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Study on a high-temperature optical fiber F–P acceleration sensing system based on MEMS
摘要： Vibration measurement at high temperature is of great signi?cance to monitoring the operation of major projects and mechanical equipment. As the temperature resistance of electrical vibration sensors is usually below 600 °C, it cannot meet the requirements of some high-temperature measuring conditions. This paper studies a high-temperature Fabry–Perot (F–P) acceleration sensing system with general single-mode ?ber. A high-temperature sensitive diaphragm is machined based on micro-electromechanical system (MEMS) technology and it is combined with the ?ber microstructure to enable the sensing probe to be packaged under high temperatures. According to the temperature characteristic of the length of the F–P cavity, a signal demodulation system was proposed based on the rapid automatic tracking of the quiescent operation point. The complete optical ?ber F–P acceleration sensing system conducted real-time vibration detection of high temperature casting in the foundry factory. The experimental result indicates that the optical ?ber high-temperature acceleration sensor showed a better vibration response in the working frequency of 100–1000 Hz and the relative error of the frequency measurement is less than 1.56% under normal temperatures and a high temperature of 800 °C.
关键词： Optical ?ber F–P,High-temperature,Acceleration sensor,Tunable laser source,MEMS
更新于2025-11-28 14:23:57
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Multilayer dielectric coated Fabry Perot spectral beam combiner for high power, narrowband, widely tunable laser applications
摘要： Spectral beam combination of tunable laser beams demonstrated, using a multilayer dielectric coated single cavity Fabry Perot (FP) filter. A stack of 19 layers using TiO2 and SiO2 was optimally designed and fabricated using an electron beam evaporation technique. This filter was characterized for transmission spectrum, surface morphology and laser induced damage threshold. The sharp transmission spectrum facilitated the spectral combination of closer wavelengths (< 10 nm) around 632.8 nm. This filter was utilized as an efficient spectral beam combiner as well as an amplified spontaneous emission (ASE) filter for the transmitting wavelength. This study finds direct application for tunable, multi-wavelength laser-based differential absorption lidar (DIAL) and atmospheric remote sensing applications. The application of this device was successfully demonstrated to spectrally combine high power, tunable copper vapor laser pumped dye laser beams. A mechanism to tune the FP transmission profile along with laser beam tunability was established.
关键词： Fabry Perot beam combiner,Widely tunable laser,Amplified spontaneous emission filtering,Angle tuning mechanism,Closer wavelength spectral beam combination
更新于2025-09-23 15:21:01
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Development of a composite polymer-dye medium for tunable laser emission
摘要： We demonstrate optically pumped laser medium with emission in the visible spectral range from binary solutions of Rhodamine 6G and Rhodamine B in epoxy resin as matrix without appending additional scattering centers. A frequency doubled Q-switched Nd: YAG laser was used for pumping. The generation’s behavior is similar to random laser (RL) with no external optical resonator. The in?uence of the nanostructured morphology of the medium on the laser properties was investigated by means of SEM, AFM, TEM, SAED, Spectro?uorimetry and Spectrometry. The laser emission is characterized by high intensity – energy per pulse – 300 μJ, threshold pump energy 1.7 mJ, relatively low beam divergence of 70 mrad (for RL) and spectrally narrowed major peak at 597 nm. The new gain medium was also investigated in a conventional tunable resonator. Generation with continuous tuning in the spectral range 590–610 nm was obtained. This new e?ective nanostructured medium, which shows with high optical and energy parameters, can be used in speckle-free laser imaging, time-resolved microscopy, high speed optical converters and others photonics applications.
关键词： Dye laser,Tunable laser,Broadband laser,Random laser,Epoxy resin
更新于2025-09-23 15:19:57
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Hyperfine structures and isotopic shifts of uranium transitions using tunable laser spectroscopy of laser ablation plumes
摘要： We report isotopic shifts and hyperfine structures of selected U transitions employing tunable spectroscopy viz: laser-induced fluorescence and laser absorption spectroscopy of laser ablation plumes. The plasmas were produced during ns laser ablation on a natural U metal target which contains 0.73% 235U. Our results show that isotopic shifts between 238U and 235U are entangled with hyperfine structures of 235U. Measurements obtained using laser-induced fluorescence are affected by the high absorbance of 238U. Time-resolved laser absorption spectroscopy is carried out for evaluating the optical absorption and estimating the hyperfine constants.
关键词： LIBS,Hyperfine structure,Laser absorption spectroscopy,Isotopic analysis,Uranium,Laser-induced fluorescence,Laser ablation,Tunable laser spectroscopy
更新于2025-09-23 15:19:57
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Ultrahigh resolution spectroscopy for dimethyl sulfide at the ??1- and ??8-bands by a distributed feedback interband cascade laser
摘要： The ultrahigh-resolution, air-broadened mid-infrared absorption spectrum of dimethyl sulfide (DMS) was recorded in the spectral region of 2994.17–2999.03 cm?1, where the strong ν1-/ν8-bands are located. Benefitting from the tunable laser absorption spectrometry with a distributed feedback interband cascade laser, the spectral resolution achieved 5.69 × 10?6 cm?1. The recorded spectra of DMS are very close to that in the Pacific Northwest National Laboratory (PNNL) database, however it has a much lower absorbance uncertainty of 0.38%. And the maximum relative difference of the full width at half maximum and the integrated area of spectral peaks between the recorded spectra and the PNNL data are as large as 16.7% and 27.9%, respectively, which could mainly come from the difference of the spectral resolution. The more accurate reference spectrum is hopeful to be applied to absolute measurement and remote sensing for gaseous DMS.
关键词： Tunable laser absorption spectroscopy (TLAS),Dimethyl sulfide (DMS),Ultrahigh-resolution spectrum,Interband cascade laser (ICL),Mid-infrared
更新于2025-09-23 15:19:57
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All-Fiber CO2 Sensor Using Hollow Core PCF Operating in the 2 μm Region
摘要： A realistic implementation of an all-fiber CO2 sensor, using 74 cm of hollow core photonic crystal fiber (HC-PCF) as the cavity for light/gas interaction, has been implemented. It is based on CO2 absorbance in the 2 μm region. The working range is from 2% to 100% CO2 concentration at 1 atm total pressure and the response time obtained was 10 min. Depending on the concentration level, the sensor operates at one of three different wavelengths (2003.5 nm, 1997.0 nm and 1954.5 nm) to maintain a high sensitivity across all the working range.
关键词： gas,sensor,tunable laser,carbon dioxide monitoring,fiber bragg grating,photonic crystal fiber
更新于2025-09-19 17:15:36
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Narrow-linewidth self-sweeping fiber laser with scanning range control by a tunable Lyot filter
摘要： To obtain broadly tunable narrow-linewidth generation in a self-sweeping fiber laser, we propose combining the broadband tunability of a Lyot filter and an adaptive filter based on dynamic grating. The grating is intrinsically formed in the laser active medium during the self-sweeping operation. Temperature control of the fiber Lyot filter and matching of the filter tuning and self-induced sweeping rates allows for an increase in the tuning range, from 20–42 nm in a Yb-doped fiber laser, keeping an instantaneous linewidth below the level of 20 MHz.
关键词： Lyot filter,fibre laser,tunable laser
更新于2025-09-19 17:13:59
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Blue Laser Diode System With an Enhanced Wavelength Tuning Range
摘要： A prism-based self-injection locked seamlessly tunable blue InGaN/GaN laser diode composite cavity system is presented. A rigorous analysis of this external cavity diode laser (ECDL) system is performed at two different optical feedback powers. At 130 mA low injection, the high reflection system (HRS) exhibits a record wideband tuning span of ~12.11 nm with a side-mode-suppression-ratio (SMSR) ≥ 15 dB, measuring as high as 40 dB, linewidth ≤ 110 pm, and a working power of about 3 mW. Whereas, a tuning range of 8 nm with linewidth ≤ 88 pm, SMSR ≥ 13 dB, reaching a maximum of 35 dB with 14.5 mW usable power is achieved from the low reflection system (LRS) at the same injection current. Moreover, an inverse relationship between the optical power and the tunability is observed in both the systems with a value as high as 180 mW exhibited by LRS configuration and attaining a tunability of 4.5 nm. Both systems highlight high stability even at higher injection currents and temperature. Such a robust, simple, and compact system may serve as a crucial light source in a plethora of diverse applications besides visible optical communications. To the best of our knowledge, this is the first report on a continuously tunable self-injection locked tunable laser system.
关键词： external cavity systems,Tunable Laser,self-injection locking
更新于2025-09-19 17:13:59
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An Ultra-High-SMSR External-Cavity Diode Laser with a Wide Tunable Range around 1550 nm
摘要： In this paper, a widely tunable external cavity diode laser (ECDL) with an ultra-high side mode suppression ratio (SMSR) was fabricated. Three configurations were constructed to investigate the relationship between the grating features and the SMSR. When a 1200 grooves/mm grating with a first order diffraction efficiency of 91% is utilized in the external-cavity laser system, a maximum SMSR of 65 dB can be achieved. In addition, the tunable range reaches 209.9 nm. The results show that the laser performance can be improved by proper high grating groove number and first-order diffraction efficiency.
关键词： tunable laser,side mode suppression ratio (SMSR),external cavity diode laser (ECDL),diffractive grating
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Tunable Erbium-Doped Fiber Laser Assisted by a fs-laser Introduced Random Fiber Grating
摘要： A tunable erbium-doped fiber (EDF) laser assisted by a random fiber grating introduced by an fs-laser and a tunable fiber Bragg grating is demonstrated. The tuning range is up to 4.45 nm（1548.04 -1552.49 nm）. Due to the half-opened laser cavity design and the efficient gain from the pumped EDF, the measured threshold pump power is 18 mW, and the slope efficiency is up to 13.2%.
关键词： random fiber grating,tunable laser,Erbium-doped fiber,random fiber laser
更新于2025-09-16 10:30:52