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- 2020
- 2019
- 2018
- fast processes in solids
- femtosecond interferometry
- femtosecond laser radiation
- Materials characterization
- laser additive manufacturing
- selective laser sintering
- Additive manufacturing
- selective laser melting
- plasmonic nanostructures
- melt
- Optoelectronic Information Science and Engineering
- Mechanical Engineering
- Electronic Science and Technology
- NXP Semiconductors
- Prokhorov General Physics Institute, Russian Academy of Sciences; National Research Nuclear University MEPhI
- University of Johannesburg
- Université Grenoble Alpes
- Université de Toulouse
- Vladimir State University
- SCREEN SPE
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An optical angle sensor based on chromatic dispersion with a mode-locked laser source
摘要： This paper proposes a new optical angle sensor, in which a mode-locked laser is employed as the light source, and chromatic dispersion of a collimator objective is utilized to detect the angular displacement of a target of interest. In the proposed method, each of the optical modes in the femtosecond laser beam reflected from the reflector mounted on a target of interest is separated from the others by chromatic dispersion of a collimator objective to generate a group of focused laser beams that can be utilized as the scale for measurement of an angular displacement of the target. By detecting the change in peak frequency in optical spectra obtained by the photodetector, a small angular displacement can be measured. In this paper, as the first step of research, a prototype optical setup is developed, and some basic experiments are carried out to demonstrate the feasibility of the proposed method for measurement of angular displacement.
关键词： Chromatic dispersion,Angular displacement,Angle measurement,Optical frequency comb,Laser autocollimation
更新于2025-11-28 14:24:03
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Switchable, tunable and highly stable multi-wavelength fiber laser based on a spectral filter
摘要： In this work, a switchable and tunable multi-wavelength erbium-doped fiber laser based on a spectral filter is presented. Here, the filter is formed by polymer and silicon layers at the tip of an optical fiber. The laser emission wavelengths are mainly determined by the position where the most intense fringes of the reflectivity spectrum of the filter occurs. Moreover, the number of laser emissions are controlled and switched by using a variable optical attenuator inserted into the laser cavity. In this way, single-, dual-, triple-, and quadruple-laser emissions can be obtained within the long operating span from ~1526–~1565 nm. Additionally, the multi-wavelength laser emissions had a side mode suppression ratio ?36.48 dBm, a minimum wavelength spacing of ~3.6 nm, and the best peak power difference was 0.45 dB. Besides, the wavelength shift and peak power fluctuation were ?0.095 nm and ?3.14 dB, respectively, over half an hour. Finally, the emissions of the multi-wavelength laser can be tuned within a tunable range of 2.93 nm by taking advantage of some thermal properties of the Si and polymer layers.
关键词： multi-wavelength fiber laser,tunable,switchable
更新于2025-11-28 14:24:03
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Mega-Hertz repetition rate broadband nano-second pulses from an actively mode-locked Yb-fiber laser
摘要： This work demonstrates an actively mode-locked all-normal dispersion Yb-fiber ring laser, delivering pulses of few nano-seconds (ns) to sub-ns duration at a 4 MHz repetition rate. Employing a filterless cavity architecture and different, long-length intra-cavity nonlinear fibers; a broadband output spectrum in the 1060–1140 nm wavelength region was obtained. With an increasing pump power, the pulse width reduced along with the appearence of new pulses, resulting into a muti-pulsing output. For a fixed pump power, the number of pulses and the amount of spectral broadening varied for different non-linear fibers. In the multi-pulsing state, the pulses were found to be located seperately in both time and wavelength, where Raman stokes corresponding to individual pulses could also be observed. The maximum output pulse energy achieved in a single pulse state was around 8.7 nJ, which increased to 14.5 nJ in a multi-pulse state. To the best of the authors’ knowledge, this is the first demonstration of a filterless active mode-locked fiber ring laser producing high-repetition rate broadband nano-second pulses in single and multi-pulse states at 1 μm.
关键词： broadband laser,fiber laser,actively mode-locked laser,nano-second pulses
更新于2025-11-28 14:23:57
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L-band tunable and dual-wavelength mode locked fiber laser with NCF-GIMF based SA
摘要： A hybrid structure of no-core fiber and graded-index multimode fiber (NCF-GIMF) is demonstrated, which can be used as both the saturable absorber (SA) and the wavelength selective element. By employing such a device, an L-band wavelength tunable Er-doped mode-locked laser is realized and stable single solitons of ~1.7ps, with continuously tunable wavelengths from 1574 nm to 1601.1 nm, are generated. Moreover, dual-wavelength mode-locked laser operation at 1575.4 nm and 1603 nm is achieved, with pulse duration of 1.2 ps and 1.7 ps, respectively. The proposed device is simple and compact, and represents an effective approach for tunable and dual-wavelength mode-locked fiber laser operation.
关键词： Laser tuning,Optical fiber devices,Laser mode locking,Fiber-graded index multimode fiber,Fiber nonlinear optics
更新于2025-11-28 14:23:57
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Narrow linewidth DBR laser based on high order Bragg grating defined by i-line lithography
摘要： In order to obtain narrow linewidth semiconductor laser around 1564 nm, we design a distributed Bragg reflector (DBR) laser with high-order Bragg gratings (HOBGs) using butterfly encapsulation. The DBR laser is fabricated only by i-line lithography technology with grating period of 4.84 μm, groove width of 1.5 μm and grating length of 72 μm on a strip width of 4 μm. The 1mm-long devices achieved an output power of 9.9 mW and a side mode suppression ratio (SMSR) more than 30 dB without facet coating at an injection current of 80 mA. The lasers showed ultra-narrow Lorentz linewidth of 70 KHz. This paper provides a simple method for large-scale production of narrow linewidth semiconductor lasers.
关键词： narrow linewidth spectrum,Semiconductor laser,high-order grating,distributed Bragg reflector laser
更新于2025-11-28 14:23:57
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Dual-wavelength thulium/holmium-doped fiber laser generation in 2 <i>μ</i> m region with high side-mode suppression ratio
摘要： We demonstrate a dual-wavelength laser with emission in the 2 μm wavelength region using a thulium/holmium co-doped fiber and a non-adiabatic tapered fiber as a comb filter. The configuration employed a backward pumping scheme and dual-wavelength laser was generated at 2023.53 and 2032.82 nm. The side-mode suppression ratio (SMSR) is more than 44 dB with overall good stability performance. The proposed configuration presents a simple yet practical scheme of generating 2 μm dual-wavelength laser with good SMSR. This investigation may offer a more efficient yet eye safe dual-wavelength related applications for end users.
关键词： comb filter,tapered fiber,side-mode suppression ratio,thulium/holmium-doped fiber laser,dual-wavelength laser
更新于2025-11-28 14:23:57
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High-Power Continuous-Wave and Acousto-Optical Q-Switched Ho:(Sc <sub/>0.5</sub> Y <sub/>0.5</sub> ) <sub/>2</sub> SiO <sub/>5</sub> Laser Pumped by Laser Diode
摘要： We experimentally investigate the continuous-wave (cw) and acousto-optical (AO) Q-switched performance of a diode-pumped Ho:(Sc0.5Y0.5)2SiO5 (Ho:SYSO) laser. A fiber-coupled laser diode at 1.91 ??m is employed as the pump source. The cw Ho:SYSO laser produces 13.0 W output power at 2097.9 nm and 56.0% slope efficiency with respect to the absorbed pump power. In the AO Q-switched regime, at a pulse repetition frequency of 5 kHz, the Ho:SYSO laser yields 2.1 mJ pulse energy and 21 ns pulse width, resulting in a calculated peak power of 100 kW. In addition, at the maximum output level, the beam quality factor of the Q-switched Ho:SYSO laser is measured to be about 1.6.
关键词： Laser Diode Pumped,Continuous-Wave,Acousto-Optical Q-Switched,High-Power,Ho:(Sc0.5Y0.5)2SiO5 Laser
更新于2025-11-28 14:23:57
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Mode-locked near-infrared thulium doped fibre laser using evanescent field effect with Bi <sub/>2</sub> O <sub/>3</sub> saturable absorber
摘要： Using the evanescent field effect, a high power passively mode-locked laser with a pulse duration of 1.85 ps and the pulse energy of 13.15 pJ is demonstrated. A Bi2O3 solution is used as a saturable absorber (SA) on a side polished fibre incorporated into a thulium doped fibre laser cavity for operation in the mid-infrared range. The 37.61% SA has a modulation depth and creates a highly stable mode-locked pulse output with a short pulse duration. The calculated net cavity dispersion at central wavelength is ?1.4 ps2, indicating operation is in the anomalous dispersion regime and confirmed by the presence of Kelly’s side-bands observed in the generated optical spectrum. Radio frequency analysis reveals a high signal to noise ratio, making this laser stable for use in telecommunication systems.
关键词： thulium doped fibre laser,evanescent field effect,Bi2O3 saturable absorber
更新于2025-11-28 14:23:57
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Nanotube mode-locked, wavelength and pulsewidth tunable thulium fiber laser
摘要： Mode-locked oscillators with highly tunable output characteristics are desirable for a range of applications. Here, with a custom-made tunable filter, we demonstrate a carbon nanotube (CNT) mode-locked thulium fiber laser with widely tunable wavelength, spectral bandwidth, and pulse duration. The demonstrated laser’s wavelength tuning range reached 300 nm (from 1733 nm to 2033 nm), which is the widest-ever that was reported for rare-earth ion doped fiber oscillators in the near-infrared. At each wavelength, the pulse duration can be regulated by changing the filter’s bandwidth. For example, at ~1902 nm, the pulse duration can be adjusted from 0.9 ps to 6.4 ps (the corresponding output spectral bandwidth from 4.3 nm to 0.6 nm). Furthermore, we experimentally and numerically study the spectral evolution of the mode-locked laser in presence of a tunable filter, a topic that has not been thoroughly investigated for thulium-doped fiber lasers. The detailed dynamical change of the mode-locked spectra is presented and we observed gradual suppression of the Kelly sidebands as the filter’s bandwidth is reduced. Further, using the polarization-maintaiing (PM) cavity ensures that the laser is stable and the output laser’s polarization extinction ratio is measured to exceed 20 dB.
关键词： thulium fiber laser,spectral bandwidth,polarization-maintaiing cavity,Kelly sidebands,tunable wavelength,pulse duration,Mode-locked oscillators,carbon nanotube
更新于2025-11-28 14:23:57
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Self-wavelength-sweeping in a bi-directional thulium-doped fiber ring laser
摘要： We report for the first time the self-wavelength-sweeping phenomenon of a bi-directional thulium-doped fiber ring laser. The laser wavelength can spontaneously sweep in both lasing directions at a rate up to 0.2 nm s?1 over 15 nm sweeping range in the 1.95 μm wavelength region. The sweeping rate can be controlled by simply changing the state of polarization of the laser cavity. The laser can be tuned to generate a periodical wavelength-swept output with microsecond pulses in the time domain. The sweep rate can also be tuned to zero to give a static lasing wavelength.
关键词： self-wavelength-sweeping,thulium-doped fiber ring laser,polarization control,bi-directional
更新于2025-11-28 14:23:57