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Influences on the bandwidth at the drop port of the add/drop filter using a fiber grating coupler by uniform and linearly chirped fiber Bragg grating

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Science China(Information Sciences) 2013年第6期56卷 39-44页

作者： FAN LinYong jianG WeiWei ZHAO RuiFeng LI jian PEI Li jian shuisheng Institute of Lightwave Technology Beijing Jiaotong University Signal & Communicaiton Research Institute China Academy of Railway SciencesBeijing 100081China

Writing a fiber Bragg grating(FBG) in an optical fiber coupler is a very effective way to implement an optical add/drop filter(OADF).In order to analyze the influences on the bandwidth at the drop port of the OADF using fiber grating-assisted mismatched coupler,a uniform FBG and a linearly chirped FBG were written on the coupler,and two different OADFs were *** fiber grating is written in a 2×2 mismatched coupler,which is fused and tapered with a standard single mode fiber(SMF) and a high germanium doped photosensitive fiber,by using a 248 nm ultraviolet *** the OADF using the uniform FBG,the 3 dB and 20 dB bandwidths are 0.1 nm and 0.3 nm,respectively;for the OADF using the linear chirped FBG,the 3 dB and 20 dB bandwidths are 0.8 nm and 2 nm,*** experimental results meet the theoretical analysis *** bandwidth at the drop port of the device can be adjusted by adjusting the chirped coefficient of the linearly chirped FBG.

关键词： optical add/drop filter fiber Bragg grating coupler optical fiber communication

Study on pure silica core optical fibers

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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

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Numerical Analysis on Transmission Characteristics of a Bragg Grating Assisted Mismatched Fiber Coupler

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Chinese Journal of Lasers 2000年第2期9卷 167-174页

作者： WEI Daoping jianG Zhong'ao ZHAO Yucheng jian shuisheng (Institute of Lightwave Technology, Northern Jiaotong Unversity, Beijing 100044, China) 北方交通大学北京

Based on mode-coupled theory, a Bragg grating assisted mismatched fiber coupler is analyzed theoretically. At the same time, a detailed numerical analysis on transmission characteristics of the coupler is carried out when it considers the arcs of two fibers in the coupling region of the coupler or not, and the optimized design on the Bragg grating assisted mismatched fiber coupler for wavelength-division multiplexing/ demultiplexing is proposed.

关键词： wavelength-division multiplexing/ demultiplexing fiber Bragg gratings mismatched fiber couplers mode-coupled theory

2500 km-10 Gbps RZ transmission system based on dispersion compensation CFBGs without electric regenerator

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Frontiers of Optoelectronics 2008年第Z2期1卷 219-222页

作者： Jihong CAO Yong CHEN Ting CHEN shuisheng jian Key Lab of All Optical Network and Advanced Telecommunication Network of EMC Beijing Jiaotong University Institute of Lightwave Technology Beijing Jiaotong University

The characteristics of chirped fiber Bragg gratings（CFBGs） are optimized so that the ripple coefficient of the power reflectivity spectrum and group time delay are less than 1 dB and |± 15| ps, group delay is about 2600 ps/nm, polarization module dispersion is very small, PMD < 2 ps,-3 dB bandwidth is about0.35 nm, and insertion loss is about 4–5 d Bm. Using dispersion compensation CFBG, a 2500 km-10 Gbps RZ optical signal transmission system on G.652 fiber was successfully demonstrated without an electric regenerator by optimizing dispersion management and loss management. The RZ optical signal was generated through a two-stage modulation method. At 2081 km, the power penalty of transmission is about 3 dB(conditions: RZ signal, BER = 10-12, PRBS = 1023-1); At 2560 km, the power penalty is about 5 dB. It is superior to the system using NRZ under the same conditions.

关键词： return to zero (RZ) signal chirped fiber Bragg grating (CFBG) dispersion compensation power penalty

Analysis of Mg content of Zn_(1-x)Mg_xO film grown on sapphire substrates by plasma-assisted molecular beam epitaxy

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Science China(Technological Sciences) 2004年第2期47卷 166-172页

作者： YAN Fengping jian shuisheng K.Ogata K.Koike S.Sasa M.Inoue M.Yano Institute of Lightwave Technology Beijing Jiaotong UniversityBeijing 100044China New Material Research Center Osaka Institute of TechnologyAsahikuOsaka535-8585Japan Bio Venture Center Osaka Institute of TechnologyAsahikuOsaka535-8585Japan

The Mg content of Zn1-xMgxO film grown on A-sapphire substrates by plasma-assisted molecular beam epitaxy is measured by inductively coupled plasma (ICP) and electronic probe microanalysis (EPMA). A theoretical model for analyzing the difference in the Mg content between Zn-rich and Zn-deficient conditions in the growth process is established, and the mathematical relation between Mg content and the temperature of the Mg cell is formulated under Zn-rich condition. The formula derived is proven to be correct by experiments.

关键词： ZnMgO film Mg content molecular beam epitaxy(MBE)

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Design and fabrication of erbium doped photosensitive fibers

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Science China(Technological Sciences) 2009年第5期52卷 1234-1241页

作者： LI jian LIU Peng LU ShaoHua WANG Jing MAO XiangQiao WEI Huai FU YongJun ZHENG Kai NING TiGang LI TangJun jian shuisheng Institute of Lightwave Technology Beijing Jiaotong UniversityBeijing 100044China Key Lab of All Optical Network&Advanced Telecommunication Network of EMC Beijing Jiaotong UniversityBeijing 100044China Physics Department of XingTai College Xingtai 054001China

A kind of erbium doped photosensitive fiber(EDPF) was proposed and fabricated,whose core was made of double layers named photosensitive layer and erbium doped *** double-layer core de-sign can overcome difficulties in fabrication of EDPF with single core design,*** conflict between the high consistency rare earth doping and high consistency germanium doping.A sample was fabri-cated through the modified chemical vapor deposition method combined with solution doping *** peak absorption coefficient was 48.80 dB/m at 1.53 μm,the background loss was lower than 0.1 dB/m,and the reflectivity of the fiber Brag gratings(FBG) written directly on the sample fiber was up to 97.3% by UV-writing ***,a C band tunable fiber laser was fabricated using the sample fiber,in which a uniform FBG was written directly on EDPFs as a reflector.A single wavelength lasing with a maximum wavelength tuning range of 1555.2―1558.0 nm was achieved *** this tuning range,the full-width at half maximum(FWHM) of the laser output was smaller than 0.015 nm and the side mode suppression ratio(SMSR) was better than 50 dB.

关键词： erbium doped fiber(EDF) photosensitivity modified chemical vapor deposition(MCVD) method solution doping technique fiber Bragg grating(FBG) fiber laser wavelength tunable

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Dispersion Compensators Based on Overlaped Linearly Chirped Fiber Gratings for DWDM Systems

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Chinese Journal of Lasers 2001年第6期10卷 18-22页

作者： LI Tangjun Ning Tigang WANG Muguang jian shuisheng (Institute of Lightwave Technology, Northern Jiaotong University, Beijing 100044, China) 北方交通大学光波所北京 100044

By introducing a convergent lens in the phase mask setup and by tilting appropriately the fiber from the phase mask, a linearly chirped fiber grating with an appropriate chirp can be obtained conveniently. Using this method, two groups of fiber gratings, each of them is composed of 8 overlaped linearly chirped fiber gratings but with different center reflection wavelength separations (～0.8 nm and ～1.6 nm, respectively) are fabricated. Experimental results show that, the compensators based on the two groups of fiber gratings can be used to compensate for the dispersion of 8×2.5 Gb/s transmission over 100 km of standard single-mode fiber for multiple channels in optical time-division multiplexing (OTDM) and densed wavelength division multiplexing (DWDM).

关键词： fiber grating OTDM DWDM

Novel algorithm for synthesis of fiber gratings

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Frontiers of Optoelectronics 2009年第3期2卷 279-284页

作者： Bo LV Ming CHEN Dan LU Taorong GONG Tangjun LI shuisheng jian Key Laboratory of All Optical Network and Advanced Telecommunication Network of EMC Beijing Jiaotong University Institute of Lightwave Technology Beijing Jiaotong University

A novel algorithm for the synthesis of fiber gratings is presented. For the first time we propose an effective optimal approach to construct a coupling coefficient function by employing 4th-order Runge-Kutta(R-K) analysis method for calculating the reflection spectra of fiber gratings. The numerical results show that with this proposed method, some required optical filters have been yielded with better features compared with other methods such as Gel'Fand-Levitan-Marchenko(GLM) *** addition, the performance of different interpolation functions particularly utilized in our algorithm, including linear-type, spline-type, and Hermit-type, are discussed in detail.

关键词： gratings inverse problem synthesis algorithm coupling coefficient function interpolation functions apodization

Photonic crystal fiber with novel dispersion properties

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Frontiers of Optoelectronics 2009年第2期2卷 170-177页

作者： Shuqin LOU Shujie LOU Tieying GUO Liwen WANG Weiguo CHEN Honglei LI shuisheng jian Key Lab of All Optical Network and Advanced Telecommunication Network of EMC Beijing Jiaotong University Shandong Weifang Huaguang Precision Machinery Co.

Our recent research on designing microstructured fiber with novel dispersion properties is reported in this paper. Two kinds of photonic crystal fibers（PCFs） are introduced first. One is the highly nonlinear PCF with broadband nearly zero flatten dispersion. With introducing the germanium-doped（Ge-doped） core into highly nonlinear PCF and optimizing the diameters of the first two inner rings of air holes, a new structure of highly nonlinear PCF was designed with the nonlinear coefficient up to 47 W–1·km–1at the wavelength 1.55 μm and nearly zero flattened dispersion of ±0.5 ps/（km·nm） in telecommunication window（1460–1625 nm）. Another is the highly negative PCF with a ring of fluorin-doped（Fdoped） rods to form its outer ring core while pure silica rods to form its inner core. The peak dispersion – 1064ps/（km·nm） in 8 nm full width at half maximum（FWHM）wavelength range and – 365 ps/（km·nm） in 20 nm（FWHM） wavelength range can be reached by adjusting the structure parameters. Then, our recent research on the fabrication of PCFs is reported. Effects of draw parameters such as drawing temperature, feed speed, and furnace temperature on the geometry of the final photonic crystal fiber are investigated.

关键词： photonic crystal fiber (PCF) nearly zero flatten dispersion high nonlinear high negative dispersion fabrication technique