检索结果-南通市图书馆

Spectral analysis of the UFBG-based acousto optical modulator in V–I transmission matrix formalism

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第11期23卷 251-256页

作者：吴良英裴丽刘超王一群翁思俊王建帅 key laboratory of all optical network & advanced telecommunication network of emc Beijing Jiaotong Univcnersity

In this study, the V –I transmission matrix formalism(V –I method) is proposed to analyze the spectrum characteristics of the uniform fiber Bragg grating(FBG)-based acousto–optic modulators(UFBG-AOM). The simulation results demonstrate that both the amplitude of the acoustically induced strain and the frequency of the acoustic wave(AW) have an effect on the spectrum. Additionally, the wavelength spacing between the primary reflectivity peak and the secondary reflectivity peak is proportional to the acoustic frequency with the ratio 0.1425 nm/MHz. Meanwhile, we compare the amount of calculation. For the FBG whose period is M, the calculation of the V –I method is 4 ×(2M-1) in addition/subtraction,8 ×(2M- 1) in multiply/division and 2M in exponent arithmetic, which is almost a quarter of the multi-film method and transfer matrix(TM) method. The detailed analysis indicates that, compared with the conventional multi-film method and transfer matrix(TM) method, the V –I method is faster and less complex.

关键词： uniform fiber bragg grating(UFBG) acousto–optic modulator(AOM) V–I transmission matrix formalism spectrum

Switchable multi-wavelength fiber laser based on modal interference

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2015年第8期24卷 317-322页

作者：马林孙将齐艳辉康泽新简水生 key laboratory of all optical network & advanced telecommunication network of emc Beijing Jiaotong University

A comb fiber filter based on modal interference is proposed and demonstrated in this paper. Here two cascaded uptapers are used to excite the cladding mode, and a core-offset jointing point is used to act as an interference *** results show that this kind of structure possesses a comb filter property in a range of the C-band. The measured extinction ratio is better than 12 dB with an insertion loss of about 11 dB. A switchable multi-wavelength erbium-doped fiber laser based on this novel comb filter is demonstrated. By adjusting the polarization controller, the output laser can be switched among single-, dual-, and three-wavelengths with a side mode suppression ratio of better than 45 dB.

关键词： fiber laser up-taper core-offset modal interferometer

Influence of group-delay ripple on timing jitter induced by SPM and IXPM in systems with dispersion compensated by CFBG

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2007年第8期5卷 441-444页

作者：秦曦曹继红陈勇张峰简水生 key laboratory of all optical network & advanced telecommunication network of emc Beijing Jiaotong University

An analytical expression was proposed to analyze the influence of group-delay ripple （GDR） on timing jitter induced by self-phase modulation （SPM） and intra-channel cross-phase modulation （IXPM） in pseudolinear transmission systems when dispersion was compensated by chirped fiber Bragg grating （CFBG）. Effects of ripple amplitude, period, and phase on timing jitter were discussed by theoretical and numerical analysis in detail. The results show that the influence of GDR on timing jitter changes linearly with the amplitude of GDR and whether it decreases or increases the timing jitter relies on the ripple period and ripple phase. Timing jitter induced by SPM and IXPM could be suppressed totally by adjusting the relative phase between the center frequency of the pulse and the ripples.

关键词： Dispersion compensation Numerical analysis Self phase modulation Timing jitter

all-fiber modal interferometer based on an up-taper-core-offset structure for curvature sensing

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2015年第4期24卷 207-210页

作者：马林齐艳辉孙将康泽新简水生 key laboratory of all optical network and advanced telecommunication network of emc Beijing Jiaotong University

A high-sensitivity curvature sensor based on an up-taper-core-offset structure is proposed and demonstrated in this paper. Here two specially designed cascaded up-tapers with maximum diameters of 247 μm and 251 μm, respectively, are used as a cladding mode exciting component. The excited cladding modes will propagate in the cladding and re-couplers with the core mode at the core-offset jointing point. When the curvature is changed, the dip wavelength of the sensor will shift to a blue wavelength and an average curvature sensitivity of more than -12.5 nm/m^-1 is achieved within the measured curvature intervals.

关键词： curvature sensor up-taper core-offset modal interferometer

Study on pure silica core optical fibers

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2008年第1期51卷 58-64页

作者： LI Jian ZHENG Kai CHANG DeYuan WEI Huai NING TiGang FU YongJun MAO XiangQiao YAN FengPing JIAN Wei JIAN ShuiSheng key laboratory of all optical network&advanced telecommunication network of emc Institute of Lightwave TechnologyBeijing Jiaotong UniversityBeijing 100044China

An optimal refractive index profile of pure silica core optical fiber (PSCF) was de- signed, in combination with the characters of the modified chemical vapor deposi- tion (MCVD) process. Techniques of preform fabrication by a new furnace round heating MCVD process and fiber drawing process were reviewed. Difficulties in doping fluorine in silica, widening the depressed-index cladding and maintaining the index of fiber core were discussed. Methods used to overcome these difficulties were given at the same time. Additionally, the optimal refractive index profiles of PSCF were presented.

关键词： pure silica core optical fiber (PSCF) depressed index cladding modified chemical vapor deposition (MCVD) process

A simple model for approximate bandgap structure calculation of all-solid photonic bandgap fibre based on an array of rings

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2008年第1期17卷 232-237页

作者：方宏娄淑琴郭铁英姚磊李宏雷简水生 key laboratory of all optical network & advanced telecommunication network of emc Institute of Lightwave Technology Beijing Jiaotong University

A simple model for approximate bandgap structure calculation of all-solid photonic bandgap fibre based on an array of rings is proposed. In this model calculated are only the potential modes of a unit cell, which is a high-index ring in the low-index background for this fibre, rather than the whole cladding periodic structure based on Bloch＇s theorem to find the bandgap. Its accuracy is proved by comparing its results with the results obtained by using the accurate full-vector plane-wave method. High speed in computation is its great advantage over the other exact methods, because it only needs to find the roots of one-dimensional analytical expressions. And the results of this model, mode plots, offer an ideal environment to explore the basic properties of photonie bandgap clearly.

关键词： photonic bandgap fibre bandgap structure multi-layer waveguide plane-wave method

Design of broadband nearly-zero flattened dispersion highly nonlinear photonic crystal fiber

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2008年第11期6卷 821-823页

作者：娄淑琴方宏李宏雷郭铁英姚磊王立文陈卫国简水生 key Lab of all optical network and advanced telecommunication network of emc Beijing Jiaotong UniversityBeijing 100044

We propose a new structure of broadband nearly-zero flattened dispersion highly nonlinear photonic crystal fiber （PCF）. Through optimizing the diameters of the first two inner rings of air-holes and the GeO2 doping concentration of the core, the nonlinear coefficient is up to 47 W^-***^-1 at the wavelength of 1.55 um and nearly-zero flattened dispersion of ±0.5 ps/（nm·km） is achieved in the telecommunication window （1460 - 1625 nm）. Due to the use of GeO2-doped core, this innovative structure can offer not only a large nonlinear coefficient and broadband nearly-zero flattened dispersion but also low leakage losses.

关键词： Crystal atomic structure Crystal structure Crystal whiskers Dispersion (waves) Laser pulses Nonlinear optics telecommunication systems

Switchable instantaneous frequency measurement by optical power monitoring based on DP-QPSK modulator

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第4期31卷 336-347页

作者： Yu-Lin Zhu Bei-Lei Wu Jing Li Mu-Guang Wang Shi-Ying Xiao Feng-Ping Yan Institute of Lightwave Technology Key Laboratory of All Optical Network and Advanced Telecommunication of EMCBeijing Jiaotong UniversityBeijing 100044China

We propose and analyze an instantaneous frequency measurement system by using optical power monitoring technique with improved *** primary component adopted in the proposal is a dual-polarization quadrature phase shift keying(DP-QPSK) modulator which is used to modulate the microwave signal that has a designed time delay and phase *** generated optical signal is sent to polarization beam splitter(PBS) in DP-QPSK *** to the complementary transmission nature of polarization interference introduced by PBS,the frequency information is converted into the optical power and the relationship between the amplitude comparison function(ACF) and microwave frequency to be measured is ***,the frequency of the microwave signal can be easily measured through monitoring the optical powers of the two output ports of the ***,by adjusting the direct current(DC) biases of the DP-QPSK modulator instead of changing the electrical delay,the measurement range and resolution can be *** this paper,the basic principle of the instantaneous frequency measurement system is derived in detail,and simulation has been performed to investigate the resolution,the measurement range,and the influence of imperfection *** proposed scheme is wavelength-independent and its measurement range is switchable,which can avoid the laser wavelength drifting problem and thus greatly increasing the system flexibility.

关键词： microwave photonics DP-QPSK modulator instantaneous frequency measurement

Multi-wavelength fiber ring laser based on a chirped moiré fiber grating and a semiconductor optical amplifier

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2009年第6期7卷 469-471页

作者：鲁韶华许鸥冯素春简水生 Institute of Lightwave Technology Key Lab of All Optical Network and Advanced Telecommunication Network of EMCBeijing Jiaotong University

A simple and cost-effective multi-wavelength fiber ring laser based on a chirped Moire fiber grating （CMFG） and a semiconductor optical amplifier （SOA） is proposed. Stable triple-wavelength lasing oscillations at room temperature are experimentally demonstrated. The measured optical signal-to-noise ratio （SNR） reaches the highest value of 50 dB and the power fluctuation of each wavelength is less than 0.2 dB within a 1-h period. To serve as a wavelength selective element, the CMFG possesses excellent comb-like filtering characteristics including stable wavelength interval and ultra-narrow passband, and its fabrication method is easy and flexible. The lasing oscillation shows a narrower bandwidth than SOA-based multi-wavelength fiber lasers utilizing some other kinds of wavelength selective components. Methods to optimize the laser performance are also discussed.

关键词： ring length CFBG Multi-wavelength fiber ring laser based on a chirped moir fiber grating and a semiconductor optical amplifier SOA