and Specific Gravity

This study is proposed for obtaining simultaneous measurements of the level and specific gravity of a liquid using a dual-optical-fiber-sensor system comprising a fiber Bragg grating (FBG) level sensor and a Fabry-Perot (FP) pressure sensor. In the FBG level sensor, the liquid level is derived from the FBG wavelength shift induced when the buoyancy is applied on a cantilever beam. Meanwhile, in the FP sensor, the pressure is calculated from the change in cavity length which takes place when the sensor is immersed. The experimental results show that the FBG level and FP pressure sensors have sensitivities of 0.01491 nm/cm and 0.1569 μm/kPa, respectively. Analytical formulae are derived for the level and specific gravity of the liquid in terms of the Bragg wavelength shift, the change in cavity length, and the vertical separation distance between the two sensors. The average measurement errors of the liquid level and specific gravity are found to be 0.0323 and 0.0528 m, respectively.

基于法布里珀罗结构的光纤光栅功能型器件

基于法布里珀罗结构的光纤光栅功能型器件

基于光纤光栅法布里珀罗腔锁频原理的高灵敏度光纤振动传感器

基于光纤光栅法布里珀罗腔锁频原理的高灵敏度光纤振动传感器

基于光纤光栅法布里珀罗腔锁频原理的高灵敏度光纤振动传感器

基于光纤光栅法布里珀罗腔锁频原理的高灵敏度光纤振动传感器

基于光纤光栅法布里珀罗腔锁频原理的高灵敏度光纤振动传感器

基于光纤光栅法布里珀罗腔锁频原理的高灵敏度光纤振动传感器

DBR光纤激光器有效腔长测量新方法

A novel method to measure the effective cavity length of distributed Bragg reflector (DBR) fiber laser with fiber Bragg grating (FBG) Fabry-Perot cavity as the resonator is proposed. The effective cavity length of DBR fiber laser is accurately measured by measuring the frequency spacing of two adjacent longitudinal modes in the cavity without the precise physical length of FBGs. The measuring accuracy as high as 10-5 mm can be obtained by setting the resolution bandwidth of the spectrum analyzer.

Study of the characteristics of concentration sensing based on FBG Fabry-Perot cavity

Fiber Bragg grating Fabry-Perot (FBG F-P) cavity is used as the sensing model to measure the refractive index of the liquid solution. The cladding of the fiber, which is used as the F-P cavity, is etched by HF solution to enhance the sensitivity to the external refractive index. The experimental results show that with the concentration change of the external solution, the effective refractive index of etched fiber will change, thus the spectra of FBG F-P cavity will appear a spilt point. The relationship between the wavelength at spilt point and the effective refractive index of etched fiber is approximately linear, and also periodical. The sensing model is theoretically analyzed based on transfer matrix method, and the corresponding mathematic model is established.

Phase-modified coupled mode theory for calculation of fiber Bragg grating Fabry-Perot cavity transmission spectrum

Based on the influence of reflection phase of fibre Bragg grating on the transmission spectrum of fibre Bragg grating(FBG) Fabry-Perot cavity, the reason for the error of traditional coupled mode theory when calculating the reflection phase of uniform FBG is analyzed. A parameter of initial phase of effective index distribution is introduced to describe the slight offset of the index distribution of FBG in the longitudinal direction, and the real reflection and transmission coefficients are substituted for the simplified coefficients to modify the traditional coupled mode theory by introducing a phase factor, which is related with the initial phase of effective index distribution and independent of wavelength. The phase of transfer matrix method for nonuniform FBG is further modified. The modified fast calculation results are used to calculate the transmission spectrum of FBG F-P cavity and show the influence of initial phase of effective index distribution on the wavelength offset of FBG Fabry-Perot cavity transmission peaks. The results agree with those of Rouard method and experimental values.