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Synthesis of Fiber bragg gratings with Right-Angled Triangular Spectrum

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Chinese Physics Letters 2010年第5期27卷 131-133页

作者：李莉莎冯选旗 Department of Physics Northwest University Xi'an 710068

The spectrum shape of conventional fiber bragg gratings is near-rectangular. By means of a discrete layer peeling method we numerically study fiber bragg gratings with right-angled triangular spectrum. Fiber bragg grating structures with single- and multi-channel right-angled triangular spectra are synthesized. These kinds of devices provide potential applications in wavelength interrogation in optical sensor systems.

关键词： OPTICAL fibers bragg gratings SPECTRUM analysis OPTICAL detectors POTENTIAL theory (Physics)

Study on Multiplexing Ability of Identical Fiber bragg gratings in a Single Fiber

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Chinese Journal of Aeronautics 2011年第5期24卷 607-612页

作者： LIU Jiansheng ZHANG Jing LI Xin ZHENG Zheng School of Electronics and lnformation Engineering Beihang University Beijing 100191 China

The multiplexing ability of a novel multiplexing fiber bragg grating （FBG） method based on Optical Time Domain Reflecto meter （OTDR） and Time Division Multiplexing TDM technologies has been theoretically analyzed and studied. This method permits the interrogation of hundreds of identical FBGs with low reflectivity in a single fiber, making the FBG sensors more applicable in the aerospace health monitoring engineering. The analysis shows that the multiplexing ability can be greatly improved if the FBG reflectivity is sufficiently low. And hence, an inexpensive large-scale distributed sensing system based on this method can be realized, When evaluating the multiplexing ability of this system, we propose for the first time that the interference effect of multi-reflections among FBGs should be taken into consideration.

关键词： bragg gratings multiplexing low reflectivity multi-reflection interference effect

Field-programmable gate array-based large-capacity sensing network with 1642 ultra-weak fiber bragg gratings

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Chinese Optics Letters 2016年第1期14卷 45-48页

作者：王治文泓桥胡宸源白巍戴玉堂 National Engineering Laboratory for Fiber Optic Sensing Technology Wuhan University of Technology Key Laboratory of Fiber Optic Sensing Technology and Information Processing Ministry of EducationWuhan University of Technology

A field-programmable gate array （FPGA）-based large-capacity sensing network with ultra-weak fiber bragg gratings （FBGs） is proposed and experimentally studied. The demodulation system is constructed to interrogate 1642 serial time-division-multiplexing FBGs with a peak refleetivity of about -40 dB and equal separations of 2.5 m. Two semiconductor optical amplifiers and an InGaAs linear sensor array controlled by an FPGA are introduced to the demodulation system to achieve fast, precise, and flexible interrogation. The low crosstalk and spectral distortion axe investigated through both theoretical analysis and experiments.

关键词： bragg gratings Demodulation Fiber bragg gratings Light amplifiers Logic gates Optical variables measurement Reconfigurable hardware Semiconductor optical amplifiers Time division multiplexing

Fabrication of Tailored bragg gratings by the Phase Mask Dithering/Moving Technique

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Photonic Sensors 2013年第1期3卷 81-96页

作者： Miguel MELO Paulo V. S. MARQUES Department of Physics and Astronomy Faculty of Sciences University of Porto Rua do Campo Alegre 687 4169-007Porto Portugal INESC TEC Rua do Campo Alegre 687 4169-007 Porto Portugal

The most relevant aspects related to the phase mask dithering/moving method for the fabrication of complex bragg grating designs are reviewed. Details for experimental implementation of this technique is presented, including theoretical analysis of the calibration functions for the correct dither/displacement. Results from tailored bragg grating structures fabricated by this method are shown. Apodized bragg gratings with modeled spatial profiles were implemented, resulting in side mode suppression levels of more than 20 dB in gratings showing transmission filtering level higher than 30 dB. Chirped gratings with the spectral bandwidth up to 4 nm, π-shift and sampled bragg gratings with equalized peaks equally spaced by 0.8 nm （100 GHz） were also fabricated.

关键词： bragg gratings optical fiber filters optical fiber communications optical fiber sensors

Birefringent bragg gratings in Highly-Nonlinear Photonic Crystal Fiber

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Journal of Electronic Science and Technology of China 2008年第4期6卷 426-428页

作者： Kevin. Cook John. Canning John. Holdswowth Interdisciplinary Photonics Laboratories School of Chemistry University of Sydney NSW 2006 Australia the School of Mathematical and Physical Sciences University of Newcastle Callaghan NSW 2308 Australia

Efficient writing of bragg gratings in 12-ring highly-nonlinear photonie crystal fibers is described. Experimental and numerical investigations are performed to reveal the optimum angle for coupling UV writing light to the core. Furthermore, we show that the formation of a strongly briefringent grating is at a particular angle of orientation.

关键词： bragg gratings fiber optics photonic crystal fiber.

Coupling characteristics of laterally coupled gratings with slots

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Chinese Physics B 2022年第11期31卷 352-357页

作者： Kun Tian Yonggang Zou Linlin Shi He Zhang Yingtian Xu Jie Fan Hui Tang Xiaohui Ma State Key Laboratory on High Power Semiconductor Lasers Changchun University of Science and TechnologyChangchun 130022China

Laterally-coupled ridge-waveguide distributed feedback lasers fabricated without epitaxial regrowth steps have the advantages of process simplification and low *** present a laterally coupled grating with *** slots etched between the ridge and grating area are designed to suppress the lateral diffusion of carriers and to reduce the influence of the aspect-ratio-dependent-etching effect on the grating morphology in the etching ***,the grating height in this structure can be decreased to lower the aspect ratio significantly,which is advantageous over the conventional laterally coupled ridge waveguide *** effects of five main structural parameters on the coupling characteristics of gratings are studied by MODE *** is found that varying the lateral width of the grating can be used as an effective way to tune the coupling strength;narrow slots(100 nm and 300 nm)and wide ridge(2μm–4μm)promote the stability of grating coupling coefficient and device *** is important to note that the grating bottom should be fabricated *** comparative study of carrier distribution and mode field distribution shows that the introduction of narrow slots can strengthen the competitive advantage and stability of the fundamental mode.

关键词： bragg gratings distributed feedback(DFB)lasers coupling coefficient mode field distribution

Magneto-Optic Fiber gratings Useful for Dynamic Dispersion Management and Tunable Comb Filtering

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Chinese Physics Letters 2010年第6期27卷 225-228页

作者： WU Bao-Jian LU Xin QIU Kun Key Lab of Broadband Optical Fiber Transmission and Communication Networks of the Ministry of Education University of Electronic Science and Technology of China Chengdu 611 731

Intelligent control of dispersion management and tunable comb filtering in optical network appfications can be performed by using magneto-optic fiber bragg gratings （MFBGs）. When a nonuniform magnetic field is applied to the MFBG with a constant grating period, the resulting grating response is equivalent to that of a conventional chirped grating. Under a linearly nonuniform magnetic field along the grating, a linear dispersion is achieved in the grating bandgap and the maximal dispersion slope can come to 1260ps/nm2 for a l0-mm-long fiber grating at 1550nm window. Similarly, a Gaussian-apodizing sarnpled MFBG is also useful for magnetically tunable comb filtering, with potential application to clock recovery from return-to-zero optical signals and optical carrier tracking.

关键词： MAGNETOOPTICS bragg gratings DISPERSION COMB filters OPTICAL communications MAGNETIC fields GAUSSIAN processes SIGNAL processing

Narrow Linewidth Tm^3＋-Doped Large Core Fiber Laser Based on a Femtosecond Written Fiber bragg Grating

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Chinese Physics Letters 2010年第7期27卷 147-149页

作者：张云军王巍周仁来宋诗非田义王月珠 National Key Laboratory of Tunable Laser Technology Harbin Institute of Technology Harbin 150001

A diode laser （LD） clad-pumped narrow linewidth all-fiber Tm^3＋-doped fiber laser is reported with a maximal output power of 27W at 1.947μm. By successively splicing an LD pigtail fiber, a single-mode Tm^3＋-doped fiber, and a multi-mode Tm^3＋-doped fiber, the fiber laser has 70pm narrow linewidth output, and a high slope efficiency of nearly 47.5% with respect to the launched pump power. The high reflectivity fiber bragg gratings, which are directly written into the single-mode Tm^3＋-doped fiber core by the 800nm femtosecond pulsed laser, act as the high reflectivity coupler. The output laser has diffraction-limited beam quality with a factor M^2 of 1.29, when the output laser power is nearly 27W.

关键词： THULIUM isotopes SEMICONDUCTOR doping FEMTOSECOND lasers FIBERS LASER materials bragg gratings DIFFRACTION gratings

A Multilayered Configuration Broadband Polarization Insensitive Reflector Utilizing a Multi-Subpart Profile Grating Structure

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Chinese Physics Letters 2010年第7期27卷 154-156页

作者：吴华明侯金郜定山周治平 State Key Laboratory of Advanced Optical Communication Systems and Networks Peking University Beijing 100871 Wuhan National Laboratory for Optoelectronics School of Optoelectronie Science and Engineering Huazhong University of Science and Technology Wuhan 430074

A multilayered configuration broad bandwidth polarization insensitive reflector realized by a multi-subpart profile grating structure is presented. The properties of the reflector are investigated by rigorous coupled-wave analysis. It is shown that over a broadband spectrum of 1.62-1.76μm, the reflector demonstrates high reflectivity （R 〉 99%）, low polarization-dependent loss （PDL〈 0.02 dB） and good angular insensitivity of about 29.6% for both transverse electric and transverse magnetic polarized waves.

关键词： POLARIZATION spectroscopy bragg gratings LIGHTING reflectors BROADBAND communication systems REFLECTANCE WAVE analysis