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Switchable multi-wavelength linearly-polarized lasing oscillations in a figure eight EDF laser based on spatial-mode beating by means of weakly-coupled FMF
摘要: A switchable multi-wavelength figure eight Erbium-doped fiber (EDF) laser with linearly-polarized (LP) beam generation in the C-band region is proposed and experimentally demonstrated. Spatial-mode beating occurs owing to effect of multi-mode interference in the weakly-coupled few-mode fiber (FMF). A bandpass filter of multiple specific wavelengths is created by incorporating a weakly-coupled FMF with a Sagnac fiber loop. The LP modes are generated by cascaded mode-selective couplers (MSCs), which are designed and fabricated by tapering the proposed FMF with single-mode fiber (SMF). Combination of the cascaded MSCs and a simple N × 1 optical switch is employed to switch the LP modes. In experiments, the proposed fiber laser delivers versatile lasing outputs in states of single-, dual-, triple-wavelength oscillations for LP01, LP11 and LP21 modes. We investigate the stabilities for LP01, LP11, LP21 modes in 24-min. Moreover, the mode intensity profiles, optical signal-noise ratios (OSNRs) of lasing output and slope efficiencies are also measured. The proposed fiber laser has promising applications in WDM-MDM optical fiber communication systems, optical fiber sensor systems, optical instruments and spectroscopy.
关键词: Weakly-coupled FMF,Mode selective coupler,Sagnac fiber loop,Erbium-doped fiber laser
更新于2025-09-23 15:19:57
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Q-switched fiber laser based on CdS quantum dots as a saturable absorber
摘要: In this work, a Q-switched fiber laser is demonstrated using quantum dots (QDs) cadmium sulfide (CdS) as a saturable absorber (SA) in an erbium-doped fiber laser (EDFL) system. The QD CdS is synthesized via the microwave hydrothermal assisted method and embedded into polyvinyl alcohol (PVA). The QD CdS/PVA matrix film is sandwiched in between two fiber ferrules by a fiber adapter. The generation of Q-switched fiber laser having a repetition rate, a pulse width, and a peak-to-peak pulse duration of 75.19 kHz, 1.27 μs, and 13.32 μs, respectively. The maximum output power of 3.82 mW and maximum pulse energy of 50.8 nJ are obtained at the maximum pump power of 145.9 mW. The proposed design may add to the alternative material of Q-switched fiber laser generation, which gives a high stability output performance by using quantum dots material as a saturable absorber.
关键词: CdS Quantum Dots,erbium-doped fiber laser,microwave hydrothermal assisted method,saturable absorber,Q-switched fiber laser
更新于2025-09-23 15:19:57
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Fulla??face skin resurfacing using a combination of fractional and full spot ablative 2940??nm erbium laser
摘要: BACKGROUND: Full-field deep ablative laser resurfacing is a popular method for skin rejuvenation due to maximum improvement in a single treatment. However, it is associated with disadvantages such as pain, prolonged erythema, swelling, crusting, infections, pigmentary changes, and scarring. Patients are increasingly seeking less invasive options with comparable effect. AIMS: The aim of this retrospective study was to evaluate the safety and efficacy of full face resurfacing using a combination of full spot and fractional erbium (Er:YAG) laser resurfacing. PATIENTS/METHODS: 109 patients, mostly females over 50 years old, were treated with a two phase protocol: full spot ablation (5 J/cm2, three passes) and fractional ablation (132 J/cm2, 5% coverage, 3 passes). We recorded time to re-epithelization and duration of post-treatment erythema. Any side effects observed at follow-up or reported by the patient were recorded. Patient satisfaction questionnaire and blinded evaluation of pre and post treatment photographs were used to assess efficacy. RESULTS: A single session was performed in 96% of cases. Post-operative re-epithelization lasted on average 6.4±2.9 days. Post-treatment erythema lasted on average 13.8±15.2 days. One patient had hyperpigmentation, one infection, one hypo-pigmentation, and one ulcer. All side effects resolved without complications. According to the blinded assessment of photographs 78% of patients showed improvement. 97% of patients were satisfied with the results of the treatment. CONCLUSIONS: A combination of fractional and full spot ablative Er:YAG laser is a safe and effective option for full face resurfacing.
关键词: patient satisfaction,improvement,fractional,skin resurfacing,laser,erbium
更新于2025-09-23 15:19:57
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Spectroscopic and laser properties of erbium and ytterbium co-doped photo-thermo-refractive glass
摘要: Spectral-luminescent characteristics of erbium ions in photo-thermo-refractive (PTR) glasses doped with different concentrations of ytterbium and erbium oxides were investigated in this work. X-ray diffraction pattern of studied glasses was carried out. Judd-Ofelt parameters of intensity Ωt were obtained and used for deriving emission cross-sections and radiative lifetimes. It was found that the peak emission cross-sections values at a wavelength of 1.53 μm obtained from F-L and McCumber methods are 0.59 × 10?20 cm2 and 0.60 × 10?20 cm2, respectively, which are very similar and compared with those of silicate glasses. A quite high value of quantum yield at the wavelength of 1.53 μm for the sample with 0.1 mol% Er2O3 co-doped with ytterbium oxide has been investigated. Energy transfer efficiency from ytterbium ions to erbium ones was found to be 80% and 86% for erbium- and 1 mol% and 2 mol% Yb2O3-co-doped PTR glass, respectively. Laser properties of 2Yb-01Er PTR glass were carried out. The gain spectrum starts to be positive when the population inversion parameter gets to 0.5. Laser action was demonstrated at room temperature. It was found that the round-trip losses of the Er/Yb-PTR element are 0.28%.
关键词: Ytterbium,DFB laser,PTR glass,Erbium,XRD,Judd-ofelt
更新于2025-09-23 15:19:57
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Gain characteristics of the hybrid slot waveguide amplifiers integrated with NaYF <sub/>4</sub> :Er <sup>3+</sup> NPs-PMMA covalently linked nanocomposites
摘要: Waveguide amplifiers based on slot waveguide have enormous capacity due to their ability to confine light strongly to a narrow slot waveguide. NaYF4:Er3+ nanoparticles-polymeric methyl methacrylate covalently linked nanocomposites were synthesized and filled into the slot. The stability and the Er3+ concentration doped in this novel material were improved. The slot waveguide was designed accurately. The rigorous numerical method, full-vector finite difference method, was used to analyze the modal characteristics and optimize the slot combined with the maximum power confinement in the slot and the minimum effective mode area of the slot. A four-level spectroscopic model pumped at 1480 nm was presented. The rate equations and propagation equations were solved and the gain characteristics of the slot waveguide amplifier were numerically simulated. The primary parameters were optimized. A net gain of 5.78 dB was achieved when the signal power was 0.001 mW at 1530 nm, pump power was 20 mW, Er3+ concentration was 1.3 (cid:1) 1027 m(cid:3)3, and the waveguide length was 1.5 cm.
关键词: NaYF4:Er3+ NPs-PMMA,slot waveguide,erbium-doped polymer waveguide amplifier,full-vector finite difference method,gain characteristics
更新于2025-09-23 15:19:57
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Tungsten tri-oxide (WO <sub/>3</sub> ) film absorber for generating Q-switched pulses in erbium laser
摘要: This paper reports a new type of passive saturable absorber (SA) made of transition metal oxide (TMO) embedded in polyvinyl alcohol (PVA). The Tungsten trioxide (WO3)-PVA SA is placed in an erbium-doped fibre laser cavity to produce Q-switched pulses operating at 1562.82 nm. The pulse laser starts to manifest at the threshold pump power of 40 mW and continues to exist until the maximum pump power of 195 mW. Within that pump power range, its pulse energy, repetition rate and pulse width vary from 98 to 142.85 nJ, 29.86 to 56.7 kHz and 5.032 to 1.85 μs, respectively. The pulse train is stable with a signal to noise ratio of 70 dB. This is the first demonstration of a Q-switched laser using such a SA.
关键词: saturable absorber,WO3,Q-switched,Erbium-doped fibre laser
更新于2025-09-23 15:19:57
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Ghost Spectroscopy with Classical Correlated Amplified Spontaneous Emission Photons Emitted by An Erbium-Doped Fiber Amplifier
摘要: We demonstrate wavelength-wavelength correlations of classical broad-band amplified spontaneous emission (ASE) photons emitted by an erbium-doped fiber amplifier (EDFA) in a wavelength regime around 1530 nm. We then apply these classical correlated photons in the framework of a real-world ghost spectroscopy experiment at a wavelength of 1533 nm to acetylene (C2H2) reproducing the characteristic absorption features of the C-H stretch and rotational bands. This proof-of-principle experiment confirms the generalization of an ASE source concept offering an attractive light source for classical ghost spectroscopy. It is expected that this will enable further disseminating ghost modality schemes by exploiting classical correlated photons towards applications in chemistry, physics and engineering.
关键词: spectral correlations,quantum optics,coherence,correlated photons,erbium-doped fiber amplifier,photon correlation modalities,ghost imaging,amplified spontaneous emission (ASE),spectroscopy,ghost spectroscopy,ghost modalities
更新于2025-09-19 17:15:36
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Synthesis, structure and optical properties of Erbium-doped Lithium Barium Phosphate
摘要: Li2BaP2O7 activated with Er3+ ions was prepared by the classic ceramic method and characterized by X-ray diffraction technique, IR, Raman and photoluminescence (PL) spectroscopies. The Li2BaP2O7: Er phosphors exhibited a monoclinic single phase structure with C2/c space group. A green and red emission lines dominate the spectrum upon excitation at 400 nm. The CIE-coordinate (x = 0.308, y = 0.512) were found in green light. Free ion parameters of the Er3+ ions in Li2BaP2O7 and the Judd–Ofelt parameters were calculated and they were used to explore the radiative parameters such as transition probability (AT), and branching ratios (β) related to the Er3+ emission transitions. The calculated 4S3/2 radiative life time around 0.198 ms is compared with the experimental value. The calculated quantum efficiency is about 42 %. Li2BaP2O7: Er can be considered as a novel green phosphor.
关键词: Erbium,green phosphor,Judd-Ofelt theory,optical spectroscopy
更新于2025-09-19 17:15:36
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[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - Theoretical Analysis and Design of Longitudinal Leaky SAW Device Consisting of ScA1N Film / Piezoelectric Single Crystal Substrate
摘要: Theoretical Analysis and Design of Longitudinally Pumped Erbium-Doped Fiber Amplifiers for High-Power Operation
关键词: Fiber optics,Optical amplification,Erbium-doped fiber amplifier,Longitudinal pumping,High-power operation
更新于2025-09-19 17:15:36
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Application of Judd-Ofelt Theory Upon Chlofluorophosphate Glass Doped with Erbium
摘要: A series of erbium doped glasses chlorofluorophosphates were prepared and characterized. The absorption spectra were analyzed to determine the Judd-Ofelt parameters. The optical performance of these doped glasses suggesting the relevance of these glasses for optical fiber/ wave guide lasers and optical amplifiers.
关键词: and optical amplifier,rare earth,Judd-Ofelt parameters,glass doped,laser,erbium
更新于2025-09-19 17:15:36