Optical fiber technology has changed the world by enabling extraordinary growth in world-wide communications and sensing.The rapid development and wide deployment of optical fiber sensors are driven by their excellent...Optical fiber technology has changed the world by enabling extraordinary growth in world-wide communications and sensing.The rapid development and wide deployment of optical fiber sensors are driven by their excellent sensing performance with outstanding flexibility,functionality,and versatility.Notably,the research on specialty optical fibers is playing a critical role in enabling and proliferating the optical fiber sensing applications.This paper overviews recent developments in specialty optical fibers and their sensing applications.The specialty optical fibers are reviewed based on their innovations in special structures,special materials,and technologies to realize lab in/on a fiber.An overview of sensing applications in various fields is presented.The prospects and emerging research areas of specialty optical fibers are also discussed.展开更多
This paper presents a novel way to improve Transmission Control Protocol (TCP) performance of the users at the edge areas of the macro cells in Long Term Evolution Advanced (LTE-A) systems. Previous works on improving...This paper presents a novel way to improve Transmission Control Protocol (TCP) performance of the users at the edge areas of the macro cells in Long Term Evolution Advanced (LTE-A) systems. Previous works on improving wireless TCP performance are reviewed and current considerations on TCP in LTE-A are explained. However, those solutions are neither too complex nor limited to some presuppositions which are too restricting for the deployment of LTE-A networks. In this paper a substituted TCP acknowledgement transmission scheme based on Automatic Repeat reQuest (ARQ) information in layer 2 is proposed. The simulation result shows that the proposed method can reduce the delay and improve the throughput of the edging users of the cell, as well as reducing radio resources in LTE-A macro cells.展开更多
A new hybrid WDM/TDM passive optical network （PON） implemented by using all-optical wavelength converters （AOWCs） is proposed. The AOWCs are based on the cross-gain modulation （XGM） effect of the semiconductor o...A new hybrid WDM/TDM passive optical network （PON） implemented by using all-optical wavelength converters （AOWCs） is proposed. The AOWCs are based on the cross-gain modulation （XGM） effect of the semiconductor optical amplifier （SOA）. Moreover, the feasibility of this sys- tem is experimentally demonstrated by evaluating the impacts of the optical wavelength conversion, time domain waveforms, eye diagrams and bit-error-rate （BER） in AOWC. The results show that the proposal will be a promising solution for the next generation access networks.展开更多
With the proposal of a“smart battery,”real-time sensing by rechargeable batteries has become progressively more important in both fundamental research and practical applications.However,many traditional sensing tech...With the proposal of a“smart battery,”real-time sensing by rechargeable batteries has become progressively more important in both fundamental research and practical applications.However,many traditional sensing technologies suffer from low sensitivity,large size,and electromagnetic interference problems,rendering them unusable in the harsh and complicated electrochemical environments of batteries.The optical sensor is an alternative approach to realize multiple-parameter,multiple-point measurements simultaneously.Thus,it has garnered significant attention.Through analyzing these measured parameters,the state of interest can be decoded to monitor a battery's health.This review summarizes current progress in optical sensing techniques for batteries with respect to various sensing parameters,discussing the current limitations of optical fiber sensors as well as directions for their future development.展开更多
In this paper,we present a fast mode decomposition method for few-mode fibers,utilizing a lightweight neural network called MobileNetV3-Light.This method can quickly and accurately predict the amplitude and phase info...In this paper,we present a fast mode decomposition method for few-mode fibers,utilizing a lightweight neural network called MobileNetV3-Light.This method can quickly and accurately predict the amplitude and phase information of different modes,enabling us to fully characterize the optical field without the need for expensive experimental equipment.We train the MobileNetV3-Light using simulated near-field optical field maps,and evaluate its performance using both simulated and reconstructed near-field optical field maps.To validate the effectiveness of this method,we conduct mode decomposition experiments on a few-mode fiber supporting six linear polarization(LP)modes(LP01,LP11e,LP11o,LP21e,LP21o,LP02).The results demonstrate a remarkable average correlation of 0.9995 between our simulated and reconstructed near-field lightfield maps.And the mode decomposition speed is about 6 ms per frame,indicating its powerful real-time processing capability.In addition,the proposed network model is compact,with a size of only 6.5 MB,making it well suited for deployment on portable mobile devices.展开更多
Continuous pulse wave signals monitoring is the essential basis for clinical cardiovascular diagnosis and treatment.Recent researches show the majority of current electronic pulse sensors usually face challenges in el...Continuous pulse wave signals monitoring is the essential basis for clinical cardiovascular diagnosis and treatment.Recent researches show the majority of current electronic pulse sensors usually face challenges in electrical safety concern,poor durability and demanding precision in position alignment.Thus,a highly sensitive,inherently electrical safe,robust and alignment-free device is highly desired.Here,we present a wearable alignment-free microfber-based sensor chip(AFMSC)for precise vital signs monitoring and cardiovascular health assessment.The AFMSC comprises an optical micro/nano fber sensor(MNF)and a fexible soft liquid sac while the MNF sensor is used to perceive the physiological signals and the liquid sac is used to eliminate the misalignment.The real-time and accurate monitoring of the pulse signals was realized by tracking the optical power variation of transmitted light from MNF.Then,the cardiovascular vital signs extracted from radial artery pulse signals were used to evaluate cardiovascular health condition and the results were in accordance with human physiological characteristics.Moreover,the pulse signals from diferent arterial area,the respiration signals from chest and the radial pulse signals before and after exercise were detected and analyzed.The non-invasive,continuous and accurate monitoring of cardiovascular health based on the reported wearable and alignment-free device is promising in both ftness monitoring and medical diagnostics for cardiovascular disease prevention and diagnosis.展开更多
The recent research progress in the key device and technology of the fiber optic sensor network （FOSN） is introduced in this paper. An architecture of the sensor optical passive network （SPON）, by employing hybrid...The recent research progress in the key device and technology of the fiber optic sensor network （FOSN） is introduced in this paper. An architecture of the sensor optical passive network （SPON）, by employing hybrid wavelength division multiplexing/time division multiplexing （WDM/TDM） techniques similar to the fiber communication passive optical network （PON）, is proposed. The network topology scheme of a hybrid TDM/WDM/FDM （frequency division multiplexing） three-dimension fiber optic sensing system for achieving ultra-large capacity, long distance, and high resolution sensing performance is performed and analyzed. As the most important device of the FOSN, several kinds of light source are developed, including the wideband multi-wavelength fiber laser operating at C band, switchable and tunable 2 μm multi-wavelength fiber lasers, ultra-fast mode-locked fiber laser, as well as the optical wideband chaos source, which have very good application prospects in the FOSN. Meanwhile, intelligent management techniques for the FOSN including wideband spectrum demodulation of the sensing signals and real-time fault monitoring of fiber links are presented. Moreover, several typical applications of the FOSN are also discussed, such as the fiber optic gas sensing network, fiber optic acoustic sensing network, and strain/dynamic strain sensing network.展开更多
To achieve dexterous motion controlling of robot,the sensors that function like human neurons for motion perception are essential.In this work,a silica microfber probe-based optical neuron(MPON)for robot fnger motion ...To achieve dexterous motion controlling of robot,the sensors that function like human neurons for motion perception are essential.In this work,a silica microfber probe-based optical neuron(MPON)for robot fnger motion detection is proposed.The silica microfber probe was fabricated by snapping a biconical silica optical microfber that drawn from the standard optical fbre.Then it was embedded into thin polydimethylsiloxane(PDMS)to detect and recognize motions of robotic fnger.Specifcally,a PDMS-Tefon-Microfber-Tefon-PDMS composite structure was prepared to protect the waveguide structure of silica microfber probe and avoid the environmental pollution.With the help of this composite structure,the proposed MPON achieved the accurate measurement of bending angle with large range and fast response.The repeatability and stability of MPON were also investigated.Additionally,diferent fnger motions were successfully distinguished through observing the output power variation of MPON.The proposed MPON could serve as the perceptron of robot hand,which could be applied in dexterous gesture control even human machine interaction.展开更多
In this paper, we proposed a novel modulation format identification method for square M-quadrature amplitude modulation (M-QAM) signals which is based on amplitude histogram space of the incoming data after analog-to-...In this paper, we proposed a novel modulation format identification method for square M-quadrature amplitude modulation (M-QAM) signals which is based on amplitude histogram space of the incoming data after analog-to-digital conversion, chromatic dispersion com-pensation at the receiver. We demonstrated the identifica-tion of quadrature phase-shift keying (QPSK), 16-QAM, 64-QAM formats with an amplitude histogram space. Simulation results show that it achieve 100% identification accuracy when the incoming signal OSNR is 14 dB to identify the modulation format of QPSK, 16-QAM, and 64-QAM signals in digital coherent systems. The method has low complexity and small delay.展开更多
A distributed access scheme using optical add/drop multiplexers （OADMs） for long reach hybrid wavelength division multiplexing and time division multiplexing passive optical networks （WDM-TDM PONs） is proposed and...A distributed access scheme using optical add/drop multiplexers （OADMs） for long reach hybrid wavelength division multiplexing and time division multiplexing passive optical networks （WDM-TDM PONs） is proposed and demonstrated. Colorless operations are implemented by using commercially available reflective semiconductor optical amplifiers （RSOAs） at both the center office （CO） and the customer side. Four 1.25-Gb/s channels are successfully transmitted over 80-km single-mode fiber with four OADMs. The dynamic input power range of the RSOA is also investigated. Compared with traditional access schemes, the proposed scheme could cover the area along the feed fiber with no blind zone. The experimental results show that it could be an ideal solution for the next generation access networks.展开更多
Pilot data aided feed forward （PAFF） carrier recovery is essential for phase noise tracking in coherent optical receivers. This paper describes a new PAFF system based on new pilot arrangement and maximum likelihood...Pilot data aided feed forward （PAFF） carrier recovery is essential for phase noise tracking in coherent optical receivers. This paper describes a new PAFF system based on new pilot arrangement and maximum likelihood （ML） to estimate the phase jitter in coherent receiver- induced by local oscillator＇s lasers and sampling clock errors. Square M-ary quadrature amplitude modulation （M-QAM） （4, 16, 64, and 256） schemes were used. A detailed mathematical description of the method was presented. The system performance was evaluated through numerical simulations and compared to those with noisefree receiver （ideal receiver） and feed forward without ML. The simulation results show that PAFF performs near the expected ideal phase recovery. Results clearly suggest that ML significantly improves the tolerance of phase error variance. From bit error rate （BER） sensibility evaluation, it was clearly observed that the new estimation method performs better with a 4-QAM （or quadrature phase shift keying （QPSK）） format compared to three others square QAM schemes. Analog to digital converter （ADC） resolution effect on the system performance was analyzed in terms of Q-factor. Finite resolution effect on 4-QAM is negligible while it negatively affects the system performance when M increases.展开更多
A theoretical introduction of saturable absorber based on standing-wave saturation effects as a transient fiber Bragg grating （FBG） was presented. The central wavelength of the transient FBG was located in 2 μm. Th...A theoretical introduction of saturable absorber based on standing-wave saturation effects as a transient fiber Bragg grating （FBG） was presented. The central wavelength of the transient FBG was located in 2 μm. The factors affecting the bandwidth and the reflectivity of the transient FBG were analyzed. The linewidth and reflectiv- ity as the function of doped fiber length and doping concentration were correspondingly simulated by Matlab software. It was found that the larger the doping concentration and the fiber length were, the smaller the bandwidth was. These results suggest that the performance of the transient FBG can be optimized by choosing the appropriate length of doped fiber and the larger doping concentration, which can be used as a reference for the narrow-linewidth fiber laser around 2 μm.展开更多
We propose and experimentally demonstrate a novel physical layer encryption scheme for high-speed optical communication. A 10 Gb/s on-off keying signal is secretly transmitted over 100 km standard single-mode fiber.Th...We propose and experimentally demonstrate a novel physical layer encryption scheme for high-speed optical communication. A 10 Gb/s on-off keying signal is secretly transmitted over 100 km standard single-mode fiber.The intensity-modulated message is secured by the encryption mechanism, which is composed of an external noise source and an internal time-delayed feedback loop. The external noise serves as an entropy source with sufficient randomness. The feedback loop structure in the transmitter introduces a time-domain encryption key space, and a corresponding open-loop configuration at the receiver side is used for synchronization and decryption.Experiment results show the effectiveness of the proposed scheme. For a legitimate terminal, bit error rate below10-8 can be obtained. Decryption degradations with the mismatch of different hardware parameters are researched. The time delay in the feedback loop provides a sensitive encryption key. For other hardware parameters,the system is robust enough for synchronization. Meanwhile, the time-delay signature of the loop is able to be well concealed by the external noise. Moreover, the proposed scheme can support density wavelength division multiplexing transmission with a relatively simple structure. This work also provides a new concept to establish optical secure communication by combining a time-delayed feedback chaotic system and random noise.展开更多
In this Letter, a low-frequency acoustic sensor based on an extrinsic Fabry–Pérot(FP) interferometer with a silicon nitride(Si3N4) membrane is demonstrated. Using micromachining techniques, the 800 nm thick Si3N...In this Letter, a low-frequency acoustic sensor based on an extrinsic Fabry–Pérot(FP) interferometer with a silicon nitride(Si3N4) membrane is demonstrated. Using micromachining techniques, the 800 nm thick Si3N4 membrane is deposited on an 8 mm × 8 mm × 400 μm silicon(Si) substrate. All the assembly procedures of the sensor are focused on the substrate to avoid any damage to the membrane itself, compared to general membrane transfer methods. The frequency response of the proposed sensor is discussed theoretically and experimentally demonstrated. The sensor exhibits an excellent flat response to the tested acoustic frequency range of 1 Hz to 250 Hz. The phase sensitivity is around-152 dB re 1 rad/μPa with sensitivity fluctuation less than 0.8 dB.The frequency response characteristic shows a promising potential of the sensor in low-frequency acoustic signal sensing applications.展开更多
We have investigated the whole polarization-extinction-ratio(PER) spectrum and annealing properties of45°-tilted fiber gratings(45°-TFGs). Experimental results show the PER spectrum of 45°-TFGs is a Gau...We have investigated the whole polarization-extinction-ratio(PER) spectrum and annealing properties of45°-tilted fiber gratings(45°-TFGs). Experimental results show the PER spectrum of 45°-TFGs is a Gaussianlike profile and covers a 540 nm bandwidth from 1260 to 1800 nm, in which the bandwidth with PER greater than 10 dB is over 250 nm. The output polarization distribution of 45°-TFGs was analyzed by employing a bulk linear polarizer, and the results show a perfect figure "8", which indicates that the 45°-TFG is a type of linear polarizer. Moreover, the annealing property of 45°-TFGs was measured up to 700°C, in which the PER of the grating started to decrease at 300°C and reached the minimum at 700°C. Based on these results, the 45°-TFGs can be used as an ultra-wide bandwidth in-fiber polarizing device.展开更多
This Letter shows the Vernier effect based on two segments of PANDA polarization maintaining fiber(PMF),whose lengths are 28 and 23 cm, respectively. The two PMFs are spliced together, and the angle between the fast a...This Letter shows the Vernier effect based on two segments of PANDA polarization maintaining fiber(PMF),whose lengths are 28 and 23 cm, respectively. The two PMFs are spliced together, and the angle between the fast axes is set to 45°. This cascaded PMF is inserted in a Sagnac loop to form an interferometer that can generate the Vernier effect. The spectrum consists of finesse fringe and envelope and realizes simultaneous measurement of strain and temperature. The envelope can provide strain and temperature sensitivities of 58.0 pm/με and -1.05 nm/℃. The finesse fringe provides sensitivities of 5.9 pm/με and -1.36 nm/℃.展开更多
We propose a high sensitivity sensor based on a mode number-encoded multi-longitudinal mode fiber laser. The fiber laser incorporates a uniform fiber Bragg grating （FBG） and a fiber Fabry-Perot interferometer （FFPI...We propose a high sensitivity sensor based on a mode number-encoded multi-longitudinal mode fiber laser. The fiber laser incorporates a uniform fiber Bragg grating （FBG） and a fiber Fabry-Perot interferometer （FFPI） as sensitive components in the cavity. The sensor counts the number of longitudinal modes （NLM） of fiber laser, which is caused by the mismatch between the reflection band of FBG and the transmission band of FFPI resulting from the application of external perturbation to the FBG. An electrical spectrum analyzer is adopted to analyze the NLM. The strain sensor is experimentally demonstrated to have sensi- tivity of as high as 0.02 με/mode.展开更多
In this Letter, we experimentally demonstrate a full-duplex transmission system of IEEE 802.11ac-compliant multiple-input multiple-output （MIMO） signals over a 2-kin 7-core fiber for in-building wireless local-area ...In this Letter, we experimentally demonstrate a full-duplex transmission system of IEEE 802.11ac-compliant multiple-input multiple-output （MIMO） signals over a 2-kin 7-core fiber for in-building wireless local-area net- work （WLAN） distributed antenna systems. For full-duplex 3 x 3 MIMO demonstration, the crosstalk impacts of both fiber-transmission-only and optic-wireless transmission situation are evaluated. The results indicate that the impact of crosstalk on radio-over-fiber （ROF） link performance is not significant and the quality of the cascaded multi-core fiber and wireless channel is mainly determined by the wireless part. To further improve the system capacity, polarization multiplexing （PolMux） technology is employed to achieve a full-duplex 6 × 6 MIMO over a single 7-core fiber. Although employing the PolMux method will slightly decrease the EVM and condition number performance as opposed to a non-PolMux MCF system, it is still a competitive solution in large optical connection demand scenarios that require a low cost.展开更多
With the increasing capacity demands fueled by the emerging heterogeneous and bandwidth-intensive applica- tions, such as cloud computing, 4K/8K videos, and virtual reality （VR）, the need for low-cost, power-efficie...With the increasing capacity demands fueled by the emerging heterogeneous and bandwidth-intensive applica- tions, such as cloud computing, 4K/8K videos, and virtual reality （VR）, the need for low-cost, power-efficient, and high-density short-reach optical interconnects operating at 100 Gb/s and beyond has drawn significant research efforts.展开更多
In this Letter, an alternative solution is proposed and demonstrated for simultaneous measurement of axial strain and temperature. This sensor consists of two twisted points on a commercial single mode fiber introduce...In this Letter, an alternative solution is proposed and demonstrated for simultaneous measurement of axial strain and temperature. This sensor consists of two twisted points on a commercial single mode fiber introduced by flame-heated and rotation treatment. The fabrication process modifies the geometrical configuration and refractive index of the fiber. Different cladding modes are excited at the first twisted point, and part of them are coupled back to the fiber core at the second twisted point. Experimental results show distinct sensitivities of 34.9 pm/με with 49.23 pm/℃ and -36.19 pm/με with 62.99 pm/℃ for the two selected destructive interference wavelengths.展开更多
基金We are grateful for financial supports from Special Funds for the Major Fields of Colleges and Universities by the Department of Education of Guangdong Province(2021ZDZX1023)Natural Science Foundation of Guangdong Province(No.2022A1515011434)+4 种基金Stable Support Program for Higher Education Institutions from Shenzhen Science,Technology&Innovation Commission(20200925162216001)Guangdong Basic and Applied Basic Research Foundation(2021B1515120013)Open Fund of State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications,No.IPOC2020A002)The Open Projects Foundation of State Key Laboratory of Optical Fiber and Cable Manufacture Technology(No.SKLD2105)General Program of Shenzhen Science,Technology&Innovation Commission(JCYJ20220530113811026).
文摘Optical fiber technology has changed the world by enabling extraordinary growth in world-wide communications and sensing.The rapid development and wide deployment of optical fiber sensors are driven by their excellent sensing performance with outstanding flexibility,functionality,and versatility.Notably,the research on specialty optical fibers is playing a critical role in enabling and proliferating the optical fiber sensing applications.This paper overviews recent developments in specialty optical fibers and their sensing applications.The specialty optical fibers are reviewed based on their innovations in special structures,special materials,and technologies to realize lab in/on a fiber.An overview of sensing applications in various fields is presented.The prospects and emerging research areas of specialty optical fibers are also discussed.
基金Partly supported by the Key Project of National Natural Science Foundation of China(No.61231007)863 Hi Tech R&D Program of China(No.2012AA121604)ISTCP(No.2012DFG12010)
文摘This paper presents a novel way to improve Transmission Control Protocol (TCP) performance of the users at the edge areas of the macro cells in Long Term Evolution Advanced (LTE-A) systems. Previous works on improving wireless TCP performance are reviewed and current considerations on TCP in LTE-A are explained. However, those solutions are neither too complex nor limited to some presuppositions which are too restricting for the deployment of LTE-A networks. In this paper a substituted TCP acknowledgement transmission scheme based on Automatic Repeat reQuest (ARQ) information in layer 2 is proposed. The simulation result shows that the proposed method can reduce the delay and improve the throughput of the edging users of the cell, as well as reducing radio resources in LTE-A macro cells.
文摘A new hybrid WDM/TDM passive optical network （PON） implemented by using all-optical wavelength converters （AOWCs） is proposed. The AOWCs are based on the cross-gain modulation （XGM） effect of the semiconductor optical amplifier （SOA）. Moreover, the feasibility of this sys- tem is experimentally demonstrated by evaluating the impacts of the optical wavelength conversion, time domain waveforms, eye diagrams and bit-error-rate （BER） in AOWC. The results show that the proposal will be a promising solution for the next generation access networks.
基金the support from the National Key R&D Program of China(2021YFB2400300)the National Natural Science Foundation of China(Nos.51972131 and 5202780089).
文摘With the proposal of a“smart battery,”real-time sensing by rechargeable batteries has become progressively more important in both fundamental research and practical applications.However,many traditional sensing technologies suffer from low sensitivity,large size,and electromagnetic interference problems,rendering them unusable in the harsh and complicated electrochemical environments of batteries.The optical sensor is an alternative approach to realize multiple-parameter,multiple-point measurements simultaneously.Thus,it has garnered significant attention.Through analyzing these measured parameters,the state of interest can be decoded to monitor a battery's health.This review summarizes current progress in optical sensing techniques for batteries with respect to various sensing parameters,discussing the current limitations of optical fiber sensors as well as directions for their future development.
基金supported by the Scientific Research Fund of Hunan Provincial Education Department of China(No.22B0324)the Natural Science Foundation of Hunan Province of China(No.2020JJ5606)。
文摘In this paper,we present a fast mode decomposition method for few-mode fibers,utilizing a lightweight neural network called MobileNetV3-Light.This method can quickly and accurately predict the amplitude and phase information of different modes,enabling us to fully characterize the optical field without the need for expensive experimental equipment.We train the MobileNetV3-Light using simulated near-field optical field maps,and evaluate its performance using both simulated and reconstructed near-field optical field maps.To validate the effectiveness of this method,we conduct mode decomposition experiments on a few-mode fiber supporting six linear polarization(LP)modes(LP01,LP11e,LP11o,LP21e,LP21o,LP02).The results demonstrate a remarkable average correlation of 0.9995 between our simulated and reconstructed near-field lightfield maps.And the mode decomposition speed is about 6 ms per frame,indicating its powerful real-time processing capability.In addition,the proposed network model is compact,with a size of only 6.5 MB,making it well suited for deployment on portable mobile devices.
基金This work was supported by the National Science Fund of China for Excellent Young Scholars(No.61922033)the Science Found for Creative Research Groups of the Natural Science Foundation of Hubei(No.2018CFA004)the Innovation Fund of WNLO.
文摘Continuous pulse wave signals monitoring is the essential basis for clinical cardiovascular diagnosis and treatment.Recent researches show the majority of current electronic pulse sensors usually face challenges in electrical safety concern,poor durability and demanding precision in position alignment.Thus,a highly sensitive,inherently electrical safe,robust and alignment-free device is highly desired.Here,we present a wearable alignment-free microfber-based sensor chip(AFMSC)for precise vital signs monitoring and cardiovascular health assessment.The AFMSC comprises an optical micro/nano fber sensor(MNF)and a fexible soft liquid sac while the MNF sensor is used to perceive the physiological signals and the liquid sac is used to eliminate the misalignment.The real-time and accurate monitoring of the pulse signals was realized by tracking the optical power variation of transmitted light from MNF.Then,the cardiovascular vital signs extracted from radial artery pulse signals were used to evaluate cardiovascular health condition and the results were in accordance with human physiological characteristics.Moreover,the pulse signals from diferent arterial area,the respiration signals from chest and the radial pulse signals before and after exercise were detected and analyzed.The non-invasive,continuous and accurate monitoring of cardiovascular health based on the reported wearable and alignment-free device is promising in both ftness monitoring and medical diagnostics for cardiovascular disease prevention and diagnosis.
基金These works are supported by a grant from the Sub-Project of the Major Program of the National Natural Science Foundation of China （No. 61290315）, the National Natural Science Foundation of China （No. 61275083, 61275004, and 61404056）, the National Key Foundation of Exploring Scientific Instrument of China （No. 2013YQ16048707）, and the Fundamental Research Funds for the Central Universities （HUST： No. 2014CG002, and 2014QNRC005）. Much appreciation should be given to the students, Zhinlin Xu, Yiyang Luo, Fan Ai, Wei Yang, Enci Chen, Shun Wang ,Shui Zhao, Li Liu, Hao Liao, Xin Fu, Shun Wang, Wei Yang, Wang Yang, and Mingren Su.
文摘The recent research progress in the key device and technology of the fiber optic sensor network （FOSN） is introduced in this paper. An architecture of the sensor optical passive network （SPON）, by employing hybrid wavelength division multiplexing/time division multiplexing （WDM/TDM） techniques similar to the fiber communication passive optical network （PON）, is proposed. The network topology scheme of a hybrid TDM/WDM/FDM （frequency division multiplexing） three-dimension fiber optic sensing system for achieving ultra-large capacity, long distance, and high resolution sensing performance is performed and analyzed. As the most important device of the FOSN, several kinds of light source are developed, including the wideband multi-wavelength fiber laser operating at C band, switchable and tunable 2 μm multi-wavelength fiber lasers, ultra-fast mode-locked fiber laser, as well as the optical wideband chaos source, which have very good application prospects in the FOSN. Meanwhile, intelligent management techniques for the FOSN including wideband spectrum demodulation of the sensing signals and real-time fault monitoring of fiber links are presented. Moreover, several typical applications of the FOSN are also discussed, such as the fiber optic gas sensing network, fiber optic acoustic sensing network, and strain/dynamic strain sensing network.
基金This work was supported by the National Natural Science Foundation of China(NSFC)(Grant Number:61922033 and 61775072)the Innovation Fund of Wuhan National Laboratory for Optoelectronics(WNLO).
文摘To achieve dexterous motion controlling of robot,the sensors that function like human neurons for motion perception are essential.In this work,a silica microfber probe-based optical neuron(MPON)for robot fnger motion detection is proposed.The silica microfber probe was fabricated by snapping a biconical silica optical microfber that drawn from the standard optical fbre.Then it was embedded into thin polydimethylsiloxane(PDMS)to detect and recognize motions of robotic fnger.Specifcally,a PDMS-Tefon-Microfber-Tefon-PDMS composite structure was prepared to protect the waveguide structure of silica microfber probe and avoid the environmental pollution.With the help of this composite structure,the proposed MPON achieved the accurate measurement of bending angle with large range and fast response.The repeatability and stability of MPON were also investigated.Additionally,diferent fnger motions were successfully distinguished through observing the output power variation of MPON.The proposed MPON could serve as the perceptron of robot hand,which could be applied in dexterous gesture control even human machine interaction.
基金the National Natural Science Foundation of China (Grant Nos. 61575071, and 61331010).
文摘In this paper, we proposed a novel modulation format identification method for square M-quadrature amplitude modulation (M-QAM) signals which is based on amplitude histogram space of the incoming data after analog-to-digital conversion, chromatic dispersion com-pensation at the receiver. We demonstrated the identifica-tion of quadrature phase-shift keying (QPSK), 16-QAM, 64-QAM formats with an amplitude histogram space. Simulation results show that it achieve 100% identification accuracy when the incoming signal OSNR is 14 dB to identify the modulation format of QPSK, 16-QAM, and 64-QAM signals in digital coherent systems. The method has low complexity and small delay.
基金supported by the National "863" program of China (No. 2007AA01Z229)the National Basic Research Program of China (No. 2010CB328300)
文摘A distributed access scheme using optical add/drop multiplexers （OADMs） for long reach hybrid wavelength division multiplexing and time division multiplexing passive optical networks （WDM-TDM PONs） is proposed and demonstrated. Colorless operations are implemented by using commercially available reflective semiconductor optical amplifiers （RSOAs） at both the center office （CO） and the customer side. Four 1.25-Gb/s channels are successfully transmitted over 80-km single-mode fiber with four OADMs. The dynamic input power range of the RSOA is also investigated. Compared with traditional access schemes, the proposed scheme could cover the area along the feed fiber with no blind zone. The experimental results show that it could be an ideal solution for the next generation access networks.
文摘Pilot data aided feed forward （PAFF） carrier recovery is essential for phase noise tracking in coherent optical receivers. This paper describes a new PAFF system based on new pilot arrangement and maximum likelihood （ML） to estimate the phase jitter in coherent receiver- induced by local oscillator＇s lasers and sampling clock errors. Square M-ary quadrature amplitude modulation （M-QAM） （4, 16, 64, and 256） schemes were used. A detailed mathematical description of the method was presented. The system performance was evaluated through numerical simulations and compared to those with noisefree receiver （ideal receiver） and feed forward without ML. The simulation results show that PAFF performs near the expected ideal phase recovery. Results clearly suggest that ML significantly improves the tolerance of phase error variance. From bit error rate （BER） sensibility evaluation, it was clearly observed that the new estimation method performs better with a 4-QAM （or quadrature phase shift keying （QPSK）） format compared to three others square QAM schemes. Analog to digital converter （ADC） resolution effect on the system performance was analyzed in terms of Q-factor. Finite resolution effect on 4-QAM is negligible while it negatively affects the system performance when M increases.
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 61275083, 61290315）.
文摘A theoretical introduction of saturable absorber based on standing-wave saturation effects as a transient fiber Bragg grating （FBG） was presented. The central wavelength of the transient FBG was located in 2 μm. The factors affecting the bandwidth and the reflectivity of the transient FBG were analyzed. The linewidth and reflectiv- ity as the function of doped fiber length and doping concentration were correspondingly simulated by Matlab software. It was found that the larger the doping concentration and the fiber length were, the smaller the bandwidth was. These results suggest that the performance of the transient FBG can be optimized by choosing the appropriate length of doped fiber and the larger doping concentration, which can be used as a reference for the narrow-linewidth fiber laser around 2 μm.
基金National Key R&D Program of China(2018YFB1801304)State Key Laboratory of Advanced Optical Communication Systems and Networks(2019GZKF7)+1 种基金National Natural Science Foundation of China(61505061,61675083)Key Project of RD Program of Hubei Province(2017AAA046)
文摘We propose and experimentally demonstrate a novel physical layer encryption scheme for high-speed optical communication. A 10 Gb/s on-off keying signal is secretly transmitted over 100 km standard single-mode fiber.The intensity-modulated message is secured by the encryption mechanism, which is composed of an external noise source and an internal time-delayed feedback loop. The external noise serves as an entropy source with sufficient randomness. The feedback loop structure in the transmitter introduces a time-domain encryption key space, and a corresponding open-loop configuration at the receiver side is used for synchronization and decryption.Experiment results show the effectiveness of the proposed scheme. For a legitimate terminal, bit error rate below10-8 can be obtained. Decryption degradations with the mismatch of different hardware parameters are researched. The time delay in the feedback loop provides a sensitive encryption key. For other hardware parameters,the system is robust enough for synchronization. Meanwhile, the time-delay signature of the loop is able to be well concealed by the external noise. Moreover, the proposed scheme can support density wavelength division multiplexing transmission with a relatively simple structure. This work also provides a new concept to establish optical secure communication by combining a time-delayed feedback chaotic system and random noise.
基金supported by the National Key R&D Program of China (No. 2018YFF01011800)the National Natural Science Foundation of China (No. 61775070)the Fundamental Research Funds for the Central Universities (Nos. 2017KFYXJJ032 and 2019kfyXMBZ052)
文摘In this Letter, a low-frequency acoustic sensor based on an extrinsic Fabry–Pérot(FP) interferometer with a silicon nitride(Si3N4) membrane is demonstrated. Using micromachining techniques, the 800 nm thick Si3N4 membrane is deposited on an 8 mm × 8 mm × 400 μm silicon(Si) substrate. All the assembly procedures of the sensor are focused on the substrate to avoid any damage to the membrane itself, compared to general membrane transfer methods. The frequency response of the proposed sensor is discussed theoretically and experimentally demonstrated. The sensor exhibits an excellent flat response to the tested acoustic frequency range of 1 Hz to 250 Hz. The phase sensitivity is around-152 dB re 1 rad/μPa with sensitivity fluctuation less than 0.8 dB.The frequency response characteristic shows a promising potential of the sensor in low-frequency acoustic signal sensing applications.
基金supported by the National Natural Science Foundation of China(No.61505244)the Fundamental Research Funds for the Central Universities(No.HUST:2017KFYXJJ033)+1 种基金the Science Fund for Creative Research Groups of the Natural Science Foundation of Hubei(No.2018CFA004)the Major Projects of Technical Innovation of Hubei(No.2018AAA040)
文摘We have investigated the whole polarization-extinction-ratio(PER) spectrum and annealing properties of45°-tilted fiber gratings(45°-TFGs). Experimental results show the PER spectrum of 45°-TFGs is a Gaussianlike profile and covers a 540 nm bandwidth from 1260 to 1800 nm, in which the bandwidth with PER greater than 10 dB is over 250 nm. The output polarization distribution of 45°-TFGs was analyzed by employing a bulk linear polarizer, and the results show a perfect figure "8", which indicates that the 45°-TFG is a type of linear polarizer. Moreover, the annealing property of 45°-TFGs was measured up to 700°C, in which the PER of the grating started to decrease at 300°C and reached the minimum at 700°C. Based on these results, the 45°-TFGs can be used as an ultra-wide bandwidth in-fiber polarizing device.
基金supported by the National Key R&D Program of China(No.2018YFF01011800)the National Natural Science Foundation of China(No.61775070)
文摘This Letter shows the Vernier effect based on two segments of PANDA polarization maintaining fiber(PMF),whose lengths are 28 and 23 cm, respectively. The two PMFs are spliced together, and the angle between the fast axes is set to 45°. This cascaded PMF is inserted in a Sagnac loop to form an interferometer that can generate the Vernier effect. The spectrum consists of finesse fringe and envelope and realizes simultaneous measurement of strain and temperature. The envelope can provide strain and temperature sensitivities of 58.0 pm/με and -1.05 nm/℃. The finesse fringe provides sensitivities of 5.9 pm/με and -1.36 nm/℃.
基金supported by the Major Program of National Natural Science Foundation of China(No.60937002)the National Natural Science Foundation of China(No.60907037)the Fundamental Research Funds for the Central Universities(HUST:2011TS059)
文摘We propose a high sensitivity sensor based on a mode number-encoded multi-longitudinal mode fiber laser. The fiber laser incorporates a uniform fiber Bragg grating （FBG） and a fiber Fabry-Perot interferometer （FFPI） as sensitive components in the cavity. The sensor counts the number of longitudinal modes （NLM） of fiber laser, which is caused by the mismatch between the reflection band of FBG and the transmission band of FFPI resulting from the application of external perturbation to the FBG. An electrical spectrum analyzer is adopted to analyze the NLM. The strain sensor is experimentally demonstrated to have sensi- tivity of as high as 0.02 με/mode.
基金supported in part by the National Natural Science Foundation of China(Nos.61601049 and 61431003)the National 863 Program of China(No.2015AA016903)
文摘In this Letter, we experimentally demonstrate a full-duplex transmission system of IEEE 802.11ac-compliant multiple-input multiple-output （MIMO） signals over a 2-kin 7-core fiber for in-building wireless local-area net- work （WLAN） distributed antenna systems. For full-duplex 3 x 3 MIMO demonstration, the crosstalk impacts of both fiber-transmission-only and optic-wireless transmission situation are evaluated. The results indicate that the impact of crosstalk on radio-over-fiber （ROF） link performance is not significant and the quality of the cascaded multi-core fiber and wireless channel is mainly determined by the wireless part. To further improve the system capacity, polarization multiplexing （PolMux） technology is employed to achieve a full-duplex 6 × 6 MIMO over a single 7-core fiber. Although employing the PolMux method will slightly decrease the EVM and condition number performance as opposed to a non-PolMux MCF system, it is still a competitive solution in large optical connection demand scenarios that require a low cost.
基金supported by the National Natural Science Foundation of China(Nos.61331010 and 61205063)the National 863 Program of China(No.2015AA016904)the Program for New Century Excellent Talents in University(No.NCET-13-0235)
文摘With the increasing capacity demands fueled by the emerging heterogeneous and bandwidth-intensive applica- tions, such as cloud computing, 4K/8K videos, and virtual reality （VR）, the need for low-cost, power-efficient, and high-density short-reach optical interconnects operating at 100 Gb/s and beyond has drawn significant research efforts.
基金supported by the National Natural Science Foundation of China(Nos.61775070 and 61275083)the Fundamental Research Funds for the Central Universities(No.2017KFYXJJ032)
文摘In this Letter, an alternative solution is proposed and demonstrated for simultaneous measurement of axial strain and temperature. This sensor consists of two twisted points on a commercial single mode fiber introduced by flame-heated and rotation treatment. The fabrication process modifies the geometrical configuration and refractive index of the fiber. Different cladding modes are excited at the first twisted point, and part of them are coupled back to the fiber core at the second twisted point. Experimental results show distinct sensitivities of 34.9 pm/με with 49.23 pm/℃ and -36.19 pm/με with 62.99 pm/℃ for the two selected destructive interference wavelengths.
