We propose a silica-core dispersion-decreasing Bragg fiber （DDBF） of mode effective area as large as 55 μm^2 for supercontinuum （SO） generation at the pump wavelength of 1060 nm. Using a fast and simple matrix me...We propose a silica-core dispersion-decreasing Bragg fiber （DDBF） of mode effective area as large as 55 μm^2 for supercontinuum （SO） generation at the pump wavelength of 1060 nm. Using a fast and simple matrix method to model propagation in the DDBF,we have presented a general criterion to obtain the shortest length of the DDBF that would result in a broad SO spectrum. The proposed DDBF design should be amenable for reproducible fabrication through the well-developed MCVD fiber manufacturing technology and the concept has potential for realization as a practical device.展开更多
Multi-wavelength-band transmission technology based on the exploitation of the extended spectral region is considered as a potential approach to increase the transmission capacity in the deployed fiber-optic communica...Multi-wavelength-band transmission technology based on the exploitation of the extended spectral region is considered as a potential approach to increase the transmission capacity in the deployed fiber-optic communication infrastructure.The development of optical amplifiers operating in the O-,E-,S-,and U-telecom bands is an extremely important challenge for the successful implementation of this technology.Bismuth-doped fibers are of increasing interest as gain materials,which can be used to provide broadband amplification in the mentioned telecom bands.This is due to the ability of Bi ions incorporated into glass network to form bismuth active centers(BACs)with specific optical properties,which are primarily determined by the glass modifiers.In this work,the impact of the doping profiles of both Ge atoms as glass modifiers and Bi ions on the BACs formation is studied using a series of bismuth-doped fibers fabricated by the modified chemical vapor deposition(MCVD)technique.The Bi-to-BACs conversion efficiency in various spatial regions of the studied samples is presented.It is turned out that for high-Bi concentration regions,the conversion efficiency is very low(less than 10%).In addition,the relationship of the conversion efficiency to the distribution of Bi ions and/or Ge atoms is discussed.Finally,a continuous-wave laser at 1.46μm with a record slope efficiency of 80%is demonstrated using a Bi-doped fiber with confined doping profile,where the Bi-to-BACs conversion efficiency is 35%.This paper provides new information which might help to facilitate understanding of the features of Bi-doped fibers and their potentially achievable characteristics.展开更多
Background Optical fiber radioluminescence measurement(OFRLM)is a cutting-edge technique poised to play a major role in radiation detection and dosimetry.Time-resolved measurement involves capturing the temporal dynam...Background Optical fiber radioluminescence measurement(OFRLM)is a cutting-edge technique poised to play a major role in radiation detection and dosimetry.Time-resolved measurement involves capturing the temporal dynamics of light emission from scintillators,providing detailed information about radiation pulses.Objective This review aims to evaluate various scintillator materials used in time-resolved OFRLM systems and their critical importance in capturing ionizing radiation pulses.Content The article discusses the properties of scintillator materials,including organic,inorganic,and composite compositions,and highlights their unique properties and suitability for time-resolved measurements with OFRLM systems.Performance characteristics,advantages,and limitations of different scintillator materials are thoroughly reviewed.Conclusion This review provides insights into the optimal selection of scintillator materials for time-resolved OFRLM systems,offering criteria for improving their performance and facilitating advancements in radiation detection and dosimetry.展开更多
It has recently been demonstrated that Bi-doped glass optical fibers are a promising active laser medium.Various types of Bi-doped optical fibers have been developed and used to construct Bi-doped fiber lasers and opt...It has recently been demonstrated that Bi-doped glass optical fibers are a promising active laser medium.Various types of Bi-doped optical fibers have been developed and used to construct Bi-doped fiber lasers and optical amplifiers.This paper reviews the recent results regarding the luminescence properties of various Bi-doped optical fibers and the development of Bi-doped fiber lasers and optical amplifiers for the 1150 to 1550 nm spectral region.展开更多
This paper reviews a wide variety of fiber-optic microstructure(FOM)sensors,such as fiber Bragg grating(FBG)sensors,long-period fiber grating(LPFG)sensors,Fabry-Perot interferometer(FPI)sensors,Mach-Zchnder interferom...This paper reviews a wide variety of fiber-optic microstructure(FOM)sensors,such as fiber Bragg grating(FBG)sensors,long-period fiber grating(LPFG)sensors,Fabry-Perot interferometer(FPI)sensors,Mach-Zchnder interferometer(MZI)sensors,Michelson interferometer(MI)sensors,and Sagnac interferometer(SI)sensors.Each FOM sensor has been introduced in the terms of structure types,fabrication methods,and their sensing applications.In addition,the sensing characteristics of different structures under the same type of FOM sensor are compared,and the sensing characteristics of the all FOM sensors,including advantages,disadvantages,and main sensing parameters,are summarized.We also discuss the future development of FOM sensors.展开更多
A fiber-optic Raman spectrum sensor system is used for the fast diagnosis of esophageal cancer during clinical endoscopic examination.The system contains a 785nm exciting laser,a Raman fiber-optic probe with 7 large c...A fiber-optic Raman spectrum sensor system is used for the fast diagnosis of esophageal cancer during clinical endoscopic examination.The system contains a 785nm exciting laser,a Raman fiber-optic probe with 7 large core fibers and a focus lens,and a highly sensitive spectrum meter.The Raman spectrum of the tissue could be obtained within 1 second by using such a system. A signal baseline removal and denoising technology is used to improve the signal quality.A novel signal feature extraction method for differentiating the normal and esophageal cancer tissues is proposed,based on the differences in half-height width(HHW)in 1200cm^-1 to 1400cm^-1 frequency band and the ratios of the spectral integral energy between 1600cm^-1-1700cm^-1 and 1500cm^-1- 1600cm^-1 band.It shows a high specificity and effectivity for the diagnosis of esophageal cancer.展开更多
We have successfully generated a 1.3/1.4μm random fiber laser(RFL)using bismuth(Bi)-doped phosphosilicate fiber.The Bi-doped RFL has shown excellent long-term operational stability with a standard deviation of approx...We have successfully generated a 1.3/1.4μm random fiber laser(RFL)using bismuth(Bi)-doped phosphosilicate fiber.The Bi-doped RFL has shown excellent long-term operational stability with a standard deviation of approximately 0.34%over 1 h at a maximum output power of 549.30 mW,with a slope efficiency of approximately 29.21%.The Bi-doped phosphosilicate fiber offers an emission spectrum ranging from 1.28 to 1.57μm,indicating that it can be tuned within this band.Here,we demonstrated a wavelength-tuning fiber laser with a wavelength of 1.3/1.4μm,achieved through the using of a fiber Bragg grating or a tunable filter.Compared to traditional laser sources,the RFL reduces the speckle contrast of images by 11.16%.Due to its high stability,compact size,and high efficiency,this RFL is highly promising for use in biomedical imaging,communication,and sensor applications.展开更多
Three-dimensional(3D)glass chips are promising waveguide platforms for building hybrid 3D photonic circuits due to their 3D topological capabilities,large transparent windows,and low coupling dispersion.At present,the...Three-dimensional(3D)glass chips are promising waveguide platforms for building hybrid 3D photonic circuits due to their 3D topological capabilities,large transparent windows,and low coupling dispersion.At present,the key challenge in scaling down a benchtop optical system to a glass chip is the lack of precise methods for controlling the mode field and optical coupling of 3D waveguide circuits.Here,we propose an overlap-controlled multi-scan(OCMS)method based on laser-direct lithography that allows customizing the refractive index profile of 3D waveguides with high spatial precision in a variety of glasses.On the basis of this method,we achieve variable mode-field distribution,robust and broadband coupling,and thereby demonstrate dispersionless LP21-mode conversion of supercontinuum pulses with the largest deviation of<0.1 dB in coupling ratios on 210 nm broadband.This approach provides a route to achieve ultra-broadband and low-dispersion coupling in 3D photonic circuits,with overwhelming advantages over conventional planar waveguide-optic platforms for on-chip transmission and manipulation of ultrashort laser pulses and broadband supercontinuum.展开更多
Phase-sensitive optical time domain reflectometry(Ф-OTDR)is an effective way to detect vibrations and acoustic waves with high sensitivity,by interrogating coherent Rayleigh backscattering light in sensing fiber.In p...Phase-sensitive optical time domain reflectometry(Ф-OTDR)is an effective way to detect vibrations and acoustic waves with high sensitivity,by interrogating coherent Rayleigh backscattering light in sensing fiber.In particular,fiber-optic distributed acoustic sensing(DAS)based on theФ-OTDR with phase demodulation has been extensively studied and widely used in intrusion detection,borehole seismic acquisition,structure health monitoring,etc.,in recent years,with superior advantages such as long sensing range,fast response speed,wide sensing bandwidth,low operation cost and long service lifetime.Significant advances in research and development(R&D)ofФ-OTDR have been made since 2014.In this review,we present a historical review ofФ-OTDR and then summarize the recent progress ofФ-OTDR in the Fiber Optics Research Center(FORC)at University of Electronic Science and Technology of China(UESTC),which is the first group to carry out R&D ofФ-OTDR and invent ultra-sensitive DAS(uDAS)seismometer in China which is elected as one of the ten most significant technology advances of PetroChina in 2019.It can be seen that theФ-OTDR/DAS technology is currently under its rapid development stage and would reach its climax in the next 5 years.展开更多
We experimentally demonstrate ultra-high extinction ratio(ER)optical pulse modulation with an electro-optical modulator(EOM)on thin film lithium niobate(TFLN)and its application for fiber optic distributed acoustic se...We experimentally demonstrate ultra-high extinction ratio(ER)optical pulse modulation with an electro-optical modulator(EOM)on thin film lithium niobate(TFLN)and its application for fiber optic distributed acoustic sensing(DAS).An interface carrier effect leading to a relaxation-tail response of TFLN EOM is discovered,which can be well addressed by a small compensation component following the main driving signal.An ultrahigh ER>50 dB is achieved by canceling out the tailed response during pulse modulation using the EOM based on a cascaded Mach–Zehnder interferometer(MZI)structure.The modulated optical_(√)pulses are then utilized as a probe light for a DAS system,showing a sensitivity up to-62.9 dB·rad∕Hz~2(7 pε/Hz)for 2-km single-mode sensing fiber.Spatial crosstalk suppression of 24.9 dB along the fiber is also obtained when the ER is improved from 20 dB to 50 dB,clearly revealing its importance to the sensing performance.展开更多
In classical optics, interference occurs between two optical fields when they are indistinguishable from one another. The same holds true in quantum optics, where a particular experiment, the Franson interferometer, i...In classical optics, interference occurs between two optical fields when they are indistinguishable from one another. The same holds true in quantum optics, where a particular experiment, the Franson interferometer, involves the interference of a photon pair with a time-delayed version of itself. The canonical version of this interferom- eter requires that the time delay be much shorter than the coherence length of the pump used to generate the photon pair, so as to guarantee indistinguishability. However, when this time delay is comparable to the coherence length, conventional wisdom suggests that interference visibility degrades significantly. In this work, though, we show that the interference visibility can be restored through judicious temporal post-selection. Utilizing correlated photon pairs generated by a pump whose pulsewidth （460 ps） is shorter than the interferometer＇s time delay （500 ps）, we are able to observe a fringe visibility of 97.4＋4.3%. We believe this new method can be used for the encoding of high-dimensional quantum information in the temporal domain.展开更多
文摘We propose a silica-core dispersion-decreasing Bragg fiber （DDBF） of mode effective area as large as 55 μm^2 for supercontinuum （SO） generation at the pump wavelength of 1060 nm. Using a fast and simple matrix method to model propagation in the DDBF,we have presented a general criterion to obtain the shortest length of the DDBF that would result in a broad SO spectrum. The proposed DDBF design should be amenable for reproducible fabrication through the well-developed MCVD fiber manufacturing technology and the concept has potential for realization as a practical device.
文摘Multi-wavelength-band transmission technology based on the exploitation of the extended spectral region is considered as a potential approach to increase the transmission capacity in the deployed fiber-optic communication infrastructure.The development of optical amplifiers operating in the O-,E-,S-,and U-telecom bands is an extremely important challenge for the successful implementation of this technology.Bismuth-doped fibers are of increasing interest as gain materials,which can be used to provide broadband amplification in the mentioned telecom bands.This is due to the ability of Bi ions incorporated into glass network to form bismuth active centers(BACs)with specific optical properties,which are primarily determined by the glass modifiers.In this work,the impact of the doping profiles of both Ge atoms as glass modifiers and Bi ions on the BACs formation is studied using a series of bismuth-doped fibers fabricated by the modified chemical vapor deposition(MCVD)technique.The Bi-to-BACs conversion efficiency in various spatial regions of the studied samples is presented.It is turned out that for high-Bi concentration regions,the conversion efficiency is very low(less than 10%).In addition,the relationship of the conversion efficiency to the distribution of Bi ions and/or Ge atoms is discussed.Finally,a continuous-wave laser at 1.46μm with a record slope efficiency of 80%is demonstrated using a Bi-doped fiber with confined doping profile,where the Bi-to-BACs conversion efficiency is 35%.This paper provides new information which might help to facilitate understanding of the features of Bi-doped fibers and their potentially achievable characteristics.
基金TM R&D(grant number RDTC/241145)for their support of this research.
文摘Background Optical fiber radioluminescence measurement(OFRLM)is a cutting-edge technique poised to play a major role in radiation detection and dosimetry.Time-resolved measurement involves capturing the temporal dynamics of light emission from scintillators,providing detailed information about radiation pulses.Objective This review aims to evaluate various scintillator materials used in time-resolved OFRLM systems and their critical importance in capturing ionizing radiation pulses.Content The article discusses the properties of scintillator materials,including organic,inorganic,and composite compositions,and highlights their unique properties and suitability for time-resolved measurements with OFRLM systems.Performance characteristics,advantages,and limitations of different scintillator materials are thoroughly reviewed.Conclusion This review provides insights into the optimal selection of scintillator materials for time-resolved OFRLM systems,offering criteria for improving their performance and facilitating advancements in radiation detection and dosimetry.
文摘It has recently been demonstrated that Bi-doped glass optical fibers are a promising active laser medium.Various types of Bi-doped optical fibers have been developed and used to construct Bi-doped fiber lasers and optical amplifiers.This paper reviews the recent results regarding the luminescence properties of various Bi-doped optical fibers and the development of Bi-doped fiber lasers and optical amplifiers for the 1150 to 1550 nm spectral region.
基金funded by the National Natural Science Foundation of China(NCSF)(Grant Nos.51205049,51875091,and 51327806)the state 111 Project(Grant No.Bl4039).
文摘This paper reviews a wide variety of fiber-optic microstructure(FOM)sensors,such as fiber Bragg grating(FBG)sensors,long-period fiber grating(LPFG)sensors,Fabry-Perot interferometer(FPI)sensors,Mach-Zchnder interferometer(MZI)sensors,Michelson interferometer(MI)sensors,and Sagnac interferometer(SI)sensors.Each FOM sensor has been introduced in the terms of structure types,fabrication methods,and their sensing applications.In addition,the sensing characteristics of different structures under the same type of FOM sensor are compared,and the sensing characteristics of the all FOM sensors,including advantages,disadvantages,and main sensing parameters,are summarized.We also discuss the future development of FOM sensors.
基金multicenter clinical study of endoscopic diagnosis of early esophageal cancer(Grant No.SWH2016ZDCX3007)the State 111 Project(Grant No.B14039)+3 种基金Application of endoscopic minimally invasive technique in diagnosis and treatment of digestive tract injury and disease(Grant No.SWH2016ZDCX2011)Study of effect on fibroblast transdifferentiation and prevention of postoperative esophagus stenosis through regulating the TRADD(Grant No. 81470907)the National Natural Science Foundation of China(NSFC)(Grant Nos.51627806and 51875091)Application of Raman imaging in the diagnosis of gastric cancer(Grant No. cstc2015shmszx 10017).
文摘A fiber-optic Raman spectrum sensor system is used for the fast diagnosis of esophageal cancer during clinical endoscopic examination.The system contains a 785nm exciting laser,a Raman fiber-optic probe with 7 large core fibers and a focus lens,and a highly sensitive spectrum meter.The Raman spectrum of the tissue could be obtained within 1 second by using such a system. A signal baseline removal and denoising technology is used to improve the signal quality.A novel signal feature extraction method for differentiating the normal and esophageal cancer tissues is proposed,based on the differences in half-height width(HHW)in 1200cm^-1 to 1400cm^-1 frequency band and the ratios of the spectral integral energy between 1600cm^-1-1700cm^-1 and 1500cm^-1- 1600cm^-1 band.It shows a high specificity and effectivity for the diagnosis of esophageal cancer.
基金supported by the National Natural Science Foundation of China Youth Fund(No.62105272)the Fujian Natural Science Foundation Youth Project(No.2021J05016)+1 种基金the Fundamental Research Funds for the Central Universities(No.2072020109)the National Science Fund for Excellent Young Scholars(No.62022069)。
文摘We have successfully generated a 1.3/1.4μm random fiber laser(RFL)using bismuth(Bi)-doped phosphosilicate fiber.The Bi-doped RFL has shown excellent long-term operational stability with a standard deviation of approximately 0.34%over 1 h at a maximum output power of 549.30 mW,with a slope efficiency of approximately 29.21%.The Bi-doped phosphosilicate fiber offers an emission spectrum ranging from 1.28 to 1.57μm,indicating that it can be tuned within this band.Here,we demonstrated a wavelength-tuning fiber laser with a wavelength of 1.3/1.4μm,achieved through the using of a fiber Bragg grating or a tunable filter.Compared to traditional laser sources,the RFL reduces the speckle contrast of images by 11.16%.Due to its high stability,compact size,and high efficiency,this RFL is highly promising for use in biomedical imaging,communication,and sensor applications.
基金supported by the National Key R&D Program of China (No.2021YFB2802000)National Natural Science Foundation of China (Nos.U20A20211,62275233,62005164,62375246,and 62105297)+1 种基金“Pioneer”and“Leading Goose”R&D Program of Zhejiang (2023C03089)Zhejiang Provincial Natural Science Foundation (Nos.LZ23F050002 and LQ22F050022).
文摘Three-dimensional(3D)glass chips are promising waveguide platforms for building hybrid 3D photonic circuits due to their 3D topological capabilities,large transparent windows,and low coupling dispersion.At present,the key challenge in scaling down a benchtop optical system to a glass chip is the lack of precise methods for controlling the mode field and optical coupling of 3D waveguide circuits.Here,we propose an overlap-controlled multi-scan(OCMS)method based on laser-direct lithography that allows customizing the refractive index profile of 3D waveguides with high spatial precision in a variety of glasses.On the basis of this method,we achieve variable mode-field distribution,robust and broadband coupling,and thereby demonstrate dispersionless LP21-mode conversion of supercontinuum pulses with the largest deviation of<0.1 dB in coupling ratios on 210 nm broadband.This approach provides a route to achieve ultra-broadband and low-dispersion coupling in 3D photonic circuits,with overwhelming advantages over conventional planar waveguide-optic platforms for on-chip transmission and manipulation of ultrashort laser pulses and broadband supercontinuum.
基金The authors would like to thank all of the members in the FORC at UESTC for their hard work and important contributions to this workThis work was funded by the Natural Science Foundation of China(Grant Nos.41527805 and 61635005)the 111 Poject(Grant No.B14039).
文摘Phase-sensitive optical time domain reflectometry(Ф-OTDR)is an effective way to detect vibrations and acoustic waves with high sensitivity,by interrogating coherent Rayleigh backscattering light in sensing fiber.In particular,fiber-optic distributed acoustic sensing(DAS)based on theФ-OTDR with phase demodulation has been extensively studied and widely used in intrusion detection,borehole seismic acquisition,structure health monitoring,etc.,in recent years,with superior advantages such as long sensing range,fast response speed,wide sensing bandwidth,low operation cost and long service lifetime.Significant advances in research and development(R&D)ofФ-OTDR have been made since 2014.In this review,we present a historical review ofФ-OTDR and then summarize the recent progress ofФ-OTDR in the Fiber Optics Research Center(FORC)at University of Electronic Science and Technology of China(UESTC),which is the first group to carry out R&D ofФ-OTDR and invent ultra-sensitive DAS(uDAS)seismometer in China which is elected as one of the ten most significant technology advances of PetroChina in 2019.It can be seen that theФ-OTDR/DAS technology is currently under its rapid development stage and would reach its climax in the next 5 years.
基金Center-initiated Research Project of Zhejiang Laboratory(K2022ME0AL04)National Key Research and Development Program of China(2021ZD0109904)+1 种基金National Natural Science Foundation of China(62105301)Key Research Project of Zhejiang Laboratory(2020ME0AD02)。
文摘We experimentally demonstrate ultra-high extinction ratio(ER)optical pulse modulation with an electro-optical modulator(EOM)on thin film lithium niobate(TFLN)and its application for fiber optic distributed acoustic sensing(DAS).An interface carrier effect leading to a relaxation-tail response of TFLN EOM is discovered,which can be well addressed by a small compensation component following the main driving signal.An ultrahigh ER>50 dB is achieved by canceling out the tailed response during pulse modulation using the EOM based on a cascaded Mach–Zehnder interferometer(MZI)structure.The modulated optical_(√)pulses are then utilized as a probe light for a DAS system,showing a sensitivity up to-62.9 dB·rad∕Hz~2(7 pε/Hz)for 2-km single-mode sensing fiber.Spatial crosstalk suppression of 24.9 dB along the fiber is also obtained when the ER is improved from 20 dB to 50 dB,clearly revealing its importance to the sensing performance.
文摘In classical optics, interference occurs between two optical fields when they are indistinguishable from one another. The same holds true in quantum optics, where a particular experiment, the Franson interferometer, involves the interference of a photon pair with a time-delayed version of itself. The canonical version of this interferom- eter requires that the time delay be much shorter than the coherence length of the pump used to generate the photon pair, so as to guarantee indistinguishability. However, when this time delay is comparable to the coherence length, conventional wisdom suggests that interference visibility degrades significantly. In this work, though, we show that the interference visibility can be restored through judicious temporal post-selection. Utilizing correlated photon pairs generated by a pump whose pulsewidth （460 ps） is shorter than the interferometer＇s time delay （500 ps）, we are able to observe a fringe visibility of 97.4＋4.3%. We believe this new method can be used for the encoding of high-dimensional quantum information in the temporal domain.
