Metasurfaces in the long wave infrared(LWIR)spectrum hold great potential for applications in ther-mal imaging,atmospheric remote sensing,and target identification,among others.In this study,we designed and experiment...Metasurfaces in the long wave infrared(LWIR)spectrum hold great potential for applications in ther-mal imaging,atmospheric remote sensing,and target identification,among others.In this study,we designed and experimentally demonstrated a 4 mm size,all-silicon metasurface metalens with large depth of focus opera-tional across a broadband range from 9µm to 11.5µm.The experimental results confirm effective focusing and imaging capabilities of the metalens in LWIR region,thus paving the way for practical LWIR applications of met-alens technology.展开更多
A 33×33 thermo-optically tunable arrayed-waveguide-grating (AWG) has been fabricated by using the poly (2,3,4,5,6-pentafluorostyrene-co-glycidylmethacrylate) (PFS-co-GMA).The technological process of the fabricat...A 33×33 thermo-optically tunable arrayed-waveguide-grating (AWG) has been fabricated by using the poly (2,3,4,5,6-pentafluorostyrene-co-glycidylmethacrylate) (PFS-co-GMA).The technological process of the fabrication of the device is described,and the measured results are presented.The measured spacing of the wavelength channel is about 0.81 nm,the 3-dB bandwidth is about 0.35 nm,the crosstalk is about -20 dB,and the insertion loss is between 10.4 dB for the centre port and 11.9 dB for the edge port.The measured thermo-optical tunable shift is about -0.12 nm/K.The measured center wavelength is 1 545.21-1 551.81 nm in the temperature range from 10℃ to 65℃,and the tuning range is 6.6 nm.展开更多
A design of coating on the entrance surface of the beam splitters with a transparent thin film of certain refractive index and thickness was presented.For this kind of beam splitters,it was possible to realize polariz...A design of coating on the entrance surface of the beam splitters with a transparent thin film of certain refractive index and thickness was presented.For this kind of beam splitters,it was possible to realize polarization-independent beam-splitting for chosen wavelength λ with incident angle .In addition,the simulation results using the coating designable software(Auto film) were consistent with the theoretical results,and the beam splitters are not sensitive to the small errors of film-thickness and film refractive-index over a broad spectra.展开更多
A fiber laser based on broadband C-band fiber grating (CFG) and high birefringence (HiBi) fiber loop mirror (FLM) is demonstrated, which uses the comb-like reflection performance of the HiBi FLM. Under different polar...A fiber laser based on broadband C-band fiber grating (CFG) and high birefringence (HiBi) fiber loop mirror (FLM) is demonstrated, which uses the comb-like reflection performance of the HiBi FLM. Under different polarization states, different output lasers are gained by choosing the polarization states of the light in the cavity using the polarization controller. By this method, a single wavelength or dual wavelength laser beam can be output, and multi-wavelength oscillates can be achieved.展开更多
Radio-over-Fiber （RoF） technologies have been considered to be a promising solution to broadband access and ubiquitous sensing. We present a novel approach using dual-wavelength lights to suppress the nonlinear inte...Radio-over-Fiber （RoF） technologies have been considered to be a promising solution to broadband access and ubiquitous sensing. We present a novel approach using dual-wavelength lights to suppress the nonlinear intermodulation distortion in intensity-modulated RoF link both theoretically and experimentally. The system we proposed rminly consists of two Laser Diodes （LDs） at different wavelengths, a commercial available Mach-Zehnder Modulator （MZM） and a Photo Detector （PD）. More than 25 dB suppression of the Third-order Interrnodulation Distortion （IMD3） is achieved by adjusting the wavelength and opti- cal power of the laser. Besides, the output of the MZM is then sent to the photodetector via a single fiber, which simplifies the system complexity for distrbution of RF signals over long distances.展开更多
A fiber Bragg grating strain sensor,whose reflection bandwidth is insensitive to temperature,is presented.The cross-sec-tional area is designed to change linearly.Under axial stress,there is a linear relationship betw...A fiber Bragg grating strain sensor,whose reflection bandwidth is insensitive to temperature,is presented.The cross-sec-tional area is designed to change linearly.Under axial stress,there is a linear relationship between stress and average strain.Experimental results show that when temperature increases,reflection center wavelength shifts to longer wavelength,and there is a good linear relationship between center wavelength and temperature.When stress increases,reflection center wavelength shifts to longer wavelength,and reflection bandwidth increases.There are good linear relationships between reflection center wavelength and stress as well as reflection bandwidth and stress.展开更多
A novel fiber Bragg grating(FBG) sensor with simultaneous sensing of displacement and temperature is presented.The FBG is affixed on the cantilever inclinedly.The midpoint of FBG exactly coincides with the zero strain...A novel fiber Bragg grating(FBG) sensor with simultaneous sensing of displacement and temperature is presented.The FBG is affixed on the cantilever inclinedly.The midpoint of FBG exactly coincides with the zero strain layer of a rectangular beam.The vertical displacement can be measured by the broadened bandwidth of FBG as the bandwidth is insensitive to temperature,while the temperature can be measured by the center wavelength shift as the wavelength shift is insensitive to vertical displacement.With 0.1 nm spectral resolution of the analyzer,sensitivities of bandwidth-displacement and center wavelength-temperature are 0.48 nm/mm and 0.05 nm/℃,resolutions are 0.2 mm and 2.0 ℃,and sensing ranges of displacement and temperature are up to 8.5 mm and 45℃ respectively.Experimental results match theoretical analyses very well.展开更多
基金Supported by National Key R&D Program of China(2021YFA0715500)National Natural Science Foundation of China(NSFC)(12227901)+1 种基金Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB0580000)Chinese Academy of Sciences President's In-ternational Fellowship Initiative(2021PT0007).
文摘Metasurfaces in the long wave infrared(LWIR)spectrum hold great potential for applications in ther-mal imaging,atmospheric remote sensing,and target identification,among others.In this study,we designed and experimentally demonstrated a 4 mm size,all-silicon metasurface metalens with large depth of focus opera-tional across a broadband range from 9µm to 11.5µm.The experimental results confirm effective focusing and imaging capabilities of the metalens in LWIR region,thus paving the way for practical LWIR applications of met-alens technology.
文摘A 33×33 thermo-optically tunable arrayed-waveguide-grating (AWG) has been fabricated by using the poly (2,3,4,5,6-pentafluorostyrene-co-glycidylmethacrylate) (PFS-co-GMA).The technological process of the fabrication of the device is described,and the measured results are presented.The measured spacing of the wavelength channel is about 0.81 nm,the 3-dB bandwidth is about 0.35 nm,the crosstalk is about -20 dB,and the insertion loss is between 10.4 dB for the centre port and 11.9 dB for the edge port.The measured thermo-optical tunable shift is about -0.12 nm/K.The measured center wavelength is 1 545.21-1 551.81 nm in the temperature range from 10℃ to 65℃,and the tuning range is 6.6 nm.
文摘A design of coating on the entrance surface of the beam splitters with a transparent thin film of certain refractive index and thickness was presented.For this kind of beam splitters,it was possible to realize polarization-independent beam-splitting for chosen wavelength λ with incident angle .In addition,the simulation results using the coating designable software(Auto film) were consistent with the theoretical results,and the beam splitters are not sensitive to the small errors of film-thickness and film refractive-index over a broad spectra.
文摘A fiber laser based on broadband C-band fiber grating (CFG) and high birefringence (HiBi) fiber loop mirror (FLM) is demonstrated, which uses the comb-like reflection performance of the HiBi FLM. Under different polarization states, different output lasers are gained by choosing the polarization states of the light in the cavity using the polarization controller. By this method, a single wavelength or dual wavelength laser beam can be output, and multi-wavelength oscillates can be achieved.
基金Acknowledgements This work was supported by the National Basic Research Program of China under Grant No. 2012CB315705 the Hi-Tech Research and Development Program of China under Grant No. 2011AA010306+2 种基金 the National Natural Science Foundation of China under Grants No. 60736002, No. 60932004, No. 61001121, No. 61107058 and No. 61120106001 the Beijing Excellent Doctoral Thesis Project under Grant No. YB20101001301 and the Cooperation Project between Province and Ministries under Grant No. 201013090400112.
文摘Radio-over-Fiber （RoF） technologies have been considered to be a promising solution to broadband access and ubiquitous sensing. We present a novel approach using dual-wavelength lights to suppress the nonlinear intermodulation distortion in intensity-modulated RoF link both theoretically and experimentally. The system we proposed rminly consists of two Laser Diodes （LDs） at different wavelengths, a commercial available Mach-Zehnder Modulator （MZM） and a Photo Detector （PD）. More than 25 dB suppression of the Third-order Interrnodulation Distortion （IMD3） is achieved by adjusting the wavelength and opti- cal power of the laser. Besides, the output of the MZM is then sent to the photodetector via a single fiber, which simplifies the system complexity for distrbution of RF signals over long distances.
基金supported by the National Natural Science Foundation of China(Nos.60837002and61177069)the Ph.D.Programs Foundation of Ministry of Education of China(No.20090009110003)the Fundamental Research Funds for the Central Universities(No.2011YJS214)
文摘A fiber Bragg grating strain sensor,whose reflection bandwidth is insensitive to temperature,is presented.The cross-sec-tional area is designed to change linearly.Under axial stress,there is a linear relationship between stress and average strain.Experimental results show that when temperature increases,reflection center wavelength shifts to longer wavelength,and there is a good linear relationship between center wavelength and temperature.When stress increases,reflection center wavelength shifts to longer wavelength,and reflection bandwidth increases.There are good linear relationships between reflection center wavelength and stress as well as reflection bandwidth and stress.
基金supported by the National High Technology Research and Development Program of China (No.2007AA03Z413)the National Natural Science Foundation of China (No.60727004)+3 种基金the Shaanxi Province "13115" Major Scientific and Technological Innovation Works Special Project (No.708087)the Major Science and Technology Project of Ministry of Education of China (No.Z08119)the Innovation Foundation of the Petro China (No. 2008D-5006-03-08)the Shaanxi Provincial Department of Education Project (No.09JS041)
文摘A novel fiber Bragg grating(FBG) sensor with simultaneous sensing of displacement and temperature is presented.The FBG is affixed on the cantilever inclinedly.The midpoint of FBG exactly coincides with the zero strain layer of a rectangular beam.The vertical displacement can be measured by the broadened bandwidth of FBG as the bandwidth is insensitive to temperature,while the temperature can be measured by the center wavelength shift as the wavelength shift is insensitive to vertical displacement.With 0.1 nm spectral resolution of the analyzer,sensitivities of bandwidth-displacement and center wavelength-temperature are 0.48 nm/mm and 0.05 nm/℃,resolutions are 0.2 mm and 2.0 ℃,and sensing ranges of displacement and temperature are up to 8.5 mm and 45℃ respectively.Experimental results match theoretical analyses very well.
