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Intrinsic Defect-Assisted UV-Visible Energy Conversion in Gd <sub/>2</sub> O <sub/>3</sub> :Er Nanoparticles
摘要： The correlations between defectiveness and optical properties of Er-doped Gd2O3 nanoparticles coupled into cubic and monoclinic crystal structures were studied employing XPS and PL spectroscopies. The main focus of this research is paid to the cubic Gd2O3 phase, which is more suitable for light-emitting purposes. It is shown that oxygen-related point defects are the precursors for the formation of cationic irregulars – “defective” Gd3+ ions with local energy levels in the energy band gap of Gd2O3. Energy transfer from Gd3+ intrinsic defects to Er3+ dopants provides an additional channel for UV–visible radiation conversion. These Er3+ ions have bimodal distribution due to the non-equivalent lattice sites of “defective” Gd3+ ions. An increase of Er3+ concentration leads to the giant phonon softening effect, which opens up a new prospective way to enhance energy conversion efficiency.
关键词： UV conversion,photoluminescence,gadolinium oxide,erbium,defects
更新于2025-09-19 17:15:36
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Re: Erbium:YAG Laser Treatment of Female Stress Urinary Incontinence: Midterm Data
摘要： The role of intravaginal laser therapy for the treatment of women with a clinical and urodynamic diagnosis of stress urinary incontinence (SUI) or mixed urinary incontinence was the focus of the recent study by Kuszka and colleagues. To evaluate subjective and objective outcomes of Er:YAG therapy with SMOOTH mode technology, the authors enrolled 59 women, of whom 32 had grade I (54%), 16 had grade II (27%), and 11 had grade III SUI (19%). Using validated questionnaires (ICIQ-UI SF, PISQ 12) and 1-h pad weight at baseline, after two, four, and five laser sessions, and at 6-mo and 2-yr follow-up, the authors found that intravaginal laser therapy led to cure/improvement for grades I and II but not for severe SUI. At least three laser sessions at intervals of 1 mo are required to obtain better results from laser therapy. Outcomes at the 6-mo and 2-yr follow-up visits were similar, indicating that laser treatment is suitable and does not need to be repeated within 2 yr.
关键词： Female Stress,Urinary Incontinence,Midterm Data,Treatment,Erbium:YAG Laser
更新于2025-09-19 17:13:59
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MAX phase based saturable absorber for mode-locked erbium-doped fiber laser
摘要： We presented an ultrashort pulse generation in an erbium-doped fiber laser cavity using MAX-PVA as a mode-locker. A thin film of SA was prepared by mixing PVA with Ti3AlC2 as a saturable absorber inside the laser cavity. The optical nonlinearity was also demonstrated, revealing a saturable absorption of 2%, a non-saturable absorption of 58.2%, and a saturation intensity of 1.63 MW/cm2. The excellencies of MAX-PVA was proven as it initiates ultrafast laser with a duration of 3.68 ps corresponds to a repetition rate of 1.887 MHz. The ease of preparation, together with its superior optical, physical, thermal, and mechanical properties, makes it a favorable SA for pulse generation in an all-fiberized laser cavity.
关键词： Ultrashort pulse,MAX phase,Erbium-doped fiber laser,Saturable absorber,Mode-locked
更新于2025-09-19 17:13:59
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Wavelength-switchable erbium-doped fiber laser incorporating fiber Bragg grating array fabricated by infrared femtosecond laser inscription
摘要： Wavelength-switchable fiber laser systems have many potential applications. Herein, the use of an erbium-doped fiber laser based on parallel fiber Bragg gratings (FBGs) (ASE: amplified spontaneous emission; BRM: broadband reflection mirror; CCD: charged-coupled device; EDFL: erbium-doped fiber laser; FBG: fiber Bragg gratings; IR: infrared; MZI: Mach–Zehnder interferometer; OSA: optical spectrum analyzer; OC: output coupler; PC: polarization controller; SNR: signal-to-noise ratios; 3D: three-dimensional; wavelength division multiplexing (WDM)) is proposed to achieve C + L band triple-wavelength-switchable laser output at approximately 1.5 μm. In the proposed system configuration, three parallel FBGs with different resonant wavelengths were fabricated using an 800 nm femtosecond pulsed laser. The proposed fiber laser incorporates first-order FBGs with the periods of 538, 542, and 547 nm. The femtosecond laser was propagated through polyimide coating and cladding and was focused onto the fiber core by a 63× oil lens, while FBGs were inscribed with the use of a point-by-point method to generate resonant wavelengths at 1555.3, 1569.2, and 1583.1 nm. When the FBGs were used as wavelength selectors, a lasing threshold of 85 mW was obtained, and switchable lasing with stable single- and dual-wavelength outputs was achieved based on the adjustment of a polarization controller. Concerning the switchable single-wavelength lasing, the signal-to-noise ratio was greater than 37.23 dB, and the 3 dB linewidth was less than 0.09 nm. The respective power fluctuation measurements were less than 0.22 and 0.68 dB for the single- and dual-wavelength lasers at 26 °C over a scan time of 30 min.
关键词： Erbium-doped fiber laser,Femtosecond laser,Point-by-point wavelength generation method,Fiber Bragg grating
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 14th Malaysia International Conference on Communication (MICC) - Selangor, Malaysia (2019.12.2-2019.12.4)] 2019 IEEE 14th Malaysia International Conference on Communication (MICC) - Investigation of Q-switched and Mode-Locked Erbium-Doped Fiber Laser Using Graphene oxide-Saturable Absorber
摘要： This paper experimentally investigates a simple configuration of an erbium-doped fiber laser (EDFL) cavity to generate mode-locked and Q-switched pulses utilize graphene oxide as saturable absorber (GO-SA). The GO-SA chip is a chip placed as a sandwich between two fiber ferrules and incorporates a ring laser cavity to generate a pulse train. Results indicate that the cavity of passive Q-switching EDFL is capable of providing pulses at 1532nm with a pulse width within a range of 5.32μs to 2.6μs, a repetition rate of 59.5kHz to 71.74kHz, a pulse energy of 364.64nJ to 668.95nJ, and an output power ranging from 0.062mW to 0.136mW, when the configuration is pumped by a 980nm laser diode, the power of which gradually increases from 21.7mW to 47.9mW. The output of the GO-SA needs to be connected to 200m of a single-mode fiber (SMF) to generate mode-locked pulses at 1559nm when the pump power is 157.6mW. As a result, an output power of 1.29mW is delivered with a repetition rate of 1.002MHz.
关键词： Erbium-Doped Fiber Laser,Q-switched,Saturable Absorber,Mode-Locked,Graphene oxide
更新于2025-09-19 17:13:59
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On the Analysis and Comparison of Decoupled Modal Gain Equalization Systems for Four-Mode (4a??M)-EDFAs
摘要： Space-Division Multiplexing (SDM) has gained considerable interest as a promising means to increase transmission capacity per fiber. For proper use of this technology, optical components of transmission line including Erbium-Doped Fiber Amplifiers (EDFAs) need to be re-examined. In this work we analyze modal gain equalization systems obtained from extended Giles model for 4M-EDFA. We introduced a simpler method of calculation of two radial overlap factors extracted from the model using standard B-V curve thus proposing two decoupled systems for Modal Gain Equalization. In Decoupled Mode-Specific Pump Combination (MSPC) system so obtained, Maximum Differential Modal Gain (DMG) was reduced to 1.55 dB with mean gain of about 28.72 dB. For Modified Erbium Doped Profile (MEDP) system we obtained an optimum Multi-Well Profile. The maximum DMG here showed further reduction to 1.3254 dB with mean gain of about 24.24 dB. Further we report investigation on evolution of ASE for 4M-EDFA for the first time with new performance metric namely ASE ratio to indicate the deviation of noise between four modes. The ASE levels reached in MEDP are smaller than MSPC system thus enabling reduction in Noise Figure. Simulation results and comparison indicated that in MEDP, DMG is more sensitive to variation in length, concentration and wavelength. Our designed MEDP and MPC system as well as simple 4M-EDFA system gave good pre-amplification performance for data rates smaller than 15 Gb/s.
关键词： Doping profiles,Erbium Doped Profile,Overlap Factors,Modal Gain Equalization,ASE Ratio,SDM Amplifiers
更新于2025-09-19 17:13:59
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Comparison of fractional neodymium-doped yttrium aluminum garnet (Nd:YAG) 1064-nm picosecond laser and fractional 1550-nm erbium fiber laser in facial acne scar treatment
摘要： To compare the safety and efficacy of fractional neodymium-doped yttrium aluminum garnet (Nd:YAG) 1064-nm picosecond laser and fractional 1550-nm erbium fiber laser in acne scar treatment and to assess the adverse effects and complications of the two devices. Thirty patients with cosmetically similar acne scars on both sides of the faces were enrolled and treated four times at 4-week intervals. Each side of the face was treated with either fractional 1064-nm Nd:YAG picosecond laser or fractional 1550-nm erbium fiber laser. Efficacy was evaluated using digital photography taken at baseline and 5 months by a blinded dermatologist using the ECCA grading scale (échelle d’évaluation clinique des cicatrices d’acné). Patient overall satisfaction and self-rated improvement scores were recorded at baseline and 5 months. Adverse effects were recorded at every visit. Twenty-seven patients completed the study. Both devices demonstrated significant median ECCA score improvement from baseline (P < 0.001). However, there was no significant difference between the two in terms of median ECCA score improvement, patients’ perception of scar improvement, and overall satisfaction. Considering the adverse effects, more pinpoint bleeding was significantly observed with the picosecond laser (P = 0.002), whereas more pain was noted with the erbium laser (P < 0.001). Both fractional 1064-nm Nd:YAG picosecond laser and fractional 1550-nm erbium fiber laser are safe and effective in the treatment of acne scars. Costs should be taken into consideration when deciding on which device to use to maximize treatment outcomes.
关键词： Erbium fiber laser,Acne scar,Picosecond laser,Acne scar treatment,Fractional laser
更新于2025-09-19 17:13:59
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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) - All-fiber Passively Mode-locked Femtosecond Laser Based on a Femtosecond Laser Inscribed 45° Tilted Fiber Grating
摘要： A femtosecond erbium-doped fiber laser using a novel 45° tilted fiber grating fabricated by direct femtosecond laser inscription is experimentally demonstrated. The laser generates stable short pulses with pulse width of 752 fs at 1562 nm. The experimental results demonstrate that mode locking is successfully achieved with pulse duration of 752 fs and pulse energy of 2.23 nJ. In particular, this kind of 45° TFG is capable of maintaining the strength and physical integrity of the fiber because it is not necessary to remove the fiber coating during inscription process.
关键词： nonlinear polarization rotation,Erbium-doped fiber laser,tilted fiber grating
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE Colombian Conference on Communications and Computing (COLCOM) - Barranquilla, Colombia (2019.6.5-2019.6.7)] 2019 IEEE Colombian Conference on Communications and Computing (COLCOM) - Ultrashort Pulse Generation in EDFL Cavities using Graphene as Saturable Absorber for applications in optical communications systems
摘要： Graphene and 2D materials are being used in the design of light sources due to their wide absorption spectrum, ultrafast recovery time and high modulation depth. In this work, we present a experimental design of an modelocking Erbium-Doped-Fiber-Laser (EDFL) that uses graphene deposited onto D-shaped optical fiber, acting as a saturable absorber, in order to generate ultra-short pulses in an important region for optical communications: 1558.5 nm. To best of our knowledge, this is the first ultrashort pulses laser designed an experimentally validated in Colombia. The results shows a pulsed laser with a repetition rate of 33.3 MHz and a spectral width of 10 nm.
关键词： Saturable absorber,Graphene,Erbium-doped-fiber-laser,Mode-locking,D-shaped Optical fiber,Ultrashort pulses
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Broadband Dual-Comb Spectroscopy of Methane with a Free-Running Erbium Chip Laser
摘要： Dual-comb interferometry enables the identification of a gas through the measure of its unique spectral signature with high resolution and fast acquisition. It has been used here to study the spectroscopic properties of an important greenhouse gas: methane. The environmental influence of methane, as well as its economic impact, have proven the need to study its spectroscopic signature with a high level of accuracy. We report a free-running dual-comb spectrometer which has the potential to fulfil the need for high accuracy portable methane monitoring. The C-band spectrometer reported is now broadened from 1400 nm to 1700nm using fiber amplifiers and highly nonlinear fiber (HNLF). The dual-comb laser originates from two passively mode-locked waveguide lasers integrated into a single Er-doped ZBLAN chip. Free-running combs with high mutual coherence are produced with a repetition rate of 968 MHz and a repetition rate difference of 27 kHz. No phase locks, optical references or self-referencing are required. Through the use of a SESAM mode-locking configuration, the lasers self-start and occupy a volume less than 1.2 L, making it an efficient and compact design.
关键词： methane,free-running laser,dual-comb spectroscopy,spectrometer,erbium chip laser
更新于2025-09-16 10:30:52