A tunable polarization mode dispersion (PMD) compensator based on strain-ckirped fiber Bragg gratings (FBGs) is proposed. It natures in flexible designing, large tuning range, without using linear or nonlinear chirped...A tunable polarization mode dispersion (PMD) compensator based on strain-ckirped fiber Bragg gratings (FBGs) is proposed. It natures in flexible designing, large tuning range, without using linear or nonlinear chirped phase mask, fast tuning response time, continuously adjustable, all-fiber based, compact, and cheap.展开更多
Some practical research topics on tunable fiber gratings in author's group are presented, including tuning speed, tuning range, tuning characteristics of gratings in HB fiber, and the tunability of the line-width....Some practical research topics on tunable fiber gratings in author's group are presented, including tuning speed, tuning range, tuning characteristics of gratings in HB fiber, and the tunability of the line-width. The applications of fiber gratings in communication and sensing are also discussed.展开更多
A switchable dual-wavelength erbium-doped fiber laser(EDFL) with tunable wavelength is demonstrated. The ring cavity consists of two branches with a fiber Bragg grating(FBG) and a spherical-shape structure as fiber fi...A switchable dual-wavelength erbium-doped fiber laser(EDFL) with tunable wavelength is demonstrated. The ring cavity consists of two branches with a fiber Bragg grating(FBG) and a spherical-shape structure as fiber filters, respectively. By adjusting the variable optical attenuator(VOA), the laser can be switched between the single-wavelength mode and the dual-wavelength mode. The spherical-shape structure has good sensitivity to the temperature. When the temperature changes from 30 °C to 190 °C, the central wavelength of the EDFL generated by the branch of spherical-shape structure varies from 1 551.6 nm to 1 561.8 nm, which means that the wavelength interval is tunable.展开更多
A new wavelength division multiplexing method for fiber Bragg grating（FBG） sensors based on spectrum profile identification is proposed. In this method, FBGs and tilted FBG（TFBG） sensors are cascaded in a single f...A new wavelength division multiplexing method for fiber Bragg grating（FBG） sensors based on spectrum profile identification is proposed. In this method, FBGs and tilted FBG（TFBG） sensors are cascaded in a single fiber in one sensing channel. The different spectrum profiles enable the cross-correlation method to demodulate the wavelength. Therefore, the different types of sensors can occupy the same central wavelength band. Using this method, the multiplexing capacity is optimized. Experiment results demonstrate the feasibility of this method and it is useful for applications where large numbers of FBGs are needed.展开更多
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 F...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.展开更多
This Letter presents a method of an optical sensor for measuring wavelength shifts. The system consists of a diffraction grating and a total internal reflection heterodyne interferometer. As a heterodyne light beam st...This Letter presents a method of an optical sensor for measuring wavelength shifts. The system consists of a diffraction grating and a total internal reflection heterodyne interferometer. As a heterodyne light beam strikes a grating, the first-order diffraction beam is generated. The light penetrates into a total internal reflection prism at an angle larger than the critical angle. A wavelength variation will affect the diffractive angle of the first-order beam, thus inducing a phase difference variation of the light beam emerging from the total internal reflections inside the trapezoid prism. Both the experimental and theoretical results reveal that, for the first-order diffractive beam, the sensitivity and resolution levels are superior to 5°/nm and 0.006 nm, respectively, in the range of wavelength from 632 to 634 nm, and are superior to 3.1°/nm and 0.0095 nm in the range from 632 to 637 nm. For the theoretical simulation of the fourth-order diffractive beam, they are superior to 6.4 deg ∕nm and 0.0047 nm in the range from 632 to 637 nm.展开更多
基金This work was supported by the National 973 Basic Research and Development Program of China (No. 2003CB314901), the National Natural Science Foundation of China (No. 60377026), the National "863" High Technology Project of China (No. 2003AA311070),
文摘A tunable polarization mode dispersion (PMD) compensator based on strain-ckirped fiber Bragg gratings (FBGs) is proposed. It natures in flexible designing, large tuning range, without using linear or nonlinear chirped phase mask, fast tuning response time, continuously adjustable, all-fiber based, compact, and cheap.
文摘Some practical research topics on tunable fiber gratings in author's group are presented, including tuning speed, tuning range, tuning characteristics of gratings in HB fiber, and the tunability of the line-width. The applications of fiber gratings in communication and sensing are also discussed.
基金supported by the National High Technology Research and Development Program of China(No.2013AA014201)the Tianjin Youth Science Foundation(No.13JCQNJC01800)
文摘A switchable dual-wavelength erbium-doped fiber laser(EDFL) with tunable wavelength is demonstrated. The ring cavity consists of two branches with a fiber Bragg grating(FBG) and a spherical-shape structure as fiber filters, respectively. By adjusting the variable optical attenuator(VOA), the laser can be switched between the single-wavelength mode and the dual-wavelength mode. The spherical-shape structure has good sensitivity to the temperature. When the temperature changes from 30 °C to 190 °C, the central wavelength of the EDFL generated by the branch of spherical-shape structure varies from 1 551.6 nm to 1 561.8 nm, which means that the wavelength interval is tunable.
基金supported by the National Instrumentation Program of China(No.2013YQ030915)the National Natural Science Foundation of China(Nos.61227011,61378043,61505139,61475114,and 11004150)+3 种基金the Tianjin Natural Science Foundation(No.13JCYBJC16200)the Shenzhen Science and Technology Research Project(No.JCYJ20120831153904083)the National Basic Research Program of China(No.2010CB327802)the Soft Science Research and Development Project of the Ministry of Housing and Urban-Rural Development of China(No.2016-K4-087)
文摘A new wavelength division multiplexing method for fiber Bragg grating（FBG） sensors based on spectrum profile identification is proposed. In this method, FBGs and tilted FBG（TFBG） sensors are cascaded in a single fiber in one sensing channel. The different spectrum profiles enable the cross-correlation method to demodulate the wavelength. Therefore, the different types of sensors can occupy the same central wavelength band. Using this method, the multiplexing capacity is optimized. Experiment results demonstrate the feasibility of this method and it is useful for applications where large numbers of FBGs are needed.
基金supported by the National Natural Science Foundation of China(No.60777020)the Hubei Provincial Natural Science Foundation of China(No.2008CDB317)the Innovation Project of Hubei Provincial Department of Education of China(No.2012344/104892013043)
文摘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.
文摘This Letter presents a method of an optical sensor for measuring wavelength shifts. The system consists of a diffraction grating and a total internal reflection heterodyne interferometer. As a heterodyne light beam strikes a grating, the first-order diffraction beam is generated. The light penetrates into a total internal reflection prism at an angle larger than the critical angle. A wavelength variation will affect the diffractive angle of the first-order beam, thus inducing a phase difference variation of the light beam emerging from the total internal reflections inside the trapezoid prism. Both the experimental and theoretical results reveal that, for the first-order diffractive beam, the sensitivity and resolution levels are superior to 5°/nm and 0.006 nm, respectively, in the range of wavelength from 632 to 634 nm, and are superior to 3.1°/nm and 0.0095 nm in the range from 632 to 637 nm. For the theoretical simulation of the fourth-order diffractive beam, they are superior to 6.4 deg ∕nm and 0.0047 nm in the range from 632 to 637 nm.
