Tellurite Glass Fiber Research Articles

Polarization splitter based on dual-core photonic crystal fiber with tellurite glass

A polarization splitter based on dual-core photonic crystal fiber (PCF) with tellurite glass was proposed. The birefringence of the splitter was improved by introducing elliptical air holes. The full vector finite element method is used to analyze the impacts of structural parameters on the coupling length. The results show that the elliptical size is reasonably changed, the extinction ratio can reach 107.21 dB at the wavelength of 1.55 μm, the length of the splitter is 89.05 μm, and the bandwidth is 150 nm when the extinction ratio is more than 20 dB. Besides, we also compare the characteristics of tellurite glass and silica glass photonic crystal fiber polarization beam splitters with the same structural parameters.

Magnetically sensitive nanodiamond-doped tellurite glass fibers

Traditional optical fibers are insensitive to magnetic fields, however many applications would benefit from fiber-based magnetometry devices. In this work, we demonstrate a magnetically sensitive optical fiber by doping nanodiamonds containing nitrogen vacancy centers into tellurite glass fibers. The fabrication process provides a robust and isolated sensing platform as the magnetic sensors are fixed in the tellurite glass matrix. Using optically detected magnetic resonance from the doped nanodiamonds, we demonstrate detection of local magnetic fields via side excitation and longitudinal collection. This is a first step towards intrinsically magneto-sensitive fiber devices with future applications in medical magneto-endoscopy and remote mineral exploration sensing.

Development of Er^3+-doped high-purity tellurite glass fibers for gain-switched laser operation at 27 μm

We present low-loss tungstate-tellurite fibers doped with Er3+ for laser operation near 2.7 μm. Two “ultra-dry” preforms with cores of TeO2-WO3-La2O3-Bi2O3 glasses doped with 0.4 and 4 mol% of Er2O3 and undoped TeO2-WO3-La2O3 claddings were produced. High-quality multimode fibers were fabricated and characterized. Photoluminescence spectra of about 2.7 μm (4I11/2 → 4I13/2 transition) and about 1.6 μm (4I13/2 → 4I15/2 transition) were measured under excitation by diode pumping at 975 nm (4I15/2 → 4I11/2 transition). The production test and the theoretical investigation of gain-switched laser generation showed potential applicability of the designed samples in the spectral range of interest. Prospective application of single-mode fibers based on the developed glass preforms was also simulated. A feasibility of pulse train generation was demonstrated even for a rough choice of parameters, which is very encouraging for experimental implementation.

Preparation of Ho3+/Tm3+ Co-doped Lanthanum Tungsten Germanium Tellurite Glass Fiber and Its Laser Performance for 2.0\u2009\u03bcm

Ho3+/Tm3+ co-doped 50TeO2-25GeO2-3WO3-5La2O3-3Nb2O5-5Li2O-9BaF2 glass fiber is prepared with the rod-tube drawing method of 15 μm core diameter and 125 μm inner cladding diameter applied in the 2.0 μm-infrared laser. The 2.0 μm luminescence properties of the core glass are researched and the fluorescence intensity variation for different Tm3+ doping concentration is systematically analyzed. The results show that the 2.0 μm luminescence of Ho3+ is greatly influenced by the doping concentration ratio of Ho3+ to Tm3+ and that the maximum fluorescence intensity of the core glass can be obtained and its emission cross section can reach 0.933 × 10−21 cm2 when the sensitized proportion of holmium to thulium is 0.3 to 0.7 (mol%). Simultaneously, the maximum phonon energy of the core glass sample is 753 cm−1, which is significantly lower than that of silicate, gallate and germanate glass and the smaller matrix phonon energy can be conductive to the increase 2.0 μm-band emission intensity. The continuous laser with the maximum laser output power of 0.993 W and 2051 nm -wavelength of 31.9%-slope efficiency is output within the 0.5 m glass fiber and the experiment adopts 1560 nm erbium-doped fiber laser(EDFL) as the pump source and the self-built all-fiber laser. Therefore, the glass fiber has excellent laser characteristics and it is suitable for the 2.0 μm-band laser.

Multi-watt mid-infrared supercontinuum generated from a dehydrated large-core tellurite glass fiber

We report for the first time multi-watt mid-infrared supercontinuum (SC) output from a dehydrated tellurite step-index fiber. The tellurite glass preform is melted in a dry-atmosphere filled glovebox and the water impurity in the glass has been reduced to 1ppm level. The fiber has a large core diameter of 12 µm and a numerical aperture (NA) of 0.21. Using the amplified Raman-shifted soliton pulses from a 1.55 µm erbium-doped fiber laser as the pump, a broadband 2-3 µm supercontinuum with a 3dB bandwidth of 985 nm has been generated from an 80cm-long dehydrated tellurite glass fiber. The power spectral density of the SC is above 3.5 dBm/nm in the whole range of 2-3 µm. The net output power of the supercontinuum from the tellurite fiber is measured to be 2.1 W. To the best of our knowledge, this is the highest average power of mid-IR SC generated from a tellurite fiber. The spectral density of above 3 dBm/nm is also one of the highest spectral densities of a SC achieved in 2.5-3 μm range from an oxide glass fiber.

20 μm Nd^3+/Ho^3+-doped tungsten tellurite fiber laser

Tellurite glass has emerged as a promising ~2.0 μm laser material owing to its excellent features of supporting efficient mid-infrared emission and easy fiber-pulling over the commonly investigated glasses. In this paper, we report an efficient ~2.0 μm laser output from a new-type of Nd3+/Ho3+ co-doped tungsten tellurite fiber laser by using an ultra-short length fiber of 5 cm upon a 795 nm laser diode. The tellurite fibers have been fabricated by a suction technique with the core and cladding diameters of 32 and 125 μm, respectively. The propagation loss of the fiber is measured to be 4.44 dB/m at 1310 nm by using the cutback method. The large energy transfer coefficient from Nd3+ to Ho3+ (3.8 × 10−40 cm6·s–1) and high gain coefficient of Ho3+: 5I7 → 5I8 transition (1.2 cm–1) have confirmed the success of using Nd3+ as sensitizer to realize the ~2.0 μm laser emission of Ho3+. The maximum output power of the laser is obtained to be 12 mW at a center wavelength of 2052 nm with a slope efficiency of 11.2%. The laser threshold is as low as 38 mW, which is around one order of magnitude lower than the previously reported Tm3+/Yb3+ doped tellurite fiber lasers with the similar pump scheme and fiber geometry. The results indicate that the Nd3+/Ho3+ co-doped tungsten tellurite glass fiber laser is a promising laser medium candidate for achieving the ultra-compact and efficient ~2.0 μm laser.

Toward a mid-infrared femtosecond laser system with suspended-core tungstate-tellurite glass fibers.

A simple design of a fiber laser system for generating high-quality pulses with a duration of order 100 fs with ultrabroad wavelength tunability in the 2-5 μm range is discussed. This design incorporates conventional fs near-IR lasers and specially developed tungstate-tellurite fibers with two zero-dispersion wavelengths (ZDW) and relies on nonlinear wavelength conversion via either soliton self-frequency shift (SSFS) or red-shifted dispersive wave (DW) generation. The fiber parameters needed for such optical conversion have been scanned numerically and showed a possibility of SSFS beyond 4 μm and of DW generation beyond 5 μm. We have also studied and prepared tungstate-tellurite glasses and preforms that are highly stable against crystallization, exhibit extremely low level of hydroxyl groups absorption, and from which the suspended-core two-ZDW fibers can be manufactured.

Spectroscopic and structural characterization of barium tellurite glass fibers for mid-infrared ultra-broad tunable fiber lasers

To meet the growing demand for mid-infrared tunable fiber lasers, the spectroscopic and structural properties of Tm3+/Ho3+ co-doped barium tellurite glass fibers are systematically evaluated by absorption, Raman, and photoluminescence spectra measurements. The density, molar volume, refractive index, and glass transition temperature are assessed in detail to fully understand their basic physical and thermal properties. Benefitting from the multiple structural sites in a barium tellurite glass system, the maximum doping concentration of Tm2O3 reaches up to 6.0 wt.% without inducing any crystallization or phase separation. Such a high ion concentration is conducive to reducing the fiber length and obtaining an efficient laser output. Furthermore, an intense ~2.0 μm ultra-broad emission with a full width at half maximum (FWHM) of 382 nm is achieved in the Tm3+/Ho3+ co-doped sample upon excitation at 808 nm by properly adjusting Tm3+ concentration and fiber length. The larger emission cross-sections and higher gain coefficients along with excellent thermal stability indicate that this barium tellurite glass could be an attractive gain medium for mid-infrared ultra-broad tunable fiber lasers.

Spectroscopic and laser properties of Ho3+ doped lanthanum‐tungsten‐tellurite glass and fiber

The spectroscopic properties of 2-μm emission in Ho3+-doped lanthanum–tungsten–tellurite glasses with different Ho2O3 concentrations were investigated. The strongest emission was observed in a glass sample doped with 0.5mol% Ho2O3, with a fluorescence lifetime of 3.16ms and a emission cross section of 6.97×10−21cm2 at 2040nm. For this composition, no obvious changes in the emission properties and fluorescence lifetime were observed at temperatures of 295–350K. Using this 60TeO2–30WO3–9.5La2O3–0.5Ho2O3 glass as a core material, Ho3+-doped double cladding fiber with a core diameter of 14μm and a numerical aperture of 0.12 was developed. A maximum laser output power of 34mW at 2040nm was achieved with a 9-cm-long Ho3+-doped tellurite glass fiber. To the best of our knowledge, this study presents the first report on the 2-μm laser output from a Ho3+-doped tellurite oxide glass fiber resonantly pumped by a 1.94μm Tm-fiber laser.

Enhancement of fluorescence emission and signal gain at 1.53 µm in Er3+/Ce3+ co-doped tellurite glass fiber

Er3+/Ce3+ co-doped tellurite glasses with composition of TeO2-GeO2-Li2O-Nb2O5 were prepared using conventional melt-quenching technique for potential applications in Er3+-doped fiber amplifier (EDFA). The absorption spectra, up-conversion spectra and 1.53 µm band fluorescence spectra of glass samples were measured. It is shown that the 1.53 µm band fluorescence emission intensity of Er3+-doped tellurite glass fiber is improved obviously with the introduction of an appropriate amount of Ce3+, which is attributed to the energy transfer (ET) from Er3+ to Ce3+. Meanwhile, the 1.53 µm band optical signal amplification is simulated based on the rate and power propagation equations, and an increment in signal gain of about 2.4 dB at 1 532 nm in the Er3+/Ce3+ co-doped tellurite glass fiber is found. The maximum signal gain reaches 29.3 dB on a 50 cm-long fiber pumped at 980 nm with power of 100 mW. The results indicate that the prepared Er3+/Ce3+ co-doped tellurite glass is a good gain medium applied for 1.53 µm broadband and high-gain EDFA.

Enhanced 1.53 μm radiative transition in Er3+/Ce3+ co-doped tellurite glass modified by B2O3 oxide

Er3+/Ce3+ co-doped and B2O3 modified tellurite glasses with initial composition of TeO2–GeO2–Li2O–Nb2O5 were prepared using melt-quenching technique for potential applications in Er3+-doped fiber amplifiers (EDFAs) and lasers. The absorption spectra, fluorescence spectra, up-conversion spectra, Raman spectra and differential scanning calorimeter (DSC) curves of glass samples were measured to evaluate the effect of B2O3 modification on the 1.53μm band spectroscopic properties of Er3+, structural nature and thermal stability of glass hosts. It was shown that the introduction of an appropriate amount of B2O3 oxide can further improve the 1.53μm band fluorescence emission through an enhanced phonon-assisted energy transfer (ET) from Er3+ to Ce3+ ions under the excitation of 980nm, and the quantitative studies were carried out to elucidate the ET mechanism via calculating the microscopic parameters and phonon contribution ratios. Meanwhile, the thermal stability of glass hosts increases slightly with the introduction of B2O3 oxide. Furthermore, the 1.53μm band optical signal amplification was simulated based on the rare-earth ion rate and light power propagation equations. An increment in signal gain by about 1.4dB at 1532nm was observed in the Er3+/Ce3+ co-doped tellurite glass fiber containing 6mol% amount of B2O3 oxide, and the maximum signal gain reaches to 31dB on a 50cm fiber pumped at 980nm with power 200mW. The present results indicate that the prepared Er3+/Ce3+ co-doped tellurite glass modified by an appropriate amount of B2O3 oxide has good prospect as a gain medium applied for 1.53μm band EDFAs and lasers.

Modified rod-in-tube for high-NA tellurite glass fiber fabrication: materials and technologies.

In this paper, we report the whole fabrication process for high-numerical aperture (NA) tellurite glass fibers from material preparation to preform fabrication, and eventually, fiber drawing. A tellurite-based high-NA (0.9) magneto-optical glass fiber was drawn successfully and characterized. First, matchable core and cladding glasses were fabricated and matched in terms of physical properties. Second, a uniform bubble-free preform was fabricated by means of a modified rod-in-tube technique. Finally, the fiber drawing process was studied and optimized. The high-NA fibers (∅(core), 40-50 μm and ∅(cladding), 120-130 μm) so obtained were characterized for their geometrical and optical properties.

Nanodiamond in tellurite glass Part II: practical nanodiamond-doped fibers

Tellurite glass fibers with embedded nanodiamond are attractive materials for quantum photonics applications. Reducing the loss of these fibers in the 600-800 nm wavelength range of nanodiamond fluorescence is essential to exploit the unique properties of nanodiamond in the new hybrid material. The first part of this study reported the origin of loss in nanodiamond-doped glass and impact of glass fabrication conditions. Here, we report the fabrication of nanodiamond-doped tellurite fibers with significantly reduced loss in the visible through further understanding of the impact of glass fabrication conditions on the interaction of the glass melt with the embedded nanodiamond. We fabricated tellurite fibers containing nanodiamond in concentrations up to 0.7 ppm-weight, while reducing the loss by more than an order of magnitude down to 10 dB/m at 600-800 nm.

Nanodiamond in tellurite glass Part I: origin of loss in nanodiamond-doped glass

Tellurite glass fibers with embedded nanodiamond are attractive materials for quantum photonic applications. Reducing the loss of these fibers in the 600-800 nm wavelength range of nanodiamond fluorescence is essential to exploit the unique properties of nanodiamond in the new hybrid material. In the first part of this study, we report the effect of interaction of the tellurite glass melt with the embedded nanodiamond on the loss of the glasses. The glass fabrication conditions such as melting temperature and concentration of NDs added to the melt were found to have critical influence on the interaction. Based on this understanding, we identified promising fabrication conditions for decreasing the loss to levels required for practical applications.

Towards Water-Free Tellurite Glass Fiber for 2–5 μm Nonlinear Applications

We report our recent progress on fabricating dehydrated tellurite glass fibers. Low OH content (1 ppm in weight) has been achieved in a new halogen-containing lead tellurite glass fiber. Low OH-induced attenuation of 10 dB/m has been confirmed in the range of 3–4 µm using three measurement methods. This shows the dehydrated halo-tellurite glass fiber is a promising candidate for nonlinear applications in a 2–5 µm region.

Energy transfer and enhanced 1.53 µm band signal gain in Er3+/Ce3+ codoped tellurite glass fiber

A detailed study of the energy transfer between Er3+ and Ce3+ ions and its enhanced effects on the 1.53µm band signal gain in Er3+/Ce3+ codoped tellurite glass fiber under the excitation of 980nm is reported. The absorption spectra, visible upconversion spectra, infrared fluorescence spectra of Er3+ doped and Er3+/Ce3+ codoped glass samples were measured, and the 1.53µm band signal gain of Er3+ doped and Er3+/Ce3+ codoped glass fiber was calculated based on the rate and power propagation equations. Codoping Ce3+ with Er3+ ions can significantly suppress the visible upconversion emission and meanwhile improves the 1.53µm band fluorescence, and an increment of about 6.4dB signal gain at 1532nm was found in a 40cm glass fiber with 150mW pumping power at 980nm, which is ascribed to the energy transfer between Er3+ and Ce3+ ions. The quantitative analysis showed that the energy transfer between Er3+ and Ce3+ ions is a one phonon and two phonon-assisted energy transfer process. The results indicated that Er3+/Ce3+ codoping is a suitable scheme for low phonon energy tellurite glass fiber applied for broadband and high gain EDFA.

Erbium‐Ion‐Doped Tellurite Glass Fibers and Waveguides—Devices and Future Prospective: Part II

Following on from Part I of this review article that focuses on the suitability of Er3+‐doped tellurium oxide glass for optical amplification in fiber, this Part II article describes how the fiber gain data were then employed to engineer amplification in waveguides, which can be integrated with semiconductor pump sources. The gain characteristics and bandwidth of a phosphate modified tellurite waveguide formed on a GaAs substrate are discussed. The limiting structural compatibility of Er3+‐doped tellurite glass with polydimethylsiloxane polymer for active–passive integration is overcome by adopting a nanoscale super‐lattice approach for waveguide engineering.

Fabrication and upconversion luminescence of Er3+/Yb3+ codoped TeO2–WO3–Na2O–Nb2O5–Al2O3 glass fibers

The tellurite fibers based on glasses with the composition TeO2–WO3–Nb2O5–Na2O–Al2O3–Er2O3–Yb2O3 were fabricated by the rod-in-tube technique using a Heathway drawing tower. The upconversion luminescence of Er3+/Yb3+ codoped tellurite glass fibers under 980nm excitation were investigated. The Er3+/Yb3+co-doped tellurite fibers show an efficient up-conversion process in comparison with the Er3+-doped tellurite fibers. The pump power dependent intensities were discussed, which showed that two photons are involved in the upconversion process.

Analysis of Faraday effect in multimode tellurite glass optical fiber for magneto-optical sensing and monitoring applications

The design and fabrication of a tellurite glass multimode optical fiber for magneto-optical applications are presented and discussed. The analysis of the polarization shows that an optical beam, linearly polarized at the fiber input, changes to elliptically polarized with an ellipticity of 1∶4.5 after propagating down the fiber. However, the elliptical distribution remains unchanged with or without an applied magnetic field, demonstrating that no circular dichroism occurs within the fiber. The Verdet constant of the tellurite glass in the fiber is measured to be 28±0.5 rad·(T·m)-1, diverging by less than 3% from the Verdet constant found on the same glass composition in bulk form. These results demonstrate the feasibility to develop reliable tellurite glass fibers by the preform drawing method for magneto-optical applications.

Ultra-broadband near-infrared emission in praseodymium ion doped germanium tellurite glasses for optical fiber amplifier operating at E-, S-, C-, and L-band

An efficient method for achieving ultra-broadband near-infrared signal amplification is proposed employing potential Pr3+ doped UV-sensitive germanium tellurite (NZPGT) glass fiber. The corresponding 1D2 → 1G4 transition emission covers from 1280 to 1680 nm with a full-width at half-maximum of 140 nm, and the associated emission cross-sections at 1390 and 1485 nm are derived to be 2.62 × 10−21 and 7.41 × 10−21 cm2, respectively. Large emission cross-section profile of Pr3+ in NZPGT glasses reveals that effective broadband amplification, especially at E- and S-band, is reasonable to be expected. Practicable operating mechanism of potential Pr3+ doped NZPGT glass fiber offers favorable prospects for rare-earth ion single-doped ultra-broadband signal amplifier.