We report on designing, fabrication and experimental characterization of highly nonlinear, tellurite glass photonic crystal fibers with engineered normal dispersion characteristics for coherent supercontinuum generation. Effectively single mode, air-hole lattice fibers, with measured, all-normal dispersion profiles as flat as -10 to -50 ps/mn/km over 1500-2400 nm wavelengths are developed and investigated. Supercontinuum spectra are measured for these fibers, with a spectral width covering 1100-2600 nm wavelengths under pumping with a robust, fixed-wavelength erbium fiber-based femtosecond laser, delivering 90 fs pulses, centered at 1560 nm with peak power below 40 kW. To the best of our knowledge, this is the first engineered microstructured fiber, which due to its high nonlinearity, enables a self-phase modulation and optical wave breaking-based supercontinuum pumped with a turn-key, 40 kW femtosecond laser at spectral widths obtainable with previous all-normal dispersion fiber designs only under pumping with systems delivering peak power in the MW range.
Intensity fluctuations in supercontinuum generation are studied in polarization-maintaining (PM) and non-PM all-normal dispersion tellurite photonic crystal fibers. Dispersive Fourier transformation is used to resolve the shot-to-shot spectra generated using 225 fs pump pulses at 1.55 μm, with experimental results well reproduced by vector and scalar numerical simulations. By comparing the relative intensity noise for the PM and non-PM cases, supported by simulations, we demonstrate the advantage of the polarization-maintaining property of the PM fibers in preserving low-noise dynamics. We ass…
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 fabric…
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 i…
Absorption spectra of Ni$^{2+}$ ions in 22WO$_3$--78TeO$_2$ tungstate-tellurite glass were studied and Ni$^{2+}$ extinction coefficient spectral dependence was derived in the 450 -- 2700 nm wavelength range. Computer modeling of the glass structure proved Ni$^{2+}$ ions to be in trigonal-distorted octahedral environment in the tungstate-tellurite glass. Tanabe-Sugano diagram for such an environment was calculated and good description of the observed spectrum of Ni$^{2+}$ ion was obtained. Basing on both absorption spectral range width and the extinction coefficient, nickel should be considered…
Mid-infrared spectral broadening is of great scientific and technological interest, which till date is mainly achieved using non-silica glass fibers, primarily made of tellurite, fluoride and chalcogenide glasses. We investigate broadband mid-infrared supercontinuum generation at very low power in semiconductor multiple quantum well (MQW) systems facilitated by electromagnetically induced transparency. 100 femto-seconds pulses of peak power close to a Watt have been launched in the electromagnetically induced transparency window of a 30 period 1.374 μm long MQW system. Broadband supercontinuum…
We present a method for making microbubble whispering gallery resonators (WGRs) from tellurite, which is a soft glass, using a CO$_2$ laser. The customized fabrication process permits us to process glasses with low melting points into microbubbles with loaded quality factors as high as $2.3 \times 10^6$. The advantage of soft glasses is that they provide a wide range of refractive index, thermo-optical and optomechanical properties. The temperature and air pressure dependent optical characteristics of both passive and active tellurite microbubbles are investigated. For passive tellurite microb…
Quantifying temperature variations at the micron scale can provide new opportunities in optical sensing. In this paper, we present a novel approach using the temperature-dependent variations in fluorescence of rare-earth doped tellurite glass to provide a micron-scale image of temperature variations over a 200 micrometre field of view. We demonstrate the system by monitoring the evaporation of a water droplet and report a net temperature change of 7.04 K with a sensitivity of at least 0.12 K. These results establish the practicality of this confocal-based approach to provide high-resolution ma…
We report on a self-organized process initiated on a potassium-tungsten-tellurite glass surface under repetitive femtosecond laser irradiation in a regime where cumulative effects lead to a localized melting. Specifically, we show that self-organized periodic patterns consisting of parallel nanoplanes perpendicular to the laser polarization are forming and extending beyond the zone under direct laser exposure. Examination of the modified regions revealed a phase change from a glassy tellurium-oxide to a crystalline elemental tellurium. In addition, we observe that this self-organization proces…
We present the results of work on a hybrid material composed of a tellurite glass rod doped with nanodiamonds containing nitrogen-vacancy-nitrogen and paramagnetic nitrogen-vacancy color centers. The reported results include details on tellurite glass and cane fabrication, confocal and wide-field imaging of the nanodiamond distribution in their volume, as well as on the spectroscopic characterization of their fluorescence and Optically Detected Magnetic Resonance measurements of magnetic fields and temperatures. Magnetic fields up to 50 G were examined with a sensitivity of 10$^{-5}$ T Hz$^{-1…
In this paper, we report the design and fabrication of a highly birefringent polarization-maintaining photonic crystal fiber (PM-PCF) made from chalcogenide glass, and its application to linearly-polarized supercontinuum (SC) generation in the mid-infrared region. The PM fiber was drawn using the casting method from As38Se62 glass which features a transmission window from 2 to 10 $μm$ and a high nonlinear index of 1.13.10$^{-17}$m$^{2}$W$^{-1}$. It has a zero-dispersion wavelength around 4.5 $μm$ and, at this wavelength, a large birefringence of 6.10$^{-4}$ and consequently strong polarization…
Spectral converters are known to increase photovoltaic energy conversion by minimizing losses due to fundamental non-absorption and thermalization processes, and have been suggested to surpass the Shockley-Queisser efficiency limit in single junction solar cells. Here we present a detailed spectroscopic study of photoluminescence in tellurite-tungstate glasses doped and codoped with $Pr^{3+}-Yb^{3+}$ and $Ag$ nanoparticles. The energy transfer mechanisms between $Pr^{3+}$ and $Yb^{3+}$ are discussed based on the near infrared emission under excitation at $442$ nm and on the upconversion emissi…
We investigate supercontinuum generation in several suspended-core soft-glass photonic crystal fibers pumped by an optical parametric oscillator tunable around 1550 nm. The fibers were drawn from lead-bismuth-gallium-cadmium-oxide glass (PBG-81) with a wide transmission window from 0.5-2.7 micron and a high nonlinear refractive index up to 4.3.10^(-19) m^2/W. They have been specifically designed with a microscale suspended hexagonal core for efficient supercontinuum generation around 1550 nm. We experimentally demonstrate two supercontinuum spectra spanning from 1.07-2.31 micron and 0.89-2.46 …
Blue-enhanced, broadband supercontinuum generation in a 50 um core fluorine-doped graded-index multimode fiber is demonstrated by pumping with a 1064 nm picosecond source. Multi-octave supercontinuum spectrum extending from ~400 nm to 2,400 nm is achieved in a relatively short fiber. The measured spectrum and multimode nonlinear properties are compared to those of a germanium-doped graded-index multimode fiber. It is shown that engineering the glass composition and thus its chromatic dispersion and absorption characteristics, provides a novel and effective approach to further controlling the n…
We report the amplification of an all-normal dispersion supercontinuum pulse in a Thulium / Holmium co-doped all-fiber chirped pulse amplification system. With a -20 dB bandwidth of more than 300 nm in the range 1800-2100 nm the system delivers high quality 66 fs pulses with more than 70 kW peak power directly from the output fiber. The coherent seeding of the entire emission bandwidth of the doped fiber and the stability of the supercontinuum generation dynamics in the silicate glass all-normal dispersion photonic crystal fiber result in excellent noise characteristics of the amplified ultras…
For the first time, we demonstrated that a hyper-broadband from 2μm to 10μm can be generated with a high spectral flatness by using a ~4 um pump and an As2Se3 photonic crystal fiber. The broad and flat dispersion profile and the low guiding loss of the endlessly single-mode As2Se3 photonic crystal fibers combining with the high nonlinearity and wide mid-infrared transparent window of As2Se3 chalcogenide glass are essential for this high performance mid-infrared laser source.
We propose and optimize theoretically a supercontinuum (SC) laser source in the mid-IR based on using As-Se-Te/As-S core/clad step-index fibers and a femtosecond all-fiber laser system at 2 μm. Numerically simulated spectra extending from ~1 μm to more than 8 μm are demonstrated for pump energy of order 100 pJ in a fiber with a core diameter of 2 μm. To the best of our knowledge, the possibility of such long-wavelength spectral conversion of pump pulses at the wavelength of 2 μm in optical fibers is demonstrated for the first time. The theoretical calculations are performed on the base of real…
The generation of a two-octave supercontinuum from the visible to mid-infrared (700 - 2800 nm) in a non-silica graded-index multimode fiber is reported. The fiber design is based on a nanostructured core comprised of two types of drawn lead-bismuth-gallate glass rods with different refractive indices. This structure yields an effective parabolic index profile, an extended transmission window, and ten times increased nonlinearity when compared to silica fibers. Using femtosecond pulse pumping at wavelengths in both normal and anomalous dispersion regimes, a detailed study is carried out into th…
A novel fiber-coupled ITO coated glass slide sensor for performing surface plasmon polariton chemical monitoring in the 3.5 um mid-IR range is reported. Efficient mid-IR fiber coupling is achieved with 3D laser written waveguides, and the coupling of glass waveguide modes to ITO SPPs is driven by the varying phase matching conditions of different aqueous analytes across the anomalous dispersion range determined by their molecular fingerprints. By means of using both a mid-IR fiber supercontinuum source and a diode laser the excitation of SPPs is demonstrated. The efficient optical monitoring o…
We designed and developed tapered suspended-core fibers of high-purity As39Se61 glass for supercontinuum generation in the mid-IR with a standard fiber laser pump source at 2 $μ$m. It was shown that microstructuring allows shifting a zero dispersion wavelength to the range shorter than 2 $μ$m in the fiber waist with a core diameter of about 1 $μ$m. In this case, supercontinuum generation in the 1-10 $μ$m range was obtained numerically with 150-fs 100-pJ pump pulses at 2 $μ$m. We also performed experiments on wavelength conversion of ultrashort optical pulses at 1.57 $μ$m from Er: fiber laser s…
We report a novel technique for launching broadband laser light into liquid-filled hollow-core photonic crystal fiber (HC-PCF). It uniquely offers self-alignment and self-stabilization via optomechanical trapping of a fused silica nanospike, fabricated by thermally tapering and chemically etching a single mode fiber into a tip diameter of 350 nm. We show that a trapping laser, delivering ~300 mW at 1064 nm, can be used to optically align and stably maintain the nanospike at the core center. Once this is done, a broadband supercontinuum beam (~575 to 1064 nm) can be efficiently and close to ach…
The effective Kerr nonlinearity of hollow-core kagome-style photonic crystal fiber (PCF) filled with argon gas increases over 100 times when the pressure is increased from 1 to 150 bar, reaching 15 % of that of bulk silica glass, while the zero dispersion wavelength shifts from 300 to 900 nm. The group velocity dispersion of the system is uniquely pressure-tunable over a wide range while avoiding Raman scattering : absent in noble gases and having an extremely high optical damage threshold. As a result, detailed and well controlled studies of nonlinear effects can be performed, in both normal …
Compact, power efficient and fiber compatible lasers, wavelength converters and amplifiers are vital ingredients for the future fiber optic systems and networks. Nonlinear optical effects, like Raman scattering and parametric four wave mixing, offer a way to realize such devices. Here we use a single chalcogenide microwire to realize a device that provides the functions of a Stokes Raman parametric laser, a four wave mixing anti Stokes wavelength converter, and an ultra broadband Stokes/anti Stokes Raman amplifier or supercontinuum generator. The device operation relies on ultrahigh Raman and …
