Concentration Of Ytterbium Ions Research Articles

Narrow-Linewidth Single-Frequency Ytterbium Laser Based on a New Composite Yb3+-Doped Fiber

Fiber single-frequency lasers are currently being actively developed, primarily due to the growing number of applications that require compact and reliable narrow-band sources. However, the most developed single-frequency fiber lasers based on phosphate fibers have the disadvantages of low mechanical strength of both the phosphate fibers themselves and their splices. In this paper we demonstrate a single-frequency laser based on a new composite Yb3+-doped active fiber. The core of this fiber is made of phosphate glass with a high concentration of ytterbium ions and its cladding is made of standard silica glass. This structure ensures a higher splicing strength of the fiber compared to the phosphate fibers and provides high resistance to atmospheric moisture. Despite the multimode structure of this fiber, we achieved stable single-frequency lasing with an average power of 10 mW and a spectral contrast of more than 60 dB in the scheme with a short (1.1 cm) cavity formed by two fiber Bragg gratings. We believe that further optimization of this fiber will make it possible to create powerful and reliable single-frequency lasers in the one-micron wavelength range.

Ytterbium-doped chloride photo-thermo-refractive glass: spectral, luminescent, and gain properties

We developed a new chloride photo-thermo-refractive glass doped with ytterbium ions. The dependence of optical and spectral-luminescent characteristics on ytterbium concentration has been studied. Concentration dependence of excited state decay time has been analyzed taking into account the self-trapping and self-quenching mechanisms. The optimum concentration of ytterbium ions in chloride photo-thermo-refractive glass has been determined. Other important spectroscopic parameters such as absorption and emission cross-sections, radiative lifetimes, pump saturation, and minimum pump intensities have been obtained using absorption and emission measurements and theoretical approaches such as Fuchtbauer-Landenburg and McCumber theories. The evolution of the gain cross-section spectrum as a function of a population inversion parameter has been performed. Results of this study show that the ytterbium-doped chloride photo-thermo-refractive glass demonstrates good spectroscopic and luminescent properties for laser and gain application.

Optimization of an EYDWA Amplifier Parameters for a Gigabit Passive Optical Network (GPON)

Abstract The purpose of this study is to evaluate the impact of the location of the Er3+/Yb3+optical amplifier (EYDWA) in passive optical access network downstream (as a post-amplifier or booster, in the middle) and upstream transmission . This can give us an extended connection and a huge distribution ratio for a beneficial implementation of the optical fiber. The transmission quality was compared on the location of the amplifier as well as the length of the link. According to the results obtained by system simulation one noted that there is a clear improvement of the system performance by the effect of the amplifier (EYDWA). One could obtain a distance of more than 200 km for GPON. Moreover by varying the opto-geometric parameters such as concentration of Ytterbium ions and the length of the guide allowed us to improve the quality factor and binary error rate.

All-fiber heavily ytterbium-doped, passively mode-locked laser with the 456 MHz repetition rate.

In this Letter, we report on, to the best of our knowledge, the first demonstration of ultrashort pulses generation with an all-fiber laser with the repetition rate of up to 456MHz, without the use of additional nonlinear optical elements. It was possible to obtain this repetition rate thanks to the use of a specially manufactured heavily doped ytterbium fiber. The generation dynamics of the laser assembled according to the classical Fabry-Perot scheme with two fiber Bragg gratings was investigated. The formation of ultrashort pulses as a result of passive mode-locking (ML) is presented. Passive ML is attributed to the absorption saturation, while the role of the saturable absorber in the active optical fiber with a high ytterbium ion concentration plays itself.

Spectroluminescent properties of ytterbium-activated fluorophosphate glasses

In this work, we studied the effect of the concentration of ytterbium ions on the spectroluminescent properties and laser parameters of fluorophosphate glasses of the Ba(PO3)2–MgCaSrBaAl2F14 system. It was shown that the absorption peak corresponds to λp=974 nm, and the stimulated emission peak is located at λ0=1002 nm. It was established that the position of these peaks does not change with an increase in the ytterbium content. The highest values of the stimulated emission cross-section σemi=0.562×10−20 cm2 and the luminescence lifetime τexp=2.1 ms correspond to the YbF3 concentration of 0.5 mol. %. The quantum yield Q for the YbF3 concentration of 0.5 mol. % is 91.6%. The presented glasses have a long luminescence lifetime, and the calculations show the possibility of obtaining large values of gain G.

Optimised preparation of silver inorganic antibacterial material containing ytterbium using response surface methodology

In this work, a silver inorganic antibacterial containing ytterbium was synthesised using response surface methodology. Statistical analysis of the results showed that the bulk density of the Ag-Yb antibacterial white carbon black was characterised by the reaction time, reaction temperature and ytterbium ion concentration. The optimised reaction conditions were as follows: reaction time was 75 min, reaction temperature was 85°C and ytterbium ion concentration was 0·01 mol L−1. The structure and property of the inorganic antibacterial material were characterised by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy and antibacterial experiments (Escherichia coli as experimental bacteria). Results showed that the bacteriostatic rate of Ag-Yb antibacterial white carbon black was >90%.

Design and refinement of rare earth doped multicore fiber lasers

A novel multicore ytterbium doped fiber laser is designed, with the target of maximizing both the effective mode area and the beam quality, by means of a complete home-made computer code. It can be employed to construct high power and Quasi-Gaussian beam lasers. The novel laser configuration exploits a single mode multicore fiber and does not need Talbot cavity or other in-phase mode selection mechanisms. This is an innovative solution, because to the best of our knowledge, for the first time, we have designed a truly single-mode multicore fiber laser. For comparison we have optimized two other laser configurations which are well known in literature, both employing a multimode multicore fiber and a Talbot cavity as a feedback for the in-phase supermode selection. All three multicore fibers, constituted by the same glass, are doped with the same ytterbium ion concentration and pumped with the same input power. Multimodal fiber lasers exhibit lower beam quality, i.e. a higher beam quality factor M2, with respect to the single mode one, even if suitable Talbot cavities are designed, but they are very competitive when a more compact laser cavity is required for the same output power. The novel single mode nineteen core laser exhibits a simulated effective mode area Aeff=703μm2 and a beam quality factor M2=1.05, showing better characteristics than the other two lasers.

Structural and Chemical Characterization of Yb2O3-ZrO2 System by HAADF-STEM and HRTEM

ZrO2:Yb3+ nanocrystalline phosphors with high concentrations of ytterbium ions were prepared using the sol-gel method. X-ray diffraction, high-angle annular-dark-field scanning transmission electron microscopy (HAADF-STEM), energy dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy (HRTEM) were used to characterize the nanocrystalline phosphors annealed at 1000 degrees C. Unit-cell distortion and changes in the crystalline structure of the monoclinic zirconia to tetragonal zirconia, and subsequently cubic zirconia, were observed with increased Yb concentration. Yb ions were randomly distributed into the lattice of the crystalline structure. No segregation of Yb2O3 phase was observed. The substitution of Zr atoms by Yb atoms on different crystalline phases was confirmed by the experimental results and theoretical simulations of HRTEM and HAADF-STEM.

Gain spectra in ytterbium-erbium metaphosphate glasses for microlasers

Direct measurements of the gain/loss spectra for the principal transition of the erbium ion (1.5μm) in ytterbium-erbium phosphate glasses as a function of the concentration of ytterbium ions and the laser pump power have been carried out. The ytterbium concentration was varied from zero to the limiting value of 52.4×1020cm−3. It is shown that increasing the ytterbium concentration, beginning with NYb=20.9×1020cm−3, results in a reduction of the gain threshold. On glass with the limiting ytterbium concentration (ytterbium metaphosphate), population inversion is achieved at low pump powers of 35mW. The largest gain of 0.1cm−1 is obtained on a sample 0.5mm thick with ytterbium concentration 41.7×1020cm−3 and erbium concentration 0.29×1020cm−3 with an absorbed pump power of 210mW.

How the ytterbium concentration affects the population inversion of erbium in phosphate laser glasses

The population of the metastable level of erbium in ytterbium-erbium phosphate glasses has been measured as a function of the concentration of ytterbium ions and the power of the laser pumping. The ytterbium concentration was varied from 0 to a limiting value of 52.4×1020cm−3. It is established that increasing the concentration of ytterbium ions causes the population inversion of erbium to increase.

Glasses for praseodymium laser amplifiers sensitised with neodymium and ytterbium

A new sensitised scheme for optical pumping of praseodymium amplifiers, operating in the spectral range 1.3 μm, was proposed and investigated. The amplifiers were pumped in the absorption band of neodymium ions. In fluoride glasses with a high ytterbium ion concentration, the excitation energy was efficiently nonradiatively transferred along the Nd3+—Yb3+—Pr3+ chain.

The anomalous ferrimagnetic resonance properties of ytterbium-doped yttrium iron garnet

In single-crystal specimens of yttrium iron garnet doped with small amounts of ytterbium the ferrimagnetic resonance linewidths and the fields for resonance show anomalous behaviour in certain crystallographic directions at low temperatures. This paper presents some observations of this anomalous behaviour at 16·8 and 9·3 Gc/s as functions of temperature (1·5-25°K), concentration of ytterbium ions (1·, 5·1 and 10·2%) and direction of the applied magnetic field. The loci of the anomaly are deduced to be the (111) crystallographic planes, and some effects of thermal annealing are described. Some thoughts on the possible origin of the anomaly are also presented, from which it is found that many, though not all, features of the anomalous behaviour can be described by transverse resonance relaxation (with a relaxation time of approximately 5 × 10-11 sec) occurring at a near-crossing of the low-lying energy levels (minimum energy separation about 0·8 cm-1) of a small minority of Yb ions occupying `defect' sites.