Rehabilitation of existing structures with fiber reinforced plastic(FRP)has been growing in popularity because they offer superior performance in terms of resistance to corrosion and high specific stiffness.The strain...Rehabilitation of existing structures with fiber reinforced plastic(FRP)has been growing in popularity because they offer superior performance in terms of resistance to corrosion and high specific stiffness.The strain coordination results of 34 reinforced concrete beams(four groups)strengthened with different methods were presented including external-bonded or near-surface mounted glass or carbon FRP or helical rib bar in order to study the strain coordination of the strengthening materials and steel rebar of RC beam.Because there is relative slipping between concrete and strengthening materials(SM),the strain of SM and steel rebar of RC beam satisfies the double linear strain distribution assumption,that is,the strain of longitudinal fiber parallel to the neutral axis of plated beam within the scope of effective height(h0)of the cross section is in direct proportion to the distance from the fiber to the neutral axis.The strain of SM and steel rebar satisfies the equation εGCH=βεsteel,where the value of β is equal to 1.1-1.3 according to the test results.展开更多
Compared with traditional optical fiber lasers,double-clad photonic crystal fiber (PCF) lasers have larger surfacearea-to-volume ratios.With an increase of output power,thermal effects may severely restrict output pow...Compared with traditional optical fiber lasers,double-clad photonic crystal fiber (PCF) lasers have larger surfacearea-to-volume ratios.With an increase of output power,thermal effects may severely restrict output power and deteriorate beam quality of fiber lasers.We utilize the heat-conduction equations to estimate the maximum output power of a double-clad PCF laser under natural-convection,air-cooling,and water-cooling conditions in terms of a certain surface-volume heat ratio of the PCF.The thermal effects hence define an upper power limit of double-clad PCF lasers when scaling output power.展开更多
Amplified spontaneous emission (ASE) in diode laser pumped double-clad fiber power amplifiers is studied experimentally, The dependences of ASE on fiber length and cross section of active core are discussed and the ...Amplified spontaneous emission (ASE) in diode laser pumped double-clad fiber power amplifiers is studied experimentally, The dependences of ASE on fiber length and cross section of active core are discussed and the variations of ASE power as the function of pumping and signal power are investigated. There are indications that long fibers with large mode area need stronger input signals to suppress ASE. It is shown that a 150 mW input signal can suppress the ASE by 40 dB in a 4 m large mode area fiber, while to efficiently suppress the ASE in a 10 m fiber, stronger input signal is needed. 12.5 W and 16.1 W single frequency CW output power are obtained from 4 m fiber and 10 m fiber respectively. No stimulated Brillouin scattering (SBS) was observed展开更多
Presented is a theoretical study of double-clad Er-doped fiber power amplifier(EDFA). Two kinds of double clad fibers(DCF) with rectangular and "flower" inner clad shapes are studied, and these fibers have d...Presented is a theoretical study of double-clad Er-doped fiber power amplifier(EDFA). Two kinds of double clad fibers(DCF) with rectangular and "flower" inner clad shapes are studied, and these fibers have different coupling constants and propagation losses. We calculate the effective pump power absorption ratio along the fiber with different coupling constants from the first cladding to the doped core and with different propagation losses for the power in the inner cladding. Then the gains of the double clad Er-doped fiber amplifiers versus fiber lengths are calculated using the EDFA model based on propagation and rate equations of a homogeneous, two-level medium.展开更多
Abstract: A new pyrometer, which can solve the affection of emissivity change in temperature measuring, has been developed by double Y - type optical fibers. The mathematical model of the new pyrometer is presented an...Abstract: A new pyrometer, which can solve the affection of emissivity change in temperature measuring, has been developed by double Y - type optical fibers. The mathematical model of the new pyrometer is presented and the errors of the new pyrometer are analyzed.展开更多
Absorption efficiency of graded-index double-clad fiber lasers or amplifiers is analyzed. As ray optics method is no longer valid for graded-index case, the mode analysis method is used. Calculated results show that a...Absorption efficiency of graded-index double-clad fiber lasers or amplifiers is analyzed. As ray optics method is no longer valid for graded-index case, the mode analysis method is used. Calculated results show that absorption efficiency for a graded-index is higher than that for a step-index in symmetric case. In offset core case, the graded-index can achieve the same absorption efficiency with much smaller offset distance. Absorption efficiencies for different graded-index profiles of the inner cladding are compared.展开更多
Multiple-beam fringes of equal chromatic order interferometry is a powerful technique to extract optical properties over a continuous range of spectrum. In this paper we develop a theory for the spectral shape of the ...Multiple-beam fringes of equal chromatic order interferometry is a powerful technique to extract optical properties over a continuous range of spectrum. In this paper we develop a theory for the spectral shape of the fringes of equal chromatic order (FECO) that are formed across a double-clad fiber. The modified single term Sellmeier dispersion formula is used to construct the refractive index dispersion curves for the liquid, claddings, and core. Expressions for the paraxial optical path length for several rays passing through the fiber and the liquid are developed. The condition of bright fringe is applied to get an analytical expression for the spectral shape of the FECO across a double-clad fiber with an elliptical/circular inner cladding. A potential application of this theory is to determine the dispersion of Kerr constant of the claddings and the core of the fiber. To illustrate the theory and its application, simulation examples are provided and discussed.展开更多
提出并模拟证明了基于两个电光相位调制器实现抑光载波双边带(Radio on Fiber,RoF)双工传输系统设计方案.通过改变电光相位调制器的最大相偏量,实现了抑光载波双边带信号传输——使通信带宽加倍,而且很好地控制上下行传输信号的误码率....提出并模拟证明了基于两个电光相位调制器实现抑光载波双边带(Radio on Fiber,RoF)双工传输系统设计方案.通过改变电光相位调制器的最大相偏量,实现了抑光载波双边带信号传输——使通信带宽加倍,而且很好地控制上下行传输信号的误码率.仿真模拟结果表明,发射功率为3dBm的光信号在无放大、色散系数为20ps/(nm.km)、衰减系数为0.25dB/km的SMF-28单模光纤中传输时,其超高频RF调制信号的频率可达24GHz,数据码元传输速率可达2.5Gbit/s,传输距离40km以上.展开更多
A double-exposure fabrication method without any intensity shadow mask to fabricate arbitrarily apodized fiber Bragg gratings( FBGs) with narrow bandwidth is demonstrated by controlling the total ultra violet (UV)...A double-exposure fabrication method without any intensity shadow mask to fabricate arbitrarily apodized fiber Bragg gratings( FBGs) with narrow bandwidth is demonstrated by controlling the total ultra violet (UV) irradiation along the grating by varying the speed of a translation stage. The UV source used is a stable continuous intracavity frequency-doubled argonion laser. The parameters (such as length, apodization profile, average index change)of FBGs can be easily changed with this method. The total UV irradiation is kept constant in the doubleexposure process because of the precise control of the exposure time, which ensures that the apodized FBG's bandwidth can be extremely narrow. The full width at half maximum (FWHM) bandwidth of the 2-cm-long apodized FBG fabricated by this method is 0. 15 nm with a maximum reflectivity of more than 95%.展开更多
提出并模拟证明了基于电光相位调制(PM)和布拉格光纤光栅(FBG)实现受抑光载波的双边带(DSBOCS,Double-Sideband with Optical Carrier Suppression)的双向Radio over Fiber(RoF)传输系统网络设计方案.激光光源置于中心站,载有信息的光...提出并模拟证明了基于电光相位调制(PM)和布拉格光纤光栅(FBG)实现受抑光载波的双边带(DSBOCS,Double-Sideband with Optical Carrier Suppression)的双向Radio over Fiber(RoF)传输系统网络设计方案.激光光源置于中心站,载有信息的光信号通过光纤到达基站后经FBG分成两路,其中一路是被接收的下行信号,另一路作为上行信号调制后返回中心站.通过FBG,其下行信号不但实现了受抑光载波的双边带———使通信带宽加倍,上行信号作为光源通过电光强度调制,有效地实现信息的上载.仿真结果表明,光源发射功率为3 dBm,无光放大,在色散系数为20 ps/(nm.km),衰减系数为0.25 dB/km的单模光纤中传输,超高频RF信号的频率可达24 GHz,系统码元传输速率可达2.5 Gbit/s、传输距离50 km以上.展开更多
Incorporation of metallic fibers into the adhesive layer can significantly improve the mechanical behavior of the adhesive joint. This paper aims to assess the fracture behavior of an epoxy adhesive reinforced by long...Incorporation of metallic fibers into the adhesive layer can significantly improve the mechanical behavior of the adhesive joint. This paper aims to assess the fracture behavior of an epoxy adhesive reinforced by longitudinal and lateral metallic fibers. Double cantilever beam(DCB) specimens were used to obtain the fracture energy of both non-reinforced and reinforced adhesives under mode I loading condition. In addition to the fiber orientation, the distance between the metal fibers was considered as the second key parameter in the experiments. It was concluded that although incorporation of metallic fibers in the adhesive layer improves the fracture behavior of neat adhesive, however, higher improvements were observed for the adhesive reinforced with longitudinal fibers. Furthermore, reducing the fiber distances resulted in higher values of fracture energy.展开更多
The effects of the variations in fiber length,fiber mirror reflectance on efficiency and output power are experimentally investigated for erbium-doped double pass backward superfluorescent fiber sources (SFSs).The inf...The effects of the variations in fiber length,fiber mirror reflectance on efficiency and output power are experimentally investigated for erbium-doped double pass backward superfluorescent fiber sources (SFSs).The influence of fiber length on mean wavelength stability (MWS) has also been demonstrated.By incorporating a short section of un-pumped erbium-doped fiber (EDF) at the output port,the pump power dependent on MWS becomes independent of pumped EDF length.This is a novel phenomenon that hasn’t been reported up to now,and should be helpful to SFS fabrication and theory analysis.By using a fiber Michelson interferometer as spectrum slicing component,a multi-wavelength fiber source (MWFS) with ~20 channels (from 1 542 nm to 1 559 nm) is got.The MWFS has a channel spacing of ~0.8 nm which satisfies ITU-standard.The intensity fluctuation among channels is less than 0.5 dB,and the extinction ratio of all channels is above 14 dB.This kind of MWFS should be useful to wavelength division multiplexing systems.展开更多
A new "conceptual" design named "double pull" specimen was proposed in order to measure the bond-slip(δ-τ) relationship of fiber reinforced polymer(FRP)-to-concrete interface more accurately.A fi...A new "conceptual" design named "double pull" specimen was proposed in order to measure the bond-slip(δ-τ) relationship of fiber reinforced polymer(FRP)-to-concrete interface more accurately.A finite element analysis(FEA) was performed for preliminarily evaluating the suitability of the proposed conceptual double pull specimen.Through the FEA,it was indicated that the FRP-to-concrete interface of the proposed conceptual specimen might subject to a much higher load level than that of the most commonly used simple shear specimen,showing a great potential for measuring δ-τ relationship more accurately.In the light of the conceptual specimen,a kind of "practical" double pull specimen was developed and proved to be more suitable for measuring δ-τ relationship through an exploratory experimental study with 20 specimens.Consequently,an experimental program with 10 double pull specimens was performed for measuring the ultimate slip δu which was difficult to capture by using the existing specimens.It is shown that the range of δu is 0.31-0.52 mm based on the test results.The suggestion for improving the measure method is also put forward.展开更多
The system principle and configuration of the double differential pressure method for measuring oil tank level are presented. The fundamental method and circuit of fiber optic transmission are analyzed .The accuracy a...The system principle and configuration of the double differential pressure method for measuring oil tank level are presented. The fundamental method and circuit of fiber optic transmission are analyzed .The accuracy and security of level measurement in the oil tanks have been greatly improved.展开更多
The double Rayleigh backscatter (DRB) effect in long distance CATV systems using fiber Raman amplifiers (FRAs) is investigated theoretically in the paper. As a comparison, performance of a system with erbium doped...The double Rayleigh backscatter (DRB) effect in long distance CATV systems using fiber Raman amplifiers (FRAs) is investigated theoretically in the paper. As a comparison, performance of a system with erbium doped fiber amplifier (EDFA) is also evaluated. According to the simulation results, it is found that, in case of FRA, the increase of carrier-to-noise ratio (CNR) due to the DRB effect will not impair the performance more than that using EDFA.展开更多
This paper presents an investigation of specific optical fiber core mode leakage behavior that occurs in high-power double-clad fiber lasers as a result of thermally-induced refractive index variations. A model of the...This paper presents an investigation of specific optical fiber core mode leakage behavior that occurs in high-power double-clad fiber lasers as a result of thermally-induced refractive index variations. A model of the power transfer between the core modes and the cladding modes during thermally-induced refractive index variations is established based on the mode coupling theory. The results of numerical simulations based on actual laser parameters are presented. Experimental measurements were also carried out, the results showed good agreement with the corresponding simulation results.展开更多
The longitude tensile properties of 3-Dimension-4-directional(3D-4d) braided C/Si C composites(CMCs) were investigated with the help of a double scale model. This model involves micro-scale and unit-cell scale. In...The longitude tensile properties of 3-Dimension-4-directional(3D-4d) braided C/Si C composites(CMCs) were investigated with the help of a double scale model. This model involves micro-scale and unit-cell scale. In micro-scale, the tensile properties of fiber tows which involves matrix cracking, interfacial debonding, and fiber failure are studied. The unit-cell scale model can reflect the braided structure and simulate the tensile properties of 3D-4d CMCs by introducing the tensile properties of fiber tows into it. Quasi-static tensile tests of 3D-4d braided CMCs were performed on a PWS-100 test system. The predicted tensile stressstrain curve by the double scale model is in good agreement with that of the experimental results.展开更多
The use of a phase mask with 536 nm uniform pitch allowed the fabrication of a fiber Bragg grating for use at a Bragg wavelength of 785 nm. Reflection and transmission features at 1552 nm, twice the Bragg wavelength, ...The use of a phase mask with 536 nm uniform pitch allowed the fabrication of a fiber Bragg grating for use at a Bragg wavelength of 785 nm. Reflection and transmission features at 1552 nm, twice the Bragg wavelength, associated with the phase mask periodicity were observed. However, when phase mask orders other than +1 were absent during fabrication the features at 1552 nm were not evident.展开更多
基金Project(11B033)supported by the Foundation for Excellent Young Scholars of Hunan Scientific Committee,ChinaProject(116001)supported by the Consultative Program of the Chinese Academy of Engineering+1 种基金Project(11JJ6040)supported by the National Natural Science Foundation of Hunan Province,ChinaProject(2010GK3198)supported by the Science and Research Program of Hunan Province,China
文摘Rehabilitation of existing structures with fiber reinforced plastic(FRP)has been growing in popularity because they offer superior performance in terms of resistance to corrosion and high specific stiffness.The strain coordination results of 34 reinforced concrete beams(four groups)strengthened with different methods were presented including external-bonded or near-surface mounted glass or carbon FRP or helical rib bar in order to study the strain coordination of the strengthening materials and steel rebar of RC beam.Because there is relative slipping between concrete and strengthening materials(SM),the strain of SM and steel rebar of RC beam satisfies the double linear strain distribution assumption,that is,the strain of longitudinal fiber parallel to the neutral axis of plated beam within the scope of effective height(h0)of the cross section is in direct proportion to the distance from the fiber to the neutral axis.The strain of SM and steel rebar satisfies the equation εGCH=βεsteel,where the value of β is equal to 1.1-1.3 according to the test results.
基金Supported partially by the Hebei Scientific Research Project(No 2010164).
文摘Compared with traditional optical fiber lasers,double-clad photonic crystal fiber (PCF) lasers have larger surfacearea-to-volume ratios.With an increase of output power,thermal effects may severely restrict output power and deteriorate beam quality of fiber lasers.We utilize the heat-conduction equations to estimate the maximum output power of a double-clad PCF laser under natural-convection,air-cooling,and water-cooling conditions in terms of a certain surface-volume heat ratio of the PCF.The thermal effects hence define an upper power limit of double-clad PCF lasers when scaling output power.
基金the Ministerial Level Advanced Research Foundation (41302010107)
文摘Amplified spontaneous emission (ASE) in diode laser pumped double-clad fiber power amplifiers is studied experimentally, The dependences of ASE on fiber length and cross section of active core are discussed and the variations of ASE power as the function of pumping and signal power are investigated. There are indications that long fibers with large mode area need stronger input signals to suppress ASE. It is shown that a 150 mW input signal can suppress the ASE by 40 dB in a 4 m large mode area fiber, while to efficiently suppress the ASE in a 10 m fiber, stronger input signal is needed. 12.5 W and 16.1 W single frequency CW output power are obtained from 4 m fiber and 10 m fiber respectively. No stimulated Brillouin scattering (SBS) was observed
基金Foundation of Beijing Jiaotong University(2005RC034)
文摘Presented is a theoretical study of double-clad Er-doped fiber power amplifier(EDFA). Two kinds of double clad fibers(DCF) with rectangular and "flower" inner clad shapes are studied, and these fibers have different coupling constants and propagation losses. We calculate the effective pump power absorption ratio along the fiber with different coupling constants from the first cladding to the doped core and with different propagation losses for the power in the inner cladding. Then the gains of the double clad Er-doped fiber amplifiers versus fiber lengths are calculated using the EDFA model based on propagation and rate equations of a homogeneous, two-level medium.
文摘Abstract: A new pyrometer, which can solve the affection of emissivity change in temperature measuring, has been developed by double Y - type optical fibers. The mathematical model of the new pyrometer is presented and the errors of the new pyrometer are analyzed.
文摘Absorption efficiency of graded-index double-clad fiber lasers or amplifiers is analyzed. As ray optics method is no longer valid for graded-index case, the mode analysis method is used. Calculated results show that absorption efficiency for a graded-index is higher than that for a step-index in symmetric case. In offset core case, the graded-index can achieve the same absorption efficiency with much smaller offset distance. Absorption efficiencies for different graded-index profiles of the inner cladding are compared.
文摘Multiple-beam fringes of equal chromatic order interferometry is a powerful technique to extract optical properties over a continuous range of spectrum. In this paper we develop a theory for the spectral shape of the fringes of equal chromatic order (FECO) that are formed across a double-clad fiber. The modified single term Sellmeier dispersion formula is used to construct the refractive index dispersion curves for the liquid, claddings, and core. Expressions for the paraxial optical path length for several rays passing through the fiber and the liquid are developed. The condition of bright fringe is applied to get an analytical expression for the spectral shape of the FECO across a double-clad fiber with an elliptical/circular inner cladding. A potential application of this theory is to determine the dispersion of Kerr constant of the claddings and the core of the fiber. To illustrate the theory and its application, simulation examples are provided and discussed.
文摘提出并模拟证明了基于两个电光相位调制器实现抑光载波双边带(Radio on Fiber,RoF)双工传输系统设计方案.通过改变电光相位调制器的最大相偏量,实现了抑光载波双边带信号传输——使通信带宽加倍,而且很好地控制上下行传输信号的误码率.仿真模拟结果表明,发射功率为3dBm的光信号在无放大、色散系数为20ps/(nm.km)、衰减系数为0.25dB/km的SMF-28单模光纤中传输时,其超高频RF调制信号的频率可达24GHz,数据码元传输速率可达2.5Gbit/s,传输距离40km以上.
基金The Natural Science Foundation of Jiangsu Province(No.BK2004207)
文摘A double-exposure fabrication method without any intensity shadow mask to fabricate arbitrarily apodized fiber Bragg gratings( FBGs) with narrow bandwidth is demonstrated by controlling the total ultra violet (UV) irradiation along the grating by varying the speed of a translation stage. The UV source used is a stable continuous intracavity frequency-doubled argonion laser. The parameters (such as length, apodization profile, average index change)of FBGs can be easily changed with this method. The total UV irradiation is kept constant in the doubleexposure process because of the precise control of the exposure time, which ensures that the apodized FBG's bandwidth can be extremely narrow. The full width at half maximum (FWHM) bandwidth of the 2-cm-long apodized FBG fabricated by this method is 0. 15 nm with a maximum reflectivity of more than 95%.
文摘Incorporation of metallic fibers into the adhesive layer can significantly improve the mechanical behavior of the adhesive joint. This paper aims to assess the fracture behavior of an epoxy adhesive reinforced by longitudinal and lateral metallic fibers. Double cantilever beam(DCB) specimens were used to obtain the fracture energy of both non-reinforced and reinforced adhesives under mode I loading condition. In addition to the fiber orientation, the distance between the metal fibers was considered as the second key parameter in the experiments. It was concluded that although incorporation of metallic fibers in the adhesive layer improves the fracture behavior of neat adhesive, however, higher improvements were observed for the adhesive reinforced with longitudinal fibers. Furthermore, reducing the fiber distances resulted in higher values of fracture energy.
文摘The effects of the variations in fiber length,fiber mirror reflectance on efficiency and output power are experimentally investigated for erbium-doped double pass backward superfluorescent fiber sources (SFSs).The influence of fiber length on mean wavelength stability (MWS) has also been demonstrated.By incorporating a short section of un-pumped erbium-doped fiber (EDF) at the output port,the pump power dependent on MWS becomes independent of pumped EDF length.This is a novel phenomenon that hasn’t been reported up to now,and should be helpful to SFS fabrication and theory analysis.By using a fiber Michelson interferometer as spectrum slicing component,a multi-wavelength fiber source (MWFS) with ~20 channels (from 1 542 nm to 1 559 nm) is got.The MWFS has a channel spacing of ~0.8 nm which satisfies ITU-standard.The intensity fluctuation among channels is less than 0.5 dB,and the extinction ratio of all channels is above 14 dB.This kind of MWFS should be useful to wavelength division multiplexing systems.
基金Project(2006BAJ03A07) supported by the National Key Technologies R & D Program of ChinaProject(5008283) supported by the Natural Science Foundation of Guangdong Province, China
文摘A new "conceptual" design named "double pull" specimen was proposed in order to measure the bond-slip(δ-τ) relationship of fiber reinforced polymer(FRP)-to-concrete interface more accurately.A finite element analysis(FEA) was performed for preliminarily evaluating the suitability of the proposed conceptual double pull specimen.Through the FEA,it was indicated that the FRP-to-concrete interface of the proposed conceptual specimen might subject to a much higher load level than that of the most commonly used simple shear specimen,showing a great potential for measuring δ-τ relationship more accurately.In the light of the conceptual specimen,a kind of "practical" double pull specimen was developed and proved to be more suitable for measuring δ-τ relationship through an exploratory experimental study with 20 specimens.Consequently,an experimental program with 10 double pull specimens was performed for measuring the ultimate slip δu which was difficult to capture by using the existing specimens.It is shown that the range of δu is 0.31-0.52 mm based on the test results.The suggestion for improving the measure method is also put forward.
文摘The system principle and configuration of the double differential pressure method for measuring oil tank level are presented. The fundamental method and circuit of fiber optic transmission are analyzed .The accuracy and security of level measurement in the oil tanks have been greatly improved.
基金Project supported by the National Natural Science Foundation of China (Grant No.61077018)the Shanghai Leading Academic Discipline Project (Grant Nos.S30108, SKLFSO200901)
文摘The double Rayleigh backscatter (DRB) effect in long distance CATV systems using fiber Raman amplifiers (FRAs) is investigated theoretically in the paper. As a comparison, performance of a system with erbium doped fiber amplifier (EDFA) is also evaluated. According to the simulation results, it is found that, in case of FRA, the increase of carrier-to-noise ratio (CNR) due to the DRB effect will not impair the performance more than that using EDFA.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61307057 and 61675114)
文摘This paper presents an investigation of specific optical fiber core mode leakage behavior that occurs in high-power double-clad fiber lasers as a result of thermally-induced refractive index variations. A model of the power transfer between the core modes and the cladding modes during thermally-induced refractive index variations is established based on the mode coupling theory. The results of numerical simulations based on actual laser parameters are presented. Experimental measurements were also carried out, the results showed good agreement with the corresponding simulation results.
基金Funded by the National Basic Research Program of Chinathe National Natural Science Foundation of China(51675266)+3 种基金the Aeronautical Science Foundation of China(2014ZB52024)the Fundamental Research Funds for the Central Universities(NJ20160038)the Jiangsu Innovation Program for Graduate Education(CXLX13_165)the Fundamental Research Funds for the Central Universities
文摘The longitude tensile properties of 3-Dimension-4-directional(3D-4d) braided C/Si C composites(CMCs) were investigated with the help of a double scale model. This model involves micro-scale and unit-cell scale. In micro-scale, the tensile properties of fiber tows which involves matrix cracking, interfacial debonding, and fiber failure are studied. The unit-cell scale model can reflect the braided structure and simulate the tensile properties of 3D-4d CMCs by introducing the tensile properties of fiber tows into it. Quasi-static tensile tests of 3D-4d braided CMCs were performed on a PWS-100 test system. The predicted tensile stressstrain curve by the double scale model is in good agreement with that of the experimental results.
基金supported by the Australian Research Council under Grant No. DP0773999.
文摘The use of a phase mask with 536 nm uniform pitch allowed the fabrication of a fiber Bragg grating for use at a Bragg wavelength of 785 nm. Reflection and transmission features at 1552 nm, twice the Bragg wavelength, associated with the phase mask periodicity were observed. However, when phase mask orders other than +1 were absent during fabrication the features at 1552 nm were not evident.