A stable and broadband microwave photonic phase shifter based on the combined use of a linear chirped fiber Bragg grating and optical single-sideband （OSSB） modulation is proposed and experimentally demonstrated. Th...A stable and broadband microwave photonic phase shifter based on the combined use of a linear chirped fiber Bragg grating and optical single-sideband （OSSB） modulation is proposed and experimentally demonstrated. The quality of the radio frequency （RF） signal is improved by the spectral separation delay processing. The theoretical fundamentals of the scheme are explained and the phase shift can be controlled linearly by the wave- length of the light source. In the experiment, a full 360° phase shift with a 10 GHz bandwidth can be achieved and tuned dynamically, continuously, and stably.展开更多
We presented an interferometric phase shift fiber Bragg grating （FBG） sensor, which inherited the advantages of FBG sensors, and, at the same time, the greatly reduced full-width-at-half-maximum bandwidth brought lo...We presented an interferometric phase shift fiber Bragg grating （FBG） sensor, which inherited the advantages of FBG sensors, and, at the same time, the greatly reduced full-width-at-half-maximum bandwidth brought longer coherent length, higher sensitivity, and lower phase noise. Experiments show that at least a 7 dB reduction of phase noise can be achieved compared to FBG sensors interrogated by interferometer with the same optical path difference.展开更多
A phase-shifted fiber Bragg grating(PS-FBG) based on a microchannel was proposed and realized by combining the pointby-point scanning method with chemical etching. The PS-FBG is composed of a fiber Bragg grating(FBG) ...A phase-shifted fiber Bragg grating(PS-FBG) based on a microchannel was proposed and realized by combining the pointby-point scanning method with chemical etching. The PS-FBG is composed of a fiber Bragg grating(FBG) and a microchannel through the fiber core. The microchannel can introduce phase shift into the FBG. What is more important is that it exposes the fiber core to the external environment. The phase shift peak is sensitive to the liquid refractive index, and it shows a linear refractive index response wavelength and intensity sensitivity of 2.526 nm/RIU and-111 d B/RIU, respectively.Therefore, such gratings can be used as sensors or tunable filters.展开更多
Based on the transfer matrix method,a detailed theoretical and numerical study on double-phase-shifted fiber Bragg grating(FBG)is investigated.Temporal responses of the double-phase-shifted FBG to optical pulse are an...Based on the transfer matrix method,a detailed theoretical and numerical study on double-phase-shifted fiber Bragg grating(FBG)is investigated.Temporal responses of the double-phase-shifted FBG to optical pulse are analyzed and the influence of the two phase-shifts’position on the reflected output pulse is evaluated.Results demonstrate that very different temporal pulse waveforms can be achieved by adjusting the length ratio(α=L2/L1).Specifically,a transform-limited Gaussian input optical pulse can be shaped into flat-top square pulse(α=1.81)or two identical optical pulse sequences(α=1.93).展开更多
A n-phase-shifted fiber Bragg grating theoretical model is established, and the effects of an asymmetric and symmetrical perturbation field on a phase-shifted fiber Bragg grating are investigated in this paper. The tr...A n-phase-shifted fiber Bragg grating theoretical model is established, and the effects of an asymmetric and symmetrical perturbation field on a phase-shifted fiber Bragg grating are investigated in this paper. The trends of wavelength shifting caused by effective refraction index of phase shift grating in symmetric and asymmetric acoustic field are investigated in detail. Then, the fiber laser acoustic sensors packaged in asymmetric and symmetrical structures are designed and tested, respectively. The results show that the acoustic response of the wavelength of the distributed feedback （DFB） fiber laser （FL） in an asymmetric packaging structure is much more sensitive than in that in the symmetrical structure. The sensor packaged in the asymmetrical structure has a better low frequency （0Hz-500Hz） performance and a higher sensitivity than that in the symmetrical structure, and the sensitivity is improved about 15dB in average and 32.7dB in maximum. It provides a new method to improve the sensitivity of the fiber acoustic sensor.展开更多
A new method of fabricating multiple-phase-shifts fiber Bragg grating by CGHsis proposed . The authors present an example of such CGH by which a section multiple-phase-shiftefiber Bragg grating with twoπ/2 phase shif...A new method of fabricating multiple-phase-shifts fiber Bragg grating by CGHsis proposed . The authors present an example of such CGH by which a section multiple-phase-shiftefiber Bragg grating with twoπ/2 phase shifts and grating length L = 21.2 μm was produced. Theauthors describe the production process and finally give an example of a reconstructed fiber gratingwith two phase-shifts.展开更多
This paper proposed and experimentally demonstrated an all-fiber tunable and programmable bandpass filter using a linearly chirped fiber Bragg grating （CFBG）. The center wavelength and spacing of the transmission pe...This paper proposed and experimentally demonstrated an all-fiber tunable and programmable bandpass filter using a linearly chirped fiber Bragg grating （CFBG）. The center wavelength and spacing of the transmission peaks could be independently tuned via computer. The tunable range is about 18 rim. With this filter we demonstrated a tunable fiber ring laser which has an output power of about -7 dBm, full-width at half- maximum linewidth of-0.017 nm which is limited by the resolution of the optical spectrum analyzer （OSA）. Furthermore, a spacing tunable dual-wavelength fiber laser was achieved with the same setup. This all-fiber laser features advantages like simple structure, low cost, flexible and digital tuning capability.展开更多
基金supported by the National "973" Program of China(No.2012CB315604)the Natural Science Foundation of China(Nos.61575028 and 61331008)+2 种基金the Program for New Century Excellent Talents in University(No.NCET-12-0793)the Beijing Nova Program (No.2011065)the Open Fund of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications)
文摘A stable and broadband microwave photonic phase shifter based on the combined use of a linear chirped fiber Bragg grating and optical single-sideband （OSSB） modulation is proposed and experimentally demonstrated. The quality of the radio frequency （RF） signal is improved by the spectral separation delay processing. The theoretical fundamentals of the scheme are explained and the phase shift can be controlled linearly by the wave- length of the light source. In the experiment, a full 360° phase shift with a 10 GHz bandwidth can be achieved and tuned dynamically, continuously, and stably.
基金supported by the National Natural Science Foundation of China(No.11574397)the Research Plan of National University of Defense Technology(No.ZK16-03-56)
文摘We presented an interferometric phase shift fiber Bragg grating （FBG） sensor, which inherited the advantages of FBG sensors, and, at the same time, the greatly reduced full-width-at-half-maximum bandwidth brought longer coherent length, higher sensitivity, and lower phase noise. Experiments show that at least a 7 dB reduction of phase noise can be achieved compared to FBG sensors interrogated by interferometer with the same optical path difference.
基金supported by the National Natural Science Foundation of China (Nos. 51875584, 51935013, and 51875585)the National Key R&D Program of China (Nos. 2018YFB1107803 and 2017YFB1104800)。
文摘A phase-shifted fiber Bragg grating(PS-FBG) based on a microchannel was proposed and realized by combining the pointby-point scanning method with chemical etching. The PS-FBG is composed of a fiber Bragg grating(FBG) and a microchannel through the fiber core. The microchannel can introduce phase shift into the FBG. What is more important is that it exposes the fiber core to the external environment. The phase shift peak is sensitive to the liquid refractive index, and it shows a linear refractive index response wavelength and intensity sensitivity of 2.526 nm/RIU and-111 d B/RIU, respectively.Therefore, such gratings can be used as sensors or tunable filters.
基金supported by the Foundation of Beijing Municipal Committee of CPC Organization Department(No.2012D005002000001)the Talents of North China University of Technology(No.CCXZ201307)the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions(No.CIT&TCD201304001)
文摘Based on the transfer matrix method,a detailed theoretical and numerical study on double-phase-shifted fiber Bragg grating(FBG)is investigated.Temporal responses of the double-phase-shifted FBG to optical pulse are analyzed and the influence of the two phase-shifts’position on the reflected output pulse is evaluated.Results demonstrate that very different temporal pulse waveforms can be achieved by adjusting the length ratio(α=L2/L1).Specifically,a transform-limited Gaussian input optical pulse can be shaped into flat-top square pulse(α=1.81)or two identical optical pulse sequences(α=1.93).
基金This work was supported by the Natural Science Foundation of Shandong Province of China （Grant No. ZR2016FB03）, the National Natural Science Foundation of China （Grant No. 61705121＆ No.21603122）, and the Ph.D. Foundation of Shandong Jianzhu University （Grant No. XNBS1535）.
文摘A n-phase-shifted fiber Bragg grating theoretical model is established, and the effects of an asymmetric and symmetrical perturbation field on a phase-shifted fiber Bragg grating are investigated in this paper. The trends of wavelength shifting caused by effective refraction index of phase shift grating in symmetric and asymmetric acoustic field are investigated in detail. Then, the fiber laser acoustic sensors packaged in asymmetric and symmetrical structures are designed and tested, respectively. The results show that the acoustic response of the wavelength of the distributed feedback （DFB） fiber laser （FL） in an asymmetric packaging structure is much more sensitive than in that in the symmetrical structure. The sensor packaged in the asymmetrical structure has a better low frequency （0Hz-500Hz） performance and a higher sensitivity than that in the symmetrical structure, and the sensitivity is improved about 15dB in average and 32.7dB in maximum. It provides a new method to improve the sensitivity of the fiber acoustic sensor.
文摘A new method of fabricating multiple-phase-shifts fiber Bragg grating by CGHsis proposed . The authors present an example of such CGH by which a section multiple-phase-shiftefiber Bragg grating with twoπ/2 phase shifts and grating length L = 21.2 μm was produced. Theauthors describe the production process and finally give an example of a reconstructed fiber gratingwith two phase-shifts.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Grant No. 61107087） and the National High Technology Research and Development Program of China （863 Program） （No. SS2012AA010407）.
文摘This paper proposed and experimentally demonstrated an all-fiber tunable and programmable bandpass filter using a linearly chirped fiber Bragg grating （CFBG）. The center wavelength and spacing of the transmission peaks could be independently tuned via computer. The tunable range is about 18 rim. With this filter we demonstrated a tunable fiber ring laser which has an output power of about -7 dBm, full-width at half- maximum linewidth of-0.017 nm which is limited by the resolution of the optical spectrum analyzer （OSA）. Furthermore, a spacing tunable dual-wavelength fiber laser was achieved with the same setup. This all-fiber laser features advantages like simple structure, low cost, flexible and digital tuning capability.
