Solid-core silica photonic crystal fiber is proposed borrowing the concept of golden ratio (1.618) and keeping it between pitch and air hole diameter Λ/d in a subset of six rings of air-holes with hexagonal arrangeme...Solid-core silica photonic crystal fiber is proposed borrowing the concept of golden ratio (1.618) and keeping it between pitch and air hole diameter Λ/d in a subset of six rings of air-holes with hexagonal arrangement. In the case when we have a pitch equal to one micron (Λ = 1 μm), we need air-holes diameters d = 0.618 μm in order to achieve two zero dispersion wavelength (ZDW) points at 725 nm and 1055 nm;this gives us the possibility to use the fiber for supercontinuum generation, by pumping close to that points, pulse compression or reshaping. We analyzed a series of fibers using this relation and showed the possibilities of tunable ZDW in a wide range of wavelengths from 725 nm to 2000 nm, with low losses and small effective area. In agreement with the ZDW point needed, the geometry of the structure can be modified to the point of having only three rings of air holes that surround the solid core with low losses and good confinement mode. The design proposed here is analyzed using the finite element method with perfectly matched layers, including the material dispersion directly into the model applying the Sellmeier’s equation.展开更多
Metalenses with achromatic performance offer a new opportunity for high-quality imaging with an ultracompact configuration;however,they suffer from complex fabrication processes and low focusing efficiency.In this stu...Metalenses with achromatic performance offer a new opportunity for high-quality imaging with an ultracompact configuration;however,they suffer from complex fabrication processes and low focusing efficiency.In this study,we propose an efficient design method for achromatic microlenses on a wavelength scale using materials with low dispersion,an adequately designed convex surface,and a thickness profile distribution.By taking into account the absolute chromatic aberration,relative focal length shift(FLS),and numerical aperture(NA),microlens with a certain focal length can be realized through our realized map of geometric features.Accordingly,the designed achromatic microlenses with low-dispersion fused silica were fabricated using a focused ion beam,and precise surface profiles were obtained.The fabricated microlenses exhibited a high average focusing efficiency of 65%at visible wavelengths of 410-680 nm and excellent achromatic capability via white light imaging.Moreover,the design exhibited the advantages of being polarization-insensitive and near-diffraction-limited.These results demonstrate the effectiveness of our proposed achromatic microlens design approach,which expands the prospects of miniaturized optics such as virtual and augmented reality,ultracompact microscopes,and biological endoscopy.展开更多
Because magnetic moment is spatial in classical magnetostatics, we progress beyond the axiomatic concept of the point particle electron in physics. Orbital magnetic moment is well grounded in spherical harmonics in a ...Because magnetic moment is spatial in classical magnetostatics, we progress beyond the axiomatic concept of the point particle electron in physics. Orbital magnetic moment is well grounded in spherical harmonics in a central field. There, quantum numbers are integral. The half-integral spinor moment appears to be due to cylindrical motion in an external applied magnetic field;when this is zero , the spin states are degenerate. Consider lifting the degeneracy by diamagnetism in the cylindrical magnetic field: a uniquely derived electronic magnetic radius shares the identical value to the Compton wavelength.展开更多
A simple two-section polarization mode dispersion(PMD) compensator is proposed for multichannel PMD compensation, which can compensate two or even more channels simultaneously. Because of the statistical characteristi...A simple two-section polarization mode dispersion(PMD) compensator is proposed for multichannel PMD compensation, which can compensate two or even more channels simultaneously. Because of the statistical characteristics and the frequency-dependence of PMD, for current single mode fiber with moderate PMD, the probability that all channels are severely degraded at the same time is extremely small, which makes it possible to compensate a dense wavelength division multiplexing(DWDM) transmission system with moderate PMD using this compensator. It is shown that the outage probability of a 40×43 Gb/s DWDM transmission system using this compensator is decreased significantly from 3.6×10-3 to 3.6×10-5.展开更多
We read the original article by Nuis, et al. and the reply by Dogan, et al. with great interest. Nuis, et al. examined whether transcatheter aortic valve implantation （TAVI） in patients suffering from severe aortic ...We read the original article by Nuis, et al. and the reply by Dogan, et al. with great interest. Nuis, et al. examined whether transcatheter aortic valve implantation （TAVI） in patients suffering from severe aortic stenosis led to changes in corrected QT dispersion （cQTD）, previously used to predict arrhythmic risk. Dogan, et al. proposed that a different marker, transmural dispersion of repolariza- tion （TDR）, has better accuracy in risk prediction.展开更多
A number of researchers haw reported discrepancies between surface resistance （SR） measurements and classical theoretical predictions in normal metals for millimetre wavelengths （MW）. In this paper, a rigorous mod...A number of researchers haw reported discrepancies between surface resistance （SR） measurements and classical theoretical predictions in normal metals for millimetre wavelengths （MW）. In this paper, a rigorous model is developed for analysing SR of normal metals. This model is based on quantum mechanical analysis of the spatial dispersion within the metal. We use the model to predict SR and eliminate the discrepancies between SR measurements and classical theoretical predictions in normal metals for MW. Moreover, we have compared the results of this model with that of the classical skin-effect model and classical relaxation-effect model. Our analysis shows that the conductivity is not only frequency- but also wave-vector-dependent for MW. We demonstrate that our model has good quantitative agreement with the published experimental data for the room temperature surface resistance of normal metals for MW.展开更多
The modulation phase shift method was used to measure chromatic dispersion in a standard single mode fiber for telecommunication. The modulation phase difference of the transmitted light at the wavelength of 1532.16 n...The modulation phase shift method was used to measure chromatic dispersion in a standard single mode fiber for telecommunication. The modulation phase difference of the transmitted light at the wavelength of 1532.16 nm modulated by a radio frequency signal was measured, relative to the transmitted light at the wavelength of 1549.33 nm modulated by the same signal. By introducing a reference light at the wavelength of 1310 nm, a 1310/1550 nm wavelength division multiplexing was used instead of the high cost dense wavelength division multiplexing. In the experiment, two testing lights were coupled with the reference light to the fiber spools of different lengths, respectively. By finite difference method, the chromatic dispersion between the two testing lights was measured, and the fixed errors generated during transmission were less than 0.5 ps/(nm·km).展开更多
In order to reduce the four-wave mixing crosstalk and avoid the signal waveform distortion in long-haul dense-wavelength division multiplexing systems,helpful methods on how to choose suitable local parameters in high...In order to reduce the four-wave mixing crosstalk and avoid the signal waveform distortion in long-haul dense-wavelength division multiplexing systems,helpful methods on how to choose suitable local parameters in higher-order dispersion managed line are presented, which are used to increase the system capacity and improve the system performances.展开更多
A novel flat-top and low-dispersion optical interleaver using ring cavities （RCs） in a Mach-Zehnder interferometer （MZI） is proposed. It is composed of eight mirrors and two nested prism pairs. Each prism and the ...A novel flat-top and low-dispersion optical interleaver using ring cavities （RCs） in a Mach-Zehnder interferometer （MZI） is proposed. It is composed of eight mirrors and two nested prism pairs. Each prism and the two mirrors behave as a RC. Phase shift of RC is a periodic function of the frequency of the input light which acts as a phase dispersive mirror. The two phase shifts needed to achieve a flat-top spectral passband are provided by Fresnel reflectivities at the prism-air interface of the two RCs. The optimum interface reflectivities for flat passband, high isolation and low dispersion can be obtained only by choosing an appropriate material for the prism in each RC. The proposed interleaver in a 25 GHz channel spacing application exhibits a 0.5 dB passband greater than 24 GHz （96% of the spacing）, a 30 dB stopband greater than 21.2 GHz （84.8% of the spacing）, a channel isolation higher than 32 dB and chromatic dispersion ±50 ps/nm within the range of center-frequency ：t：2 GHz ITU passband.展开更多
In recent years, the booming band- width demands of dedicated mobile services have driven the rapid development of optical transport networks （OTNs）. Through the in- novative use of emerging coherent optical communi...In recent years, the booming band- width demands of dedicated mobile services have driven the rapid development of optical transport networks （OTNs）. Through the in- novative use of emerging coherent optical communication technology and the advance- ment of microelectronics technology, the new-generation 100Gb/s transport technology offers a high line rate and unprecedented re- silience to optical transmission impairments. This paper overviews the bandwidth demands of China Mobile driven by the upcoming roll- out of Time Division-Long Term Evolution （TD-LTE） and presents the 100Gb/s trials at China Mobile that were used to verify the performance of a lOOGb/s system. China Mo- bile＇s considerations, which were based on the trial results, regarding the deployment of lOOGb/s transport systems are introduced, and the requirements of China Mobile for the evo- lution of lOOGb/s transport systems are sum- marized.展开更多
This work presents a numerical investigation of the self-steepening（SS） effect on the soliton spectral tunneling（SST） effect in a photonic crystal fiber（PCF） with three zero dispersion wavelengths. Interestingly...This work presents a numerical investigation of the self-steepening（SS） effect on the soliton spectral tunneling（SST） effect in a photonic crystal fiber（PCF） with three zero dispersion wavelengths. Interestingly, the spectral range and flatness can be flexibly tuned by adjusting the SS value. When the SS coefficient increases, the energy between solitons and dispersion waves is redistributed, and the red-shifted soliton forms earlier in the region of long wavelength anomalous dispersion. As a consequence, the SST becomes more obvious. The findings of this work provide interesting insights in regard to the impact of the SST effect on tailored supercontinuum generation.展开更多
We report on the generation of dual-wavelength dissipative solitons in a passively mode-locked fibre laser with a net normal dispersion using the nonlinear polarization rotation （NPR） technique. Taking the intrinsic...We report on the generation of dual-wavelength dissipative solitons in a passively mode-locked fibre laser with a net normal dispersion using the nonlinear polarization rotation （NPR） technique. Taking the intrinsic advantage of the intracavity birefringence-induced spectral filtering effect in the NPR-based ring laser cavity, the dual-wavelength dissipative solitons are obtained. In addition, the wavelength separation and the lasing location of the dual-wavelength solitons can be flexibly tuned by changing the orientation of the polarization controller.展开更多
All-optical wavelength conversion of 10-Gb/s signal based on four-wave mixing is experimentally demonstrated in a 30-m-long dispersion-flattened microstructure fiber with small positive dispersion. For an average pump...All-optical wavelength conversion of 10-Gb/s signal based on four-wave mixing is experimentally demonstrated in a 30-m-long dispersion-flattened microstructure fiber with small positive dispersion. For an average pump power of 26 dBm, the conversion efficiency was around -19.5 dB with the fluctuation less than ±1.4 dB, covering a conversion bandwidth of 20 nm. The eye diagram of the converted signal shows good eye opening.展开更多
The influence of the wavelength dispersion on the temperature accuracy of the Raman distributed temperature sensor system （RDTS） is analyzed in detail, and a simple correction algorithm is proposed to compensate the...The influence of the wavelength dispersion on the temperature accuracy of the Raman distributed temperature sensor system （RDTS） is analyzed in detail, and a simple correction algorithm is proposed to compensate the fiber position error caused by the wavelength dispersion. The principle of the proposed algorithm is described theoretically, and the correction on each point along the entire fiber is realized. Temperature simulation results validate that the temperature distortion is corrected and the temperature accuracy is effectively improved from ＋5 ℃ to ±1 ℃.展开更多
文摘Solid-core silica photonic crystal fiber is proposed borrowing the concept of golden ratio (1.618) and keeping it between pitch and air hole diameter Λ/d in a subset of six rings of air-holes with hexagonal arrangement. In the case when we have a pitch equal to one micron (Λ = 1 μm), we need air-holes diameters d = 0.618 μm in order to achieve two zero dispersion wavelength (ZDW) points at 725 nm and 1055 nm;this gives us the possibility to use the fiber for supercontinuum generation, by pumping close to that points, pulse compression or reshaping. We analyzed a series of fibers using this relation and showed the possibilities of tunable ZDW in a wide range of wavelengths from 725 nm to 2000 nm, with low losses and small effective area. In agreement with the ZDW point needed, the geometry of the structure can be modified to the point of having only three rings of air holes that surround the solid core with low losses and good confinement mode. The design proposed here is analyzed using the finite element method with perfectly matched layers, including the material dispersion directly into the model applying the Sellmeier’s equation.
基金supported by grants from the National Key Research and Development Program of China(2022YFB3806000)the National Natural Science Foundation of China(52325208 and 11974203)the Beijing Municipal Science and Technology Project(Z191100004819002).
文摘Metalenses with achromatic performance offer a new opportunity for high-quality imaging with an ultracompact configuration;however,they suffer from complex fabrication processes and low focusing efficiency.In this study,we propose an efficient design method for achromatic microlenses on a wavelength scale using materials with low dispersion,an adequately designed convex surface,and a thickness profile distribution.By taking into account the absolute chromatic aberration,relative focal length shift(FLS),and numerical aperture(NA),microlens with a certain focal length can be realized through our realized map of geometric features.Accordingly,the designed achromatic microlenses with low-dispersion fused silica were fabricated using a focused ion beam,and precise surface profiles were obtained.The fabricated microlenses exhibited a high average focusing efficiency of 65%at visible wavelengths of 410-680 nm and excellent achromatic capability via white light imaging.Moreover,the design exhibited the advantages of being polarization-insensitive and near-diffraction-limited.These results demonstrate the effectiveness of our proposed achromatic microlens design approach,which expands the prospects of miniaturized optics such as virtual and augmented reality,ultracompact microscopes,and biological endoscopy.
文摘Because magnetic moment is spatial in classical magnetostatics, we progress beyond the axiomatic concept of the point particle electron in physics. Orbital magnetic moment is well grounded in spherical harmonics in a central field. There, quantum numbers are integral. The half-integral spinor moment appears to be due to cylindrical motion in an external applied magnetic field;when this is zero , the spin states are degenerate. Consider lifting the degeneracy by diamagnetism in the cylindrical magnetic field: a uniquely derived electronic magnetic radius shares the identical value to the Compton wavelength.
基金National Nature Science Foundation of China(60320130174)
文摘A simple two-section polarization mode dispersion(PMD) compensator is proposed for multichannel PMD compensation, which can compensate two or even more channels simultaneously. Because of the statistical characteristics and the frequency-dependence of PMD, for current single mode fiber with moderate PMD, the probability that all channels are severely degraded at the same time is extremely small, which makes it possible to compensate a dense wavelength division multiplexing(DWDM) transmission system with moderate PMD using this compensator. It is shown that the outage probability of a 40×43 Gb/s DWDM transmission system using this compensator is decreased significantly from 3.6×10-3 to 3.6×10-5.
文摘We read the original article by Nuis, et al. and the reply by Dogan, et al. with great interest. Nuis, et al. examined whether transcatheter aortic valve implantation （TAVI） in patients suffering from severe aortic stenosis led to changes in corrected QT dispersion （cQTD）, previously used to predict arrhythmic risk. Dogan, et al. proposed that a different marker, transmural dispersion of repolariza- tion （TDR）, has better accuracy in risk prediction.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 90201011 and 10174057）, the Key Project of Chinese Ministry of Education （Grant No 2005-105148） and The 0verseas Scholarship Program of UESTC （University of Electronic Science and Technology of China）.The work was performed at the Imperial College, London. It is a great pleasure to acknowledge the helpful discussions with Dr S. Lucyszyn during the course of this work.
文摘A number of researchers haw reported discrepancies between surface resistance （SR） measurements and classical theoretical predictions in normal metals for millimetre wavelengths （MW）. In this paper, a rigorous model is developed for analysing SR of normal metals. This model is based on quantum mechanical analysis of the spatial dispersion within the metal. We use the model to predict SR and eliminate the discrepancies between SR measurements and classical theoretical predictions in normal metals for MW. Moreover, we have compared the results of this model with that of the classical skin-effect model and classical relaxation-effect model. Our analysis shows that the conductivity is not only frequency- but also wave-vector-dependent for MW. We demonstrate that our model has good quantitative agreement with the published experimental data for the room temperature surface resistance of normal metals for MW.
基金Doctoral Foundation of Education Ministry of China(No 20040056008) National Natural Science Foundation ofChina (No 50539060)
文摘The modulation phase shift method was used to measure chromatic dispersion in a standard single mode fiber for telecommunication. The modulation phase difference of the transmitted light at the wavelength of 1532.16 nm modulated by a radio frequency signal was measured, relative to the transmitted light at the wavelength of 1549.33 nm modulated by the same signal. By introducing a reference light at the wavelength of 1310 nm, a 1310/1550 nm wavelength division multiplexing was used instead of the high cost dense wavelength division multiplexing. In the experiment, two testing lights were coupled with the reference light to the fiber spools of different lengths, respectively. By finite difference method, the chromatic dispersion between the two testing lights was measured, and the fixed errors generated during transmission were less than 0.5 ps/(nm·km).
文摘In order to reduce the four-wave mixing crosstalk and avoid the signal waveform distortion in long-haul dense-wavelength division multiplexing systems,helpful methods on how to choose suitable local parameters in higher-order dispersion managed line are presented, which are used to increase the system capacity and improve the system performances.
基金Projet supported by the National Natural Science Foundation of China (Grant No.10804070)the Innovation Program of Education Commission of Shanghai Municipality (Grant No.09YZ06)the Shanghai Leading Academic Discipline Project (Grant No.S30108)
文摘A novel flat-top and low-dispersion optical interleaver using ring cavities （RCs） in a Mach-Zehnder interferometer （MZI） is proposed. It is composed of eight mirrors and two nested prism pairs. Each prism and the two mirrors behave as a RC. Phase shift of RC is a periodic function of the frequency of the input light which acts as a phase dispersive mirror. The two phase shifts needed to achieve a flat-top spectral passband are provided by Fresnel reflectivities at the prism-air interface of the two RCs. The optimum interface reflectivities for flat passband, high isolation and low dispersion can be obtained only by choosing an appropriate material for the prism in each RC. The proposed interleaver in a 25 GHz channel spacing application exhibits a 0.5 dB passband greater than 24 GHz （96% of the spacing）, a 30 dB stopband greater than 21.2 GHz （84.8% of the spacing）, a channel isolation higher than 32 dB and chromatic dispersion ±50 ps/nm within the range of center-frequency ：t：2 GHz ITU passband.
文摘In recent years, the booming band- width demands of dedicated mobile services have driven the rapid development of optical transport networks （OTNs）. Through the in- novative use of emerging coherent optical communication technology and the advance- ment of microelectronics technology, the new-generation 100Gb/s transport technology offers a high line rate and unprecedented re- silience to optical transmission impairments. This paper overviews the bandwidth demands of China Mobile driven by the upcoming roll- out of Time Division-Long Term Evolution （TD-LTE） and presents the 100Gb/s trials at China Mobile that were used to verify the performance of a lOOGb/s system. China Mo- bile＇s considerations, which were based on the trial results, regarding the deployment of lOOGb/s transport systems are introduced, and the requirements of China Mobile for the evo- lution of lOOGb/s transport systems are sum- marized.
基金supported by the National Natural Science Foundation of China(Nos.61275137 and 61571186)the Natural Science Foundation of Hunan Province of China(No.2018JJ2061)
文摘This work presents a numerical investigation of the self-steepening（SS） effect on the soliton spectral tunneling（SST） effect in a photonic crystal fiber（PCF） with three zero dispersion wavelengths. Interestingly, the spectral range and flatness can be flexibly tuned by adjusting the SS value. When the SS coefficient increases, the energy between solitons and dispersion waves is redistributed, and the red-shifted soliton forms earlier in the region of long wavelength anomalous dispersion. As a consequence, the SST becomes more obvious. The findings of this work provide interesting insights in regard to the impact of the SST effect on tailored supercontinuum generation.
基金supported by the National Natural Science Foundation of China(Grant No.11074078)the Specialized Research Fund for the Doctoral Program of Higher Education,China(Grant No.20094407110002)+1 种基金the Foundation for Distinguished Young Talents in Higher Education of Guangdong,China(Grant No.C10183)the Key Program for Scientific and Technological Innovations of Higher Education Institutes in Guangdong Province,China(Grant No.cxzdlOll)
文摘We report on the generation of dual-wavelength dissipative solitons in a passively mode-locked fibre laser with a net normal dispersion using the nonlinear polarization rotation （NPR） technique. Taking the intrinsic advantage of the intracavity birefringence-induced spectral filtering effect in the NPR-based ring laser cavity, the dual-wavelength dissipative solitons are obtained. In addition, the wavelength separation and the lasing location of the dual-wavelength solitons can be flexibly tuned by changing the orientation of the polarization controller.
基金This work was supported by the National Basic Research Program of China(No.2003CB314906)the Foundation for Key Program of Ministry of Education,P.R.China(No.104046).
文摘All-optical wavelength conversion of 10-Gb/s signal based on four-wave mixing is experimentally demonstrated in a 30-m-long dispersion-flattened microstructure fiber with small positive dispersion. For an average pump power of 26 dBm, the conversion efficiency was around -19.5 dB with the fluctuation less than ±1.4 dB, covering a conversion bandwidth of 20 nm. The eye diagram of the converted signal shows good eye opening.
基金This work was supported by Natural Science Foundation of China （60977058）, Science Fund for Distinguished Young Scholars of Shandong Province of China （JQ200819）, Independent Innovation Foundation of Shandong University （IIFSDU2010JC002＆2012JC015）, and promotive research fund for excellent young and middle-aged scientists of Shandong Province （BS2010DX028）.
文摘The influence of the wavelength dispersion on the temperature accuracy of the Raman distributed temperature sensor system （RDTS） is analyzed in detail, and a simple correction algorithm is proposed to compensate the fiber position error caused by the wavelength dispersion. The principle of the proposed algorithm is described theoretically, and the correction on each point along the entire fiber is realized. Temperature simulation results validate that the temperature distortion is corrected and the temperature accuracy is effectively improved from ＋5 ℃ to ±1 ℃.
