Large numbers of basic transceiver stations,where the telecommunication room is one of the main components,comprise an important part of the telecommunication system.After earthquakes,considerable economic loss from t...Large numbers of basic transceiver stations,where the telecommunication room is one of the main components,comprise an important part of the telecommunication system.After earthquakes,considerable economic loss from telecommunication systems is often associated with seismic damage and functional loss of the telecommunication room.However,research related to this has been limited.In this study,shaking table tests were conducted for a full-scale typical telecommunication room,including a light-steel house and the necessary communication and power supply equipment.The tests not only focused on the seismic damage to all the structures but also considered the functions of the communication and power supply of the equipment.The interactions between these facilities and their effects on communication function were also investigated.Compared with the damage to structures,the interruption of the power supply due to earthquakes is a weak link.Finally,the damage indexes,together with their threshold values of different damage states for the communication and power supply equipment,were derived from the test results.The results of this research can contribute to the literature gaps regarding seismic performance studies of telecommunication rooms,and can serve as a valuable reference for future research on its seismic fragility and economic losses evaluation.展开更多
Traditional magnetically coupled resonant wireless power transfer technology uses fixed distances between coils for research,to prevent fluctuations in the receiving voltage,and lead to reduce transmission efficiency....Traditional magnetically coupled resonant wireless power transfer technology uses fixed distances between coils for research,to prevent fluctuations in the receiving voltage,and lead to reduce transmission efficiency.This paper proposes a closed-loop control wireless communication wireless power transfer system with a wearable four-coil structure to stabilize the receiving voltage fluctuation caused by changes in the displacement between the coils.Test results show that the system can provide stable receiving voltage,no matter how the distance between the transmitting coil and the receiving coil is changed.When the transmission distance is 20 mm,the power transfer efficiency of the system can reach 18.5%under the open-loop state,and the stimulus parameters such as the stimulation period and pulse width can be adjusted in real time through the personal computer terminal.展开更多
In the future fifth generation(5G) systems,non-orthogonal multiple access(NOMA) is a promising technology that can greatly enhance the network capacity compared to orthogonal multiple access(OMA) .In this paper,we pro...In the future fifth generation(5G) systems,non-orthogonal multiple access(NOMA) is a promising technology that can greatly enhance the network capacity compared to orthogonal multiple access(OMA) .In this paper,we propose a novel random access(RA) and resource allocation scheme for the coexistence of NOMA-based and OMAbased machine-to-machine(M2M) communications,which aims at improving the number of successful data packet transmissions and guaranteeing the quality of service(Qo S) (e.g.,the minimum data rate requirement) for M2 M communications.The algorithm of joint user equipment(UE) paring and power allocation is proposed for the coexisting RA(i.e.,the coexistence of NOMA-based RA and OMA-based RA) .The resource allocation for the coexisting RA is investigated,thus improving the number of successful data packet transmissions by more efficiently using the radio resources.Simulation results demonstrate that the proposed RA and resource allocation scheme outperforms the conventional RA in terms of the number of successful data packet transmissions,thus is a promising technology in future M2 M communications.展开更多
A mode of process/thread communication between QNX and WINDOWS operating systems in isomerous computers is described. It is proved in practice to be an entirely feasible mode with high efficiency and reliability. A so...A mode of process/thread communication between QNX and WINDOWS operating systems in isomerous computers is described. It is proved in practice to be an entirely feasible mode with high efficiency and reliability. A socket created by Socket API is used to communicate between two operating systems.展开更多
Communication tower(CT)and its accessory equipment(AE)such as radio frequency equipment(RFE)and antenna,are essential in providing highspeed and stable mobile network services.It is necessary to routinely monitor the ...Communication tower(CT)and its accessory equipment(AE)such as radio frequency equipment(RFE)and antenna,are essential in providing highspeed and stable mobile network services.It is necessary to routinely monitor the security and stability of CT and AE for seamless communication.There is limited research on fine segmentation of communication base station objects.This paper proposes a method for accurately segmenting the point cloud of the CT and AE from Terrestrial Laser Scanning(TLS)data.At first,the CT point cloud is accurately segmented based on region growing and Random Sample Consensus(RANSAC).Then,the point cloud of pole-shaped apart is extended to a certain distance to obtain the buffer point cloud containing AE.Normal Differential(ND)clustering is employed to obtain several groups of clusters containing planes,and calculate each plane's filling rate and size.Finally,the cluster type(such as antenna,RFE,or other)is distinguished.The experimental results demonstrate that the point-based average F1-score of CTs is 98.70%,the point-based and object-based average F1-scores of antennas are 96.09%and 97.93%,and the corresponding values for the RFE are 89.89%and 90.00%,respectively,indicating the optimal performance of the proposed method.展开更多
To overcome the drawback of a short operation range and low-resolution of a passive location system using a civil communication signal, the new idea that utilizes code division multiple access (CDMA) signal and repe...To overcome the drawback of a short operation range and low-resolution of a passive location system using a civil communication signal, the new idea that utilizes code division multiple access (CDMA) signal and repeater is disposed off. First, the CDMA passive location model and observation function are given, and the error source and error range are analyzed. Subsequently, the CDMA passive location algorithm in a repeater environment is described and simulated. The simulation result shows that the algorithm can provide the location value with high accuracy.展开更多
Several well-publicized cases of improper cleaning,disinfection or sterilization of contaminated reusable medical equipment that posed an increased risk of patientto-patient disease transmission were reported within t...Several well-publicized cases of improper cleaning,disinfection or sterilization of contaminated reusable medical equipment that posed an increased risk of patientto-patient disease transmission were reported within the past few years,resulting in the notification of approximately 20 000 patients.These medical errors,the specific infection-control standards they breached,and assessments of the risk of infection associated with each are discussed.Other topics discussed include the Food and Drug Administration’s(FDA)regulation of medical devices and infection-control products;the use of adulterated,misbranded,and investigational devices;consent decrees and associated Certificates of Medical Necessity;and informed patient consent.Focus is placed on liquid chemical sterilization,its history,and the FDA’s recent censure and discontinuation of a medical device labeled with this claim,namely,the STERIS System 1 processor.Recommendations are provided for healthcare facilities,regulatory agencies,manufacturers of reusable medical devices,and professional healthcare organizations and administrations to improve public health and prevent healthcareassociated infections.展开更多
A 40-Gb/s optical time division multiplexing (OTDM) return-to-zero (RZ) transmission experiments including a dynamic polarization mode dispersion (PMD) compensation was reported. The dynamic PMD compensator is made up...A 40-Gb/s optical time division multiplexing (OTDM) return-to-zero (RZ) transmission experiments including a dynamic polarization mode dispersion (PMD) compensation was reported. The dynamic PMD compensator is made up of two-stage four degrees of freedom (DOF). The first stage adopts polarization controller and fixed time-delayed line. The second stage is variable differential group delay (DGD) element. The PMD monitoring technique is based on degree of polarization (DOP) as error signal. A novel practical adaptive optimization algorithm was introduced in dynamic adaptive PMD compensation. The experimental results show that the performance of the PMD compensator is excellent for 40-Gb/s RZ transmission systems with the large DGD. With this compensator, a significant improvement of system performance can be achieved in the eye pattern of a received signal. The first-order compensating ability of the compensator is greater than 30 ps. The second-order compensating ability is greater than 200 ps2. The first-order optimum compensating time is within 10 ms. The second-order optimum compensating time is within 24 ms.展开更多
Objective To determine a network solution to meet the network requirements of the heavy data flow, load balance, and potential network storms from expansion of picture archiving and communication system (PACS) appli...Objective To determine a network solution to meet the network requirements of the heavy data flow, load balance, and potential network storms from expansion of picture archiving and communication system (PACS) application.Methods Intel Netstructure 480T Giga Switch was used as the main switch and connected to each building by fiber channel at 1 Giga speed to archive 100 MB/s to each port. At the same time, the in-dependence of the original network construction was physically kept. The layer 3 and 4 switchers were used as load balance to reduce the heavy load of the network, and all the cabling for PACS used the super CAT5 along with the Intel NetStructure 1520 to prepare for potential network storms.Results An advanced intranet was set up to fully meet the high standard requirement of the PACS. The foundation for upgrading the whole network system to 1 Giga application was built to achieve sharing and transmission of images, information, and patient data within the hospital. The base was established for the standardized management of the hospital.Conclusion Good planning is the first step in setting up PACS, and the equipment forms the necessary platform to run PACS and all kinds of hospital information system (HIS). The networking construction is the foundation of e-hospital.展开更多
This paper shows the current status of companies in the information and communication technology(ICT)sector in Santiago,Chile.It presents the results of interviews with 13 ICT companies,reviewing structural elements t...This paper shows the current status of companies in the information and communication technology(ICT)sector in Santiago,Chile.It presents the results of interviews with 13 ICT companies,reviewing structural elements that determine the development of the sector.For this purpose,a qualitative analysis of that interviewed group is carried out to identify their different linkages and work dynamics.This sector has a great capacity for stimulating innovative development throughout the national economy,a key element in the paradigmatic change that the so-called fourth industrial revolution imposes on us.展开更多
We present a modified method to design photonic crystal fibers (PCFs) with flattened dispersion char- acteristic. Using this modified PCF we design a broadband fiber optical parametric amplifier (FOPA), which provides...We present a modified method to design photonic crystal fibers (PCFs) with flattened dispersion char- acteristic. Using this modified PCF we design a broadband fiber optical parametric amplifier (FOPA), which provides a gain of 8 dB with 1.5-dB uniformity over a 260-nm bandwidth. Both the simulation results of total dispersion of PCF and the gain spectrum of FOPA are demonstrated.展开更多
A low cost 8×10-Gb/s transmission system over 1500 km on conventional fiber using chirped fiber Bragg grating (CFBG) as dispersion compensator is demonstrated. The bit error rate (BER) below 10^-10 at 1500 km...A low cost 8×10-Gb/s transmission system over 1500 km on conventional fiber using chirped fiber Bragg grating (CFBG) as dispersion compensator is demonstrated. The bit error rate (BER) below 10^-10 at 1500 km is obtained. The channel spacing is 0.8 nm and the optical amplifier spacing is 100 km. Only 16 erbium-doped fiber amplifiers (EDFAs) are used.展开更多
A hybrid wavelength division multiple access (WDMA)/optical code division multiplexing (OCDM) system is proposed, where the optical code is not the same as the address of every optical network unit (ONU); rather...A hybrid wavelength division multiple access (WDMA)/optical code division multiplexing (OCDM) system is proposed, where the optical code is not the same as the address of every optical network unit (ONU); rather, the code is a virtual fiber of hybrid passive optical network (PON). To our knowledge, this is the first report analyzing a single encoder/decoder with a single corresponding optical code being exploited to encode/decode multiple wavelength signals simultaneously. This system enables OCDM to become transparent to ONU so that the existing wavelength division multiplexing (WDM) PON can be upgraded. Thus, redesigning the optical line terminal and ONU can be easily accomplished, and greatly decreasing the number of encoder/decoder becomes possible. In experiment, we only employ two encoder/decoder pairs to combine two WDM-PONs in one fiber. Simulation results confirm the feasibility of the proposed system.展开更多
Er3+-doped heavy metal borosilicate glasses were prepared using conventional melting and quenching method. The emission spectra of 4I13/2 → 4I15/2 transition were observed upon excitation at 974 nm and the lifetime o...Er3+-doped heavy metal borosilicate glasses were prepared using conventional melting and quenching method. The emission spectra of 4I13/2 → 4I15/2 transition were observed upon excitation at 974 nm and the lifetime of 4I13/2 level of Er3+ was measured. Based on these data, the fluorescence properties of Er3+ are investigated on the emission and gain characteristics at the 1.5 μm bands. In particular, the effect of relative heavy metal content on fluorescence properties is discussed.展开更多
The nonlinear optical loop mirror (NOLM) is used as a saturable absorbed to reshape pulses. Experimentally, an actively mode-locked erbium-doped fiber ring laser with figure-eight structure is set up. 2 - 4 order harm...The nonlinear optical loop mirror (NOLM) is used as a saturable absorbed to reshape pulses. Experimentally, an actively mode-locked erbium-doped fiber ring laser with figure-eight structure is set up. 2 - 4 order harmonic pulse train with stable amplitude has been obtained when the RF modulation frequency is about 2.5 GHz.展开更多
We propose a 1st and 2nd order polarization mode dispersion emulator (PMDE) with one variable differential group delay (DGD) clement using birefringence crystals and four polarization controllers (PCs). Monte Ca...We propose a 1st and 2nd order polarization mode dispersion emulator (PMDE) with one variable differential group delay (DGD) clement using birefringence crystals and four polarization controllers (PCs). Monte Carlo simulations demonstrate that the output 1st and 2nd order polarization mode dispersion (PMD) generated by the PMDE consists with statistic theory. Compared with former PMDEs, this design is tunable, lower-cost, and more integrated for fabrication, which shows response time of 150μs, response frequency of 3.8 kHz, working wavelength of 1550 nm, total power consumption of less than 3 W, working range of 0 84 ps and 0 3600 ps^2 for 1st and 2nd order PMD emulation, respectively. Also, it is programmable and can be controlled by either singlechip or computer. It can be applied to study the outage probability of optical communication systems due to PMD effect and the effectiveness of PMD compensation.展开更多
An optimized two-stage-cascade double-pass structure L-band preamplifier was proposed and experimentally studied to overcome the shortcomings of low gain coefficient and high noise figure of L-band erbiumdoped fiber a...An optimized two-stage-cascade double-pass structure L-band preamplifier was proposed and experimentally studied to overcome the shortcomings of low gain coefficient and high noise figure of L-band erbiumdoped fiber amplifier (EDFA). The fiber lengthes of 6.5 and 32.5 m, pump powers of 130 and 119 mW for the first and second stages respectively are used in the experiment. When input signal power is-30 dBm, the amplifier can provide gain above 38.84 dB in a wavelength range of 34 nm (1568-1602 nm), gain ripple less than 2.04 dB (40.88-38.84 dB), and noise figures lower than 5.29 dB with the lowest value of 3.95 dB at 1590 nm. Experimental and simulation results show that this low cost and high pump efficiency amplifier is suitable for the application as an L-band preamplifier in the broadband fiber communication system.展开更多
A spectrum-sliced multi-wavelength fiber source (SS-MWFS) based on double-pass superfluorescent fiber source (SFS) with a reflection Mach-Zehnder filter (RMZF) as the reflected comb filter is demonstrated. With backwa...A spectrum-sliced multi-wavelength fiber source (SS-MWFS) based on double-pass superfluorescent fiber source (SFS) with a reflection Mach-Zehnder filter (RMZF) as the reflected comb filter is demonstrated. With backward pumped configuration, MWFS with 50 wavelength channels of extinction ratio (ER) of 16.7 dB is obtained over the almost total C-band gain region. Total output power of the MWFS is 16.2 mW which shows that a power of about 0.3 mW of per channel is achieved. The SS-MWFS with forward pumped configuration is also discussed for comparing. The backward pumped configuration can provide a larger output power while only a little smaller ER than that of the forward pumped configuration.展开更多
基金Key Project of the Key Laboratory of Earthquake Engineering and Engineering Vibration,China Earthquake Administration under Grant Nos.2020EEEVL0502 and 2019EEEVL0304。
文摘Large numbers of basic transceiver stations,where the telecommunication room is one of the main components,comprise an important part of the telecommunication system.After earthquakes,considerable economic loss from telecommunication systems is often associated with seismic damage and functional loss of the telecommunication room.However,research related to this has been limited.In this study,shaking table tests were conducted for a full-scale typical telecommunication room,including a light-steel house and the necessary communication and power supply equipment.The tests not only focused on the seismic damage to all the structures but also considered the functions of the communication and power supply of the equipment.The interactions between these facilities and their effects on communication function were also investigated.Compared with the damage to structures,the interruption of the power supply due to earthquakes is a weak link.Finally,the damage indexes,together with their threshold values of different damage states for the communication and power supply equipment,were derived from the test results.The results of this research can contribute to the literature gaps regarding seismic performance studies of telecommunication rooms,and can serve as a valuable reference for future research on its seismic fragility and economic losses evaluation.
基金supported by the National Natural Science Foundation of China(61674049,U19A2053)State Key Lab of ASIC and System(2019KF003)the Fundamental Research Funds for Central Universities(JZ2019HGTB0092)。
文摘Traditional magnetically coupled resonant wireless power transfer technology uses fixed distances between coils for research,to prevent fluctuations in the receiving voltage,and lead to reduce transmission efficiency.This paper proposes a closed-loop control wireless communication wireless power transfer system with a wearable four-coil structure to stabilize the receiving voltage fluctuation caused by changes in the displacement between the coils.Test results show that the system can provide stable receiving voltage,no matter how the distance between the transmitting coil and the receiving coil is changed.When the transmission distance is 20 mm,the power transfer efficiency of the system can reach 18.5%under the open-loop state,and the stimulus parameters such as the stimulation period and pulse width can be adjusted in real time through the personal computer terminal.
基金supported by the National Natural Science Foundation of China(61501056)National Science and Technology Major Project of China(No.2016ZX03001012)the Research Fund of ZTE Corporation
文摘In the future fifth generation(5G) systems,non-orthogonal multiple access(NOMA) is a promising technology that can greatly enhance the network capacity compared to orthogonal multiple access(OMA) .In this paper,we propose a novel random access(RA) and resource allocation scheme for the coexistence of NOMA-based and OMAbased machine-to-machine(M2M) communications,which aims at improving the number of successful data packet transmissions and guaranteeing the quality of service(Qo S) (e.g.,the minimum data rate requirement) for M2 M communications.The algorithm of joint user equipment(UE) paring and power allocation is proposed for the coexisting RA(i.e.,the coexistence of NOMA-based RA and OMA-based RA) .The resource allocation for the coexisting RA is investigated,thus improving the number of successful data packet transmissions by more efficiently using the radio resources.Simulation results demonstrate that the proposed RA and resource allocation scheme outperforms the conventional RA in terms of the number of successful data packet transmissions,thus is a promising technology in future M2 M communications.
基金The project supported by the National Meg-science Engineering project of the Chinese Government
文摘A mode of process/thread communication between QNX and WINDOWS operating systems in isomerous computers is described. It is proved in practice to be an entirely feasible mode with high efficiency and reliability. A socket created by Socket API is used to communicate between two operating systems.
基金funded by Guangxi Natural Science Fund for Innovation Research Team[grant number 2019GXNSFGA245001]High-Level Talent Aggregation Project in Hunan Province,China-Innovation Team[grant number 2019RS1060].
文摘Communication tower(CT)and its accessory equipment(AE)such as radio frequency equipment(RFE)and antenna,are essential in providing highspeed and stable mobile network services.It is necessary to routinely monitor the security and stability of CT and AE for seamless communication.There is limited research on fine segmentation of communication base station objects.This paper proposes a method for accurately segmenting the point cloud of the CT and AE from Terrestrial Laser Scanning(TLS)data.At first,the CT point cloud is accurately segmented based on region growing and Random Sample Consensus(RANSAC).Then,the point cloud of pole-shaped apart is extended to a certain distance to obtain the buffer point cloud containing AE.Normal Differential(ND)clustering is employed to obtain several groups of clusters containing planes,and calculate each plane's filling rate and size.Finally,the cluster type(such as antenna,RFE,or other)is distinguished.The experimental results demonstrate that the point-based average F1-score of CTs is 98.70%,the point-based and object-based average F1-scores of antennas are 96.09%and 97.93%,and the corresponding values for the RFE are 89.89%and 90.00%,respectively,indicating the optimal performance of the proposed method.
基金the Key Project of Ministry of Education (207097)Education Natural Science Foundation Project of CQCSTC (2006BB2376)
文摘To overcome the drawback of a short operation range and low-resolution of a passive location system using a civil communication signal, the new idea that utilizes code division multiple access (CDMA) signal and repeater is disposed off. First, the CDMA passive location model and observation function are given, and the error source and error range are analyzed. Subsequently, the CDMA passive location algorithm in a repeater environment is described and simulated. The simulation result shows that the algorithm can provide the location value with high accuracy.
文摘Several well-publicized cases of improper cleaning,disinfection or sterilization of contaminated reusable medical equipment that posed an increased risk of patientto-patient disease transmission were reported within the past few years,resulting in the notification of approximately 20 000 patients.These medical errors,the specific infection-control standards they breached,and assessments of the risk of infection associated with each are discussed.Other topics discussed include the Food and Drug Administration’s(FDA)regulation of medical devices and infection-control products;the use of adulterated,misbranded,and investigational devices;consent decrees and associated Certificates of Medical Necessity;and informed patient consent.Focus is placed on liquid chemical sterilization,its history,and the FDA’s recent censure and discontinuation of a medical device labeled with this claim,namely,the STERIS System 1 processor.Recommendations are provided for healthcare facilities,regulatory agencies,manufacturers of reusable medical devices,and professional healthcare organizations and administrations to improve public health and prevent healthcareassociated infections.
基金This work was supported by the National Natural Science Foundation of China (No. 60177027 and 60377015) and the National "863" Project of China (No. 2001AA122042).
文摘A 40-Gb/s optical time division multiplexing (OTDM) return-to-zero (RZ) transmission experiments including a dynamic polarization mode dispersion (PMD) compensation was reported. The dynamic PMD compensator is made up of two-stage four degrees of freedom (DOF). The first stage adopts polarization controller and fixed time-delayed line. The second stage is variable differential group delay (DGD) element. The PMD monitoring technique is based on degree of polarization (DOP) as error signal. A novel practical adaptive optimization algorithm was introduced in dynamic adaptive PMD compensation. The experimental results show that the performance of the PMD compensator is excellent for 40-Gb/s RZ transmission systems with the large DGD. With this compensator, a significant improvement of system performance can be achieved in the eye pattern of a received signal. The first-order compensating ability of the compensator is greater than 30 ps. The second-order compensating ability is greater than 200 ps2. The first-order optimum compensating time is within 10 ms. The second-order optimum compensating time is within 24 ms.
文摘Objective To determine a network solution to meet the network requirements of the heavy data flow, load balance, and potential network storms from expansion of picture archiving and communication system (PACS) application.Methods Intel Netstructure 480T Giga Switch was used as the main switch and connected to each building by fiber channel at 1 Giga speed to archive 100 MB/s to each port. At the same time, the in-dependence of the original network construction was physically kept. The layer 3 and 4 switchers were used as load balance to reduce the heavy load of the network, and all the cabling for PACS used the super CAT5 along with the Intel NetStructure 1520 to prepare for potential network storms.Results An advanced intranet was set up to fully meet the high standard requirement of the PACS. The foundation for upgrading the whole network system to 1 Giga application was built to achieve sharing and transmission of images, information, and patient data within the hospital. The base was established for the standardized management of the hospital.Conclusion Good planning is the first step in setting up PACS, and the equipment forms the necessary platform to run PACS and all kinds of hospital information system (HIS). The networking construction is the foundation of e-hospital.
文摘This paper shows the current status of companies in the information and communication technology(ICT)sector in Santiago,Chile.It presents the results of interviews with 13 ICT companies,reviewing structural elements that determine the development of the sector.For this purpose,a qualitative analysis of that interviewed group is carried out to identify their different linkages and work dynamics.This sector has a great capacity for stimulating innovative development throughout the national economy,a key element in the paradigmatic change that the so-called fourth industrial revolution imposes on us.
基金This work was supported by the National Natural Sci- ence Foundation of China under Grant No. 60377023.
文摘We present a modified method to design photonic crystal fibers (PCFs) with flattened dispersion char- acteristic. Using this modified PCF we design a broadband fiber optical parametric amplifier (FOPA), which provides a gain of 8 dB with 1.5-dB uniformity over a 260-nm bandwidth. Both the simulation results of total dispersion of PCF and the gain spectrum of FOPA are demonstrated.
基金This work was supported by the "863" High-Technology Research and Development Program ofChina under Grant No. 2001AA120201
文摘A low cost 8×10-Gb/s transmission system over 1500 km on conventional fiber using chirped fiber Bragg grating (CFBG) as dispersion compensator is demonstrated. The bit error rate (BER) below 10^-10 at 1500 km is obtained. The channel spacing is 0.8 nm and the optical amplifier spacing is 100 km. Only 16 erbium-doped fiber amplifiers (EDFAs) are used.
基金supported by the National Natural Science Fundation of China(Nos.60972032 and 60632010)the National"863"Project of China(Nos. 2006AA01Z251 and 2007AA01Z271)
文摘A hybrid wavelength division multiple access (WDMA)/optical code division multiplexing (OCDM) system is proposed, where the optical code is not the same as the address of every optical network unit (ONU); rather, the code is a virtual fiber of hybrid passive optical network (PON). To our knowledge, this is the first report analyzing a single encoder/decoder with a single corresponding optical code being exploited to encode/decode multiple wavelength signals simultaneously. This system enables OCDM to become transparent to ONU so that the existing wavelength division multiplexing (WDM) PON can be upgraded. Thus, redesigning the optical line terminal and ONU can be easily accomplished, and greatly decreasing the number of encoder/decoder becomes possible. In experiment, we only employ two encoder/decoder pairs to combine two WDM-PONs in one fiber. Simulation results confirm the feasibility of the proposed system.
基金This work was supported by Shanghai Science and Technology Foundation (022261046) and the National Natural Science Foundation (60207006).
文摘Er3+-doped heavy metal borosilicate glasses were prepared using conventional melting and quenching method. The emission spectra of 4I13/2 → 4I15/2 transition were observed upon excitation at 974 nm and the lifetime of 4I13/2 level of Er3+ was measured. Based on these data, the fluorescence properties of Er3+ are investigated on the emission and gain characteristics at the 1.5 μm bands. In particular, the effect of relative heavy metal content on fluorescence properties is discussed.
基金This work was supported by the Doctoral Programme Foundation of the Institution of Higher Education of China (No. 1999005615) and the National Natural Science Foundation of China (No. 69877012).
文摘The nonlinear optical loop mirror (NOLM) is used as a saturable absorbed to reshape pulses. Experimentally, an actively mode-locked erbium-doped fiber ring laser with figure-eight structure is set up. 2 - 4 order harmonic pulse train with stable amplitude has been obtained when the RF modulation frequency is about 2.5 GHz.
基金This work was in part supported by the Trans-CenturyTraining Programme Foundation for the Talents by theMinistry of Education of China
文摘We propose a 1st and 2nd order polarization mode dispersion emulator (PMDE) with one variable differential group delay (DGD) clement using birefringence crystals and four polarization controllers (PCs). Monte Carlo simulations demonstrate that the output 1st and 2nd order polarization mode dispersion (PMD) generated by the PMDE consists with statistic theory. Compared with former PMDEs, this design is tunable, lower-cost, and more integrated for fabrication, which shows response time of 150μs, response frequency of 3.8 kHz, working wavelength of 1550 nm, total power consumption of less than 3 W, working range of 0 84 ps and 0 3600 ps^2 for 1st and 2nd order PMD emulation, respectively. Also, it is programmable and can be controlled by either singlechip or computer. It can be applied to study the outage probability of optical communication systems due to PMD effect and the effectiveness of PMD compensation.
基金This work was supported by the Tianjin Science and Technology Development Foundation under Grant No.033800411.D. Jia's e-mail address is jiadf@163.com.
文摘An optimized two-stage-cascade double-pass structure L-band preamplifier was proposed and experimentally studied to overcome the shortcomings of low gain coefficient and high noise figure of L-band erbiumdoped fiber amplifier (EDFA). The fiber lengthes of 6.5 and 32.5 m, pump powers of 130 and 119 mW for the first and second stages respectively are used in the experiment. When input signal power is-30 dBm, the amplifier can provide gain above 38.84 dB in a wavelength range of 34 nm (1568-1602 nm), gain ripple less than 2.04 dB (40.88-38.84 dB), and noise figures lower than 5.29 dB with the lowest value of 3.95 dB at 1590 nm. Experimental and simulation results show that this low cost and high pump efficiency amplifier is suitable for the application as an L-band preamplifier in the broadband fiber communication system.
基金This work was supported by the Fujian Provincial Key Laboratory of Photonic Technology (No.FP0408) and the Natural Science Foundation of Fujian Province (No. A0440009).
文摘A spectrum-sliced multi-wavelength fiber source (SS-MWFS) based on double-pass superfluorescent fiber source (SFS) with a reflection Mach-Zehnder filter (RMZF) as the reflected comb filter is demonstrated. With backward pumped configuration, MWFS with 50 wavelength channels of extinction ratio (ER) of 16.7 dB is obtained over the almost total C-band gain region. Total output power of the MWFS is 16.2 mW which shows that a power of about 0.3 mW of per channel is achieved. The SS-MWFS with forward pumped configuration is also discussed for comparing. The backward pumped configuration can provide a larger output power while only a little smaller ER than that of the forward pumped configuration.