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ABSTRACT: We investigate supercontinuum (SC) generation in highly nonlinear tellurite microstructured fibers pumped by a continuous wave (cw)/quasi-cw laser. We investigate two types of tellurite fibers. One type has the constant core diameter, and the other type has a longitudinally varying core diameter. For the fibers with a constant core diameter, when pumped in the anomalous dispersion region, the SC is symmetric in a fiber that has a zero dispersion wavelength close to the pump wavelength. For the fibers with a longitudinally varying diameter, the calculated phase-matching conditions show that they have a broad wavelength range of dispersive waves, and therefore the measured SC spectrum can be broader than one octave. In this work, the fiber lengths are as short as several tens of centimeters, and the pump power is in the watt level.
Optics Letters 06/2012; 37(11):2127-9. · 3.40 Impact Factor
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ABSTRACT: We report tellurite composite microstructured optical fibers with small core surrounded by air holes and two glass claddings with low refractive index. In which near zero, ultra-flattened dispersion is realized.
05/2012;
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ABSTRACT: We demonstrate quasi-continuous wave supercontinuum generation in a single-mode high-nonlinear fiber (HNLF) in 1.55 μm band, which is pumped by the amplified passively Q-switched submicrosecond pulse. The pump wavelength is in the normal dispersion region of HNLF and near to the zero-dispersion wavelength. The broad SC spectral range from 1200 to 2260 nm is obtained with the low pump peak power of 17.8 W. The 20 dB bandwidth of 922 nm from 1285 to 2207 nm is obtained with the assumption that the peak near 1560 nm is filtered. The spectrum density for the 20 dB bandwidth is from -27.5 to -7.5 dbm/nm.
Applied Optics 05/2012; 51(13):2346-50. · 1.41 Impact Factor
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ABSTRACT: We demonstrate an all-fiber broadband supercontinuum (SC) source with high efficiency in a step-index high nonlinear silica fiber, which was pumped by a 1557 nm subpicosecond-pulse laser in the normal dispersion region. The broad SC spectrum covers the spectral range from 840 to 2390 nm, and the 10 dB bandwidth from 1120 nm to 2245 nm of the SC covers one octave, assuming the peaks near 1550 nm were filtered. The SC source system is constructed by all-fiber components, which can be fusion-spliced together directly with low loss, less than 0.1 dB. Thus the SC source has high energy transfer efficiency from the pump source. The maximum SC average power of 332 mW is obtained, including the peaks near 1550 nm. The spectral density for the 10 dB bandwidth is in the range from -17.3 to -7.3 dBm/nm.
Applied Optics 03/2012; 51(8):1071-5. · 1.41 Impact Factor
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ABSTRACT: We demonstrate theoretically and experimentally that it is feasible to draw the microstructured fiber with longitudinally varying diameter (FLVD) whose diameter varies sharply in a short fiber length. It is elucidated that during the fiber drawing process the tension is linearly proportional to the natural logarithm of the fiber drawing speed. As a result, the tension is not so sensitive to the fiber diameter. Moreover, this sensitivity can be decreased by using a large diameter ratio of preform to fiber. Owing to the low sensitivity the FLVD with diameter varying sharply in a short fiber length can be drawn directly from the preform. Additionally we show that the microstructural geometry of FLVD does not depend on the varying diameter. The deformation in microstructural geometry is determined by the fiber segment with the smallest diameter. We fabricate a FLVD of which the diameter decreases by 75% in a fiber length of 10 cm. By using this fiber we demonstrate the 600-1800 nm supercontinuum (SC) generation and the 532 nm second harmonic generation pumped by a picosecond fiber laser. The SC spectra by the conventional fibers with the largest and the smallest diameters of the FLVD are also shown, respectively. The comparisons show that the FLVD has the broadest SC spectrum due to its high nonlinearity, varying dispersion, and high damage threshold.
Optics Express 01/2012; 20(2):1141-50. · 3.59 Impact Factor
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Weiqing Gao,
Meisong Liao, Xin Yan,
Chihiro Kito,
Tomas Kohoutek,
Takenobu Suzuki,
Mohammed El-Amraoui,
Jean-Charles Jules,
Grégory Gadret,
Frédéric Désévédavy,
Frédéric Smektala,
Yasutake Ohishi
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ABSTRACT: We demonstrate visible light generation in chalcogenide
As2S3 microstructured optical fiber. The generated
visible light causes irreversible damage to the fiber core because of
the high absorption coefficient of chalcogenide glasses in the visible
band. The SCs (supercontinua) are measured in both untapered and tapered
As2S3 fibers, no wider SC is obtained in the
tapered one. The SC growth is prevented by the visible light generation
since the damage to the fiber core decreases the fiber transmission
substantially. This effect can be avoided by designing the fiber to
enable the pump source to work in single-mode operation.
Applied Physics Express 09/2011; 4(10):2601. · 3.01 Impact Factor
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ABSTRACT: We try to obtain stable supercontinuum (SC) generation with broad bandwidth under relative simple pump conditions. We use a 1.3-m-long highly nonlinear tellurite microstructured fiber and pump it by a 15 ps 1064 nm fiber laser. One segment of the fiber is tapered from a core diameter of 3.4 μm to 1.3 μm. For the first time five-order stimulated Raman scatterings (SRSs) are observed for soft glass fibers. SC covering 730-1700 nm is demonstrated with the pump-pulse-energy of several nJ. The mechanisms of SC broadening are mainly SRS, self-phase modulation (SPM) and cross phase modulation (XPM). The tapered segment has two advantages. Firstly it increases the nonlinearity of fiber by several times. Secondly, it acts as a compensation for the dispersion of the untapered segment, and mitigates the walk-off between pump pulse and SRS peaks.
Optics Express 08/2011; 19(16):15389-96. · 3.59 Impact Factor
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ABSTRACT: In this paper, the tellurite composite microstructured optical fibers consist of different glasses have been fabricated for the first time. This structure provides a novel freedom of dispersion engineering. Broad supercontinuum spectrum was generated with femtosecond laser pumping. Fibers with much flattened dispersion are in progress.
Lasers and Electro-Optics Europe (CLEO EUROPE/EQEC), 2011 Conference on and 12th European Quantum Electronics Conference; 06/2011
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ABSTRACT: We propose a distortion factor which indicates the distortion degree of the geometry of fiber compared with the geometry of preform. Hexagonal core, and triangular core nanostructured fibers with the smallest size are demonstrated.
Lasers and Electro-Optics (CLEO), 2011 Conference on; 06/2011
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ABSTRACT: We report on the Raman response function and the soliton self-frequency shift in a tellurite microstructured fiber pumped at 1557 nm. The Raman response function in a tellurite fiber quantifies a contribution of the Raman fraction to the nonlinear optical response. Continuous soliton wavelength shift from 1582 to 1851 nm is observed in a tellurite microstructured optical fiber with the length of 6.5 cm. The experimental results strongly correlated with the numerical simulations based on a generalized nonlinear Schrödinger equation.
Journal of Applied Physics 01/2011; · 2.17 Impact Factor
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ABSTRACT: For a suspended core nanofiber, the holey region is expected to be as large as possible to propagate the light at wavelengths as long as possible. Additionally, a large holey region is significant for its applications in sensors. However, the fabrication of nanofiber with large holey region is still a challenge so far. In this paper a method, which involves pumping positive pressure of nitrogen gas in both the cane fabrication and fiber-drawing processes, was proposed. A suspended core nanofiber, with a core diameter of around 480 nm and an unprecedented diameter ratio of holey region to core (DRHC) of at least 62, was fabricated in the length of several hundred meters. Owing to the large holey region, the confinement loss of the suspended core nanofiber is insignificant when the wavelength of light propagated in it is 1700 nm. For this fabrication technique, the nanowire length, fabrication efficiency, and the uniformity in the diameter are much superior to those of the nanowires fabricated in other ways. Finally, single mode third harmonic generation was observed by this nanofiber under the pump of a 1557 nm femtosecond fiber laser. This work shows the prospect of fabrication of nanostructured waveguide in glass materials by an inflation technique.
Optics Express 04/2010; 18(9):9088-97. · 3.59 Impact Factor
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ABSTRACT: A dispersion controlled highly nonlinear tellurite complex microstructure fiber whose chromatic dispersion is flatter than that of the previous ones is realized. Broad supercontinuum generation was demonstrated under the several hundred pJ femtosecond pulse pumping.
03/2010;
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ABSTRACT: We demonstrate four-wave mixing-based broadband (>68 nm ) wavelength conversion and flattened supercontinuum generation spanning from 900 to 2800 nm in a 36-cm-long tellurite microstructured fiber which has a high nonlinearity. By reducing the size of air holes of the tellurite microstructured fibers, single mode propagation and small dispersion slope are obtained without the propagation loss enhancement. Our results show that chromatic-dispersion controlled tellurite microstructured fibers are promising candidates for nonlinear applications.
Journal of Applied Physics 03/2010; · 2.17 Impact Factor
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ABSTRACT: We report wide and flattened supercontinuum generation in zero-dispersion-wavelength-decreasing tellurite microstructured fibers fabricated by using the tapering method. Flattened supercontinuum light expanding from 600to2800 nm can be generated when launching a 1550 nm femtosecond fiber laser into a 5-cm-long, zero-dispersion-decreasing, tellurite microstructured fiber. Our results show that short length (several centimeter) zero-dispersion-wavelength decreasing highly nonlinear fiber has a potential for generating wide and flattened supercontinuum light sources.
Optics Letters 01/2010; 35(2):136-8. · 3.40 Impact Factor
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ABSTRACT: We report what we believe to be the first demonstration of the second and third harmonics in tellurite microstructured fibers pumped by a 1557 nm femtosecond fiber laser. The intensities of the second and third harmonics are enhanced by increasing the nonlinear coefficient of the tellurite microstructured fiber. By using tellurite microstructured fiber with a core diameter of approximately 2.7 microm, supercontinuum light expanding from 470 nm to 2400 nm could be achieved. The effects of the fiber-core diameter on the flatness of the supercontinuum light are also investigated when pumped at 1557 nm.
Optics Letters 01/2010; 35(1):58-60. · 3.40 Impact Factor
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ABSTRACT: A highly nonlinear composite fiber, which has a 1.5 microm chalcogenide glass core surrounded by a tellurite glass microstructure cladding, has been fabricated by the method of stack and draw. A tellurite glass capillary containing a As(2)S(3) rod was sealed with negative pressure inside. Then this capillary and other empty capillaries were stacked into a tellurite glass tube, and elongated into a cane. This cane was then inserted into another tellurite glass jacket tube and drawn into the composite microstructure fiber. The fiber has a flattened chromatic dispersion together with a zero dispersion wavelength located in the near infrared range. The propagation losses at 1.55 microm were 18.3 dB/m. The nonlinear coefficient at 1.55 microm was 9.3 m(-1)W(-1). Such a high nonlinear coefficient counteracts the high propagation losses to a large extent. A supercontinuum spectrum of 20-dB bandwidth covering 800-2400 nm was generated by this composite microstructure fiber.
Optics Express 11/2009; 17(24):21608-14. · 3.59 Impact Factor
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ABSTRACT: We report broad near-infrared soliton and associated dispersive wave source generation (1228–1867 nm) and tunable green third harmonic generation (528–542 nm) by LP11 mode excitation in a few-mode tellurite microstructure fiber pumped by a 1557 nm femtosecond fiber laser. The fiber presents a wide range of wavelengths in which the fundamental mode experiences normal dispersion, whereas the higher-order modes propagate in the anomalous dispersion regime. LP01 or LP11 mode can be selectively excited, and obviously different spectra are obtained based on the different mechanisms of supercontinuum generation.
Applied Physics Letters 10/2009; 95(17):171107-171107-3. · 3.84 Impact Factor
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ABSTRACT: A supercontinuum spectrum covering 800-2400 nm was generated by a chalcogenide-tellurite composite microstructure fiber, which was designed to have a high nonlinear coefficient together with a flattened chromatic dispersion in the near infrared range.
Optical Communication, 2009. ECOC '09. 35th European Conference on; 10/2009
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ABSTRACT: We report what we believe to be the first demonstration of supercontinuum generation from UV to 3.85 mum in a 2.5 cm long fluoride fiber pumped by a 1450 nm femtosecond laser.
Optical Communication, 2009. ECOC '09. 35th European Conference on; 10/2009
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ABSTRACT: Ultrabroadband supercontinuum light expanding from ultraviolet to 6.28 μm is generated in a centimeter-long fluoride fiber pumped by a 1450 nm femtosecond laser. The spectral broadening in the fluoride fiber is caused by self-phase modulation, Raman scattering and four-wave mixing. The experimental and simulated results show that fluoride fiber is a promising candidate for generating the midinfrared supercontinuum light up to 8 μm.
Applied Physics Letters 10/2009; 95(16):161103-161103-3. · 3.84 Impact Factor
