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Generation of a large orbital angular momentum beam via an optical fiber winding around a curved path and its application

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Chinese Physics B 2021年第10期30卷 342-350页

作者： Wei-Han Tan Chao-Ying Zhao Yi-Chao Meng Qi-Zhi Guo Department of Physics Shanghai UniversityShanghai 200444China College of Science Hangzhou Dianzi UniversityHangzhou 310018China State Key Laboratory of Quantum optics and Quantum optics Devices Institute of Opto-ElectronicsShanxi UniversityTaiyuan 030006China Institute of fiber optics Shanghai UniversityShanghai 200444China

Many papers have been published on the study of orbital angular momentum(OAM)of the laser modes based on the Laguerre-Gaussian(LG)beam and helical phase plate or rotating cylindrical lens,and the principal ray of the LG beam remains straight *** ways are difficult to get a large OAM *** this paper,we propose a novel method to prepare a large OAM modes when the light propagates through a optical fiber winding around a curved path,and establish a theoretical framework based on the principal ray path ***,we investigate three kinds of winding ***,based on the analytical solutions and numerical calculations,we can find that the spiral body can achieve a large OAM temporal *** the same time,based on the zero OAM diffraction diagram,we can obtain an improvement of resolving power beyond Rayleigh’s ***,applying a large OAM diffraction pattern to realize 12-bitencodes,we can obtain a high-security optical information transfer system.

关键词： fiber optics orbital angular momentum(OAM) differential Fernet equation Rayleigh criterion

Research of Optical fiber Coil Winding Model Based on Large-deformation Theory of Elasticity and Its Application

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Chinese Journal of Aeronautics 2011年第5期24卷 640-647页

作者： JIA Ming YANG Gongliu School of Instrumentation Science and Opto-electronics Engineering Beihang University Beijing 100191 China

Optical fiber coil winding model is used to guide proper and high precision coil winding for fiber optic gyroscope （FOG） application. Based on the large-deformation theory of elasticity, stress analysis of optical fiber free end has been made and balance equation of infinitesimal fiber is deduced, then deformation equation is derived by substituting terminal conditions. On condition that only axial tensile force exists, approximate curve equation has been built in small angle deformation scope. The comparison of tangent point longitudinal coordinate result between theory and approximation gives constant of integration, and expression with tangent point as origin of coordinate is readjusted. Analyzing the winding parameters of an example, it is clear that the horizontal distance from the highest point of wheel to fiber tangent point has millimeter order of magnitude and significant difference with fiber tension variation, and maintains invariant when wheel radius changes. The height of tension and accurate position of tangent point are defined for proper fiber guide. For application to fiber optic gyroscope, spiral-disc winding method and nonideal deformation of straddle section are analyzed, and then spiral-disc quadrupole pattern winding method has been introduced and realized by winding system. The winding results approve that the winding model is applicable.

关键词： fibers fiber optics large-deformation fiber optic gyroscope spiral-disc winding quadrupole pattern

Pseudo working-point control measurement scheme for acoustic sensitivity of interferometric fiber-optic hydrophones

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Chinese optics Letters 2008年第5期6卷 381-383页

作者：王泽锋胡永明孟洲倪明 College of Photoelectric Science and Engineering National University of Defense Technology

A novel pseudo working-point control measurement scheme for the acoustic sensitivity of interferometric fiber-optic hydrophones is described and demonstrated. The measurement principle is introduced in detail. An experimental system, which interrogates an interferometric fiber-optic hydrophone with this method, is designed. The acoustic pressure phase sensitivity of the fiber-optic hydrophone is measured over the frequency range of 20- 2500 Hz. The measured acoustic sensitivity is about -156.5 dB re 1 rad/μPa with a fluctuation lower than ±1.2 dB, which is in good agreement with the results obtained by the method of phase generated carrier. The experimental results testify the validity of this new method which has the advantages of no electric elements in the sensing head, the simplicity of signal processing, and wide working bandwidth.

关键词： Acoustics Computer networks Electroacoustic transducers fiber optics Interferometers Interferometry Optical instruments Signal processing

An Easily Switchable Dual-Wavelength Passively Mode-Locked Erbium fiber Laser

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Chinese Physics Letters 2014年第1期31卷 84-87页

作者：黄惠昌杨通袁晓志杨中民 State Key Laboratory Luminescent Materials and Devices and Institute of Optical Communication Materials South China University of Technology Ouangzhou 510640 Special Glass fiber and Device Engineering Technology Research and Development Center of Guangdong Province Guangzhou 510640

A simple scheme of switchable dual-wavelength passively mode-locked fiber laser is demonstrated. The laser can be flexibly switched among different mode-locked states simply by tuning the cavity loss while keeping all the other cavity parameters fixed. As the cavity loss increases, the mode-locked fiber laser operates at the long-wavelength, dual-wavelength, and short-wavelength states, successively. In addition, these states can be conveniently switched without losing the mode-locked operation and the switching process is reversible as the cavity loss decreases. The mechanism is qualitatively explained by the balance between the fiber gain and the cavity loss.

关键词： fiber lasers fiber optics SOLID-state lasers WAVELENGTHS ISOSBESTIC point

A PMD-supported 100-Gb/s optical frequency-domain IM-DD transmission system

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Chinese optics Letters 2009年第8期7卷 679-682页

作者：李蔚乔耀军韩庆生张欢 Wuhan National Lab for Optoelectronic Huazhong University of Science and Technology Key Laboratory of Information Photonics and Optical Communications Ministry of EducationBeijing University of Posts and Telecommunications

A novel method for distortion-free optical pulse transmission is theoretically proposed and simulated, in which two time lenses formed by dispersion fibers and quadratic phase modulations are utilized. One is used as an optical inverse Fourier transformation （OIFT） device to transform the initial time-domain data to frequency-domain one at the transmitter and the other as an optical Fourier transformation （OFT） device to recover the data at the receiver. By using the unchanged spectral envelope in linear optical fiber communication, the initial data can be recovered. Through simulations, a 10× 100 Gb/s intensity-modulated direct-detection （IM-DD） dense wavelength division multiplexing （DWDM） system over 20000 km transmission without the compensation for polarization mode dispersion （PMD） and dispersion slope is achieved, which can be used to upgrade the current 100Gb/s IM-DD system to a 100-Gb/s one directly.

关键词： Dense wavelength division multiplexing fiber optics Fourier analysis Frequency domain analysis Light transmission Multiplexing Multiplexing equipment Optical communication Optical fibers Optical materials Polarization mode dispersion

Effects of Polarization-Maintaining Fibre Degrading on Precision of Fibre Optic Gyroscopes in Radiation Environment

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Chinese Physics Letters 2008年第4期25卷 1224-1226页

作者：肖文刘德文刘洋伊小素丛琳 School of Instrument Science and Opto-electronics Engineering Beijing University of Aeronautics and Astronautics Beijing 100083

In the space environment, the precision of fibre optic gyroscopes （FOGs） degrades because of space radiation. Photonic components of FOGs are affected by radiation, especially the polarization-maintaining （PM） fibre coil. In relation to the space radiation environment characteristic, we have carried out a series of radiation experiments on a PM fibre coil with 6OCo radiation source at different dose rates. Bazed on the experimental results, the formula between the PM-fibre loss and radiation dose rate is built, and the relation between the precision of FOG and radiation dose is obtained accordingly. The results strongly show that the precision of our FOG degrades owing to the attenuation of the polarization-maintaining fibre, which provides theoretical foundation for the radiation-resistant design of the FOG.

关键词： fiber optics GYROSCOPES RADIATION sources RADIATION

Static sensitivity calculation of a novel fiber optic biosensor

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Chinese optics Letters 2008年第12期6卷 922-924页

作者：白忠臣秦水介李静黄大顺张欣 The Key Laboratory for Photoelectric Technology and Application Guizhou University College of Science Guizhou University College of Science Guizhou University No.1 Middle School of Cheng

A novel structure of fiber optic biosensor and its principle are introduced. The sample is detected in microchannels of several microns diameter in fiber optic biosensors. The relation between the optic fiber tapered angle and the fluorescence incident angle is calculated in signal receiving part. As the sensor is a zero-order system, calculating formula of the static sensitivity is derived. When ZnSe nano-crystalline cluster is used for marking the molecules, the static sensitivity for fiber optic biosensors is calculated. At the same time, the relation between the static sensitivity and the ratio of exciting wavelength to fluorescence wavelength is presented.

关键词： fiber optics fibers Fluorescence Optical materials Signal transduction

Design of Raman-parametric fiber amplifier for wavelength division multiplex transmission system

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Chinese optics Letters 2008年第5期6卷 327-330页

作者：江晓弘姜淳章晓鸣 State Key Laboratory of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University

We optimize the novel configuration of a hybrid fiber amplifier - Raman assisted-fiber-based optical parametric amplifier （R-FOPA）, in which the parametric gain and Raman gain profiles are combined to achieve a flat composite gain profile. The pump powers and the fiber length in the hybrid amplifier are effectively optimized by genetic algorithm （GA） scheme. The optimization results indicate that the RFOPA can achieve a 200-nm flat bandwidth spectrum with the gain of 20 dB and ripple of less than 4 dB.

关键词： Computer networks Electric power transmission fiber amplifiers fiber optics Genetic algorithms Light amplifiers Microwave amplifiers Multiplexing Optimization Parametric amplifiers Parametric devices

All-fiber ring-cavity based frequency swept laser source for frequency domain OCT

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Chinese optics Letters 2010年第2期8卷 202-205页

作者：陈明惠丁志华徐磊吴彤王川史国华张雨东 State Key Lab of Modern Optical Instrumentation Zhejiang University Institute of optics and Electronics Chinese Academy of Sciences

We develop a high-speed tunable, quasi-continuous-wave laser source for frequency domain （FD） optical coherence tomography （OCT）. The laser resonance is realized within a unidirectional all-fiber ring cavity consisting of a fiber coupler, two fiber isolators, a semiconductor optical amplifier （SOA）, and a fiber Fabry- Perot tunable filter （FFP-TF） for frequency tuning. Light output from the coupler is further amplified and spectral shaped by a booster SOA terminated at both ends with two isolators. The developed laser source provides up to 8000 sweeps per second over a full-width wavelength tuning range of 120 nm at center wavelength of 1320 nm with an average power of 9 mW, yielding an axial resolution of 13.6μm in air and a maximum sensitivity of about 112 dB for OCT imaging. The instantaneous linewidth is about 0.08 nm, enabling OCT imaging over an axial range of 3.4 mm in air. For optimization consideration based on this custom-built swept laser, experimental study on imaging quality relevant parameters of the swept laser with sine and ramp driving waveforms to the FFP-TF is conducted, and investigation of the swept laser on the cavity length is done. Implementing the laser source in our established swept source based OCT （SS-OCT） system, real-time structural imaging of biological tissue is demonstrated.

关键词： Coherent light fiber optics fibers Frequency domain analysis Light amplifiers Optoelectronic devices Tomography Tuning