Author Affiliations
Abstract
1 School of Physics, Northwest University, Xi’an 710127, China
2 Department of Electrical and Electronic Engineering, Joint Appointment with School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
In this Letter, we developed a robust method for integrating nanodiamonds (NDs) to optical fiber. The NDs, containing nitrogen-vacancy (NV) centers, were uniformly mixed with UV adhesive before coating the end surface of a multimode fiber as a hemispherical film. The excitation and collection efficiency of NV fluorescence can be enhanced by increasing the thickness of UV adhesive film and additional aluminum film deposition. The fiber-based quantum sensor was also experimentally demonstrated for all-optical thermometry application. The variation of the refractive index of UV adhesive under different temperatures will also affect the NV collection efficiency by changing the light confinement. The demonstrated facile integration approach paves the way for developing fiber-based quantum thermometry and magnetometry.
fiber optics sensors fiber optics quantum optics Chinese Optics Letters
2021, 19(12): 120601
Author Affiliations
Abstract
1 School of Physics, Northwest University, Xi’an 710069, China
2 Xi’an Research Institute of Hi-Tech, Xi’an 710065, China
An evanescent field optical fiber sensor based on a short section of polarization maintaining fiber spliced with a tapered single mode fiber is proposed and experimentally investigated. We mainly focus on the refractive index (RI) and temperature sensing characteristics of this compact device. The transmission spectrum of the resonance wavelength, induced by the interference between the excited low order cladding modes and core modes, shows the quadratic function relationships with RI and linear relationships with temperature. Thus, the proposal of this simple-to-fabricate, compact, and low cost sensor shows its possible potential in the sensitive detection field.
060.0060 Fiber optics and optical communications 060.2310 Fiber optics 060.2370 Fiber optics sensors Chinese Optics Letters
2016, 14(5): 050604
Author Affiliations
Abstract
1 Xi’an Research Institute of High-Technology, Xi’an 710025, China
2 Department of Physics, Northwest University, Xi’an 710069, China
3 e-mail: zhongb_qin@163.com
A hybrid fiber interferometer sensing configuration for displacement and temperature measurements is proposed and experimentally demonstrated that is constructed by splicing a short section of polarization maintaining optical fiber to an end-cleaved single mode optical fiber with a tapering structure. The reflected spectrum changes with the variation of displacement and temperature. The sensing configuration uses the method of wavelength and intensity modulations for displacement and temperature measurements, respectively, to which the sensitivities are 0.01392 nm/μm, 0.0214 dBm/μm, 0.09136 nm/°C, and 0.15795 dBm/°C. Experimental results show that displacement and temperature can be measured simultaneously by demodulating the reflected spectrum.
060.0060 Fiber optics and optical communications 060.2310 Fiber optics 060.2370 Fiber optics sensors Chinese Optics Letters
2015, 13(5): 050603
1 西北大学物理学院, 陕西 西安 710069
2 陕西科技大学理学院, 陕西 西安 710021
3 中国科学院西安光学精密机械研究所, 陕西 西安 710119
浑浊介质引起的多光散射会扭曲光波传播，使图像变得模糊。浑浊透镜成像（TLI）则可以重建这种被扭曲的图像。在该方法中，需要提取输光场的复电场（复振幅）信息，以计算浑浊介质的传输矩阵。但是CCD记录的是图像的强度信息，丢失了扭曲光场的相位信息。由于物光经过浑浊介质后变成了强度剧烈变化的散斑图像，直接进行相位解调会产生较大误差。为了消除散斑强度变化的影响，分别记录扭曲光场图像、参考光图像、干涉条纹图像和背景光图像。根据对应关系换算出干涉余弦因子，对余弦因子应用希尔伯特变换进行相位解调就可以比较准确地计算出散斑的相位。通过上述方法成功地计算出扭曲图像的复电场及浑浊介质的传输矩阵。由于对振幅的测量采用直接方法，因而对于散斑干涉条纹来说，该方法的计算结果更加准确。
成像系统 相位解调 希尔伯特变换 浑浊介质成像 光学学报
2015, 35(s1): s111005
提出一种具有温度自校准功能的光纤折射率(RI)传感器, 传感头结构由2段很短的多模光纤(MMF)之间夹熔一段对折射率不敏感的光纤布拉格光栅(FBG)构成, 传感头总长度为14 mm, FBG可以为折射率测量提供良好的温度校准功能。实验结果证明, 该传感器的折射率灵敏度为126 nm。其干涉光谱共振波长的温度灵敏度为35.09 pm/℃, 用于温度校准的FBG的温度灵敏度为11.14 pm/℃。相比于普通的折射率传感器, 这种具有温度自校准功能的折射率传感器具有良好的实用前景。
光纤传感器 折射率 多模光纤 布拉格光栅 optical fiber sensor refractive index multimode fiber fiber Bragg grating
Author Affiliations
Abstract
A sensing structure consisting of an abrupt taper spliced uniformly in to a fiber Bragg grating (FBG) is proposed and experimentally demonstrates refractive index (RI) and temperature measurements. Cladding modes are generated in the fiber through the abrupt taper containing the FBG. Most modes are reflected by the FBG at shorter wavelengths and reenter the launch fiber after passing through the abrupt taper. Spectral integrals are used to measure the power generated by the cladding and core modes. A sensitivity of -83.97 nW/RIU for ambient RI and a temperature sensitivity of 10 pm/C are obtained. No crosssensitivity problems exist between ambient RI and temperature measurement.
060.2370 Fiber optics sensors 060.3735 Fiber Bragg gratings 280.6780 Temperature Chinese Optics Letters
2013, 11(12): 120604
研究了不同尺寸SiO2胶体微球形成纳米结构薄膜的光学传输特性和光子带隙。通过在玻璃基底上自组装透光的SiO2胶体微球形成胶体晶体薄膜, 依据布拉格定律，分析微球尺寸对胶体晶体光子带隙的影响。为实现可见光波段的全方位减反射，提出通过改变胶体粒径将胶体晶体带隙位置移动至紫外波段，理论计算得出当粒径为112 nm，占空比为0.45时能实现可见光波段0.5%的平均反射率。实验结果表明，玻璃基底在400~800 nm间的平均反射率从4.3%降低至0.7%，最小反射率达0.3%。通过控制微球粒径移动光子带隙位置，优化晶体结构参数实现了可见光波段的减反射，有效提高了光学组件对可见光的利用率。
薄膜 减反膜 SiO2胶体晶体 自组装 亚波长纳米结构 光学学报
2012, 32(12): 1216001
Author Affiliations
Abstract
A micro Fabry-Perot interferometer (M-FPI) is constructed by splicing a short section of polarization-maintaining photonic crystal fiber (PM-PCF) to an end-cleaved single-mode fiber with controllable offset. Due to the high effective optical path difference induced by the solid core of the PCF, the M-FPI has an ultrasmall cavity of approximately 110 \mu m. The temperature sensitivity within a range from 33 oC to approximately 600 oC is measured to be 13.8 pm/oC, which shows good agreement with the theoretical result. This proposed sensor has the advantages of ultracompact size and high stability. Therefore, it is suitable for various space-limited sensing applications in harsh environments.
060.0060 Fiber optics and optical communications 060.2310 Fiber optics 060.2370 Fiber optics sensors 060.2430 Fibers, single-mode Chinese Optics Letters
2012, 10(7): 070607
Author Affiliations
Abstract
A simple fiber tip sensor for refractive index (RI) measurement based on Fabry–Perot (FP) interference modulated by Fresnel reflection is proposed and demonstrated. The sensor head consists of an etching-induced micro air gap near the tip of a single-mode fiber. The microgap and the fiber tip function as two reflectors to form a FP cavity. The external RI can be unambiguously measured by monitoring the fringe contrast of the interference pattern from the reflection spectrum. The experimental results show that the proposed sensor achieves temperature-independent RI measurement with good linear response. The proposed sensor achieves a high RI resolution of up to 3.4 \times 10 5 and has advantages of low cost and easy fabrication.
060.2370 Fiber optics sensors 120.2230 Fabry-Perot Chinese Optics Letters
2012, 10(5): 050603
Author Affiliations
Abstract
A novel all-fiber temperature-calibrated refractometer based on a compact fiber Bragg grating (FBG) single–multi–single (SMS) structure is proposed and experimentally demonstrated. The sensor head is composed of a FBG combined with a SMS structure, in which the middle multimode fiber (MMF) section is etched by a time-controlled hydrofluoric. The transmission dip of SMS is extremely sensitive to ambient refractive index (RI) variation, whereas the upstream FBG provides the necessary temperature information for RI calibration. All aforementioned functions are performed via a compact FBG-SMS structure not longer than 25 mm. The proposed sensing device provides a linear RI sensitivity over water or waterbased solutions (RI values near 1.33 at optical wavelengths for most biological and many environmental applications), and has temperature-calibration capability. Hence, the said refractometer is a good candidate for sensing in chemical and biological applications.
060.2370 Fiber optics sensors 060.3735 Fiber Bragg gratings Chinese Optics Letters
2012, 10(3): 030604
