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1

Influence of dispersion slope on soliton spectral tunneling in photonic crystal fiber

Yang Yunxia, Yang Hua, Tong Xiongfeng, Zhao Saili, Chen Shuyuan

Optica Applicata

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2021

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Vol. 51, nr 3

415--427

EN

We report a numerical investigation of how the dispersion slope affects the soliton spectral tunneling (SST) in a photonic crystal fiber with three zero dispersion wavelengths. It is discovered that a larger dispersion slope makes group-velocity mismatch between the initial soliton and the transferred wave thereby suppressing the SST effect, while a proper decrease of the dispersion slope enhances the SST effect to widen a supercontinuum range. Besides, we find a soliton-like leaking dispersion wave, which can sustain information and energy for a short time within a particular spectral range.

2

Numerical investigation of a broadband coherent supercontinuum generation in Ga₈Sb₃₂S₆₆ chalcogenide photonic crystal fiber with all-normal dispersion

Medjouri Abdelkader, Abed Djamel, Becer Zoubir

Opto-Electronics Review

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2019

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Vol. 27, No. 1

1--9

EN

All normal dispersion (ANDi) and highly nonlinear chalcogenide glass photonic crystal fiber (PCF) is proposed and numerically investigated for a broad, coherent and ultra-flat mid-infrared supercontinuum generation. The proposed PCF consists of a solid core made of Ga₈Sb₃₂S₆₆ glass surrounded by seven rings of air holes arranged in a triangular lattice. We show by employing the finite difference frequency domain (FDFD) method that the Ga₈Sb₃₂S₆₆ PCF dispersion properties can be engineered by carefully adjusting the air holes diameter in the cladding region and ANDi regime is achieved over the entire range of wavelengths with a zero chromatic dispersion around 4.5 μm. Moreover, we demonstrate that injecting 50 fs width and 20 kW peak power laser pulses (corresponding to a pulse energy of 1.06 nJ) at a pump wavelength of 4.5 μm into a 1 cm long ANDi Ga₈Sb₃₂S₆₆ PCF generates a broad, flat-top and perfectly coherent SC spectrum extending from 1.65 μm to 9.24 μm at the 20 dB spectral flatness. These results make the proposed Ga₈Sb₃₂S₆₆ PCF an excellent candidate for various important mid-infrared region applications including mid-infrared spectroscopy, medical imaging, optical coherence tomography and materials characterization.

3

Optimization of microstructured fibers with germanium-doped core for broad normal dispersion range

Biedrzycki J., Tarnowski K., Urbańczyk W.

Opto-Electronics Review

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2018

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Vol. 26, No. 1

57--62

EN

We have numerically studied different designs of technologically feasible microstructured fibers with a germanium-doped core in order to obtain normal dispersion reaching possibly far in the mid infrared. Hexagonal, Kagome and the combination of both geometries were numerically examined with respect to different constructional parameters like pitch distance, filling factor of air holes, number of layers surrounding the core, and level of germanium doping in the core. Our analysis showed that the broadest range of normal dispersion reaching 2.81 μm, while keeping an effective mode area smaller than 30 μm², was achieved for a hexagonal lattice and a 40 mol% GeO₂ doped core. The proposed fibers designs can be used in generation of a normal dispersion supercontinuum reaching the mid-IR region.

4

Światłowodowy generator promieniowania supercontinuum dużej mocy w zakresie widmowym 1,9-2,65 μm

Michalska M., Grześ P., Świderski J.

Elektronika : konstrukcje, technologie, zastosowania

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2018

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Vol. 59, nr 3

39--43

PL

W artykule przedstawiono światłowodowy układ laserowy generujący promieniowanie supercontinuum o mocy 8,76 W w zakresie widmowym 1,9-2,65 μm, z czego 2,44 W mocy promieniowania odpowiada falom dłuższym niż 2,4 um. Układ został opracowany na bazie jednostopniowego światłowodowego wzmacniacza tulowego pompowanego ciągiem impulsów o czasie trwania 1 ns powtarzanych z częstotliwością 500 kHz, o długości fali 1,55 μm. Długoterminowy pomiar stabilności generacji promieniowania opracowanego układu wykazał fluktuacje mocy wyjściowej poniżej 3%.

EN

The article presents a fiber supercontinuum generator delivering 8.76 W of average output power in a spectral band of ~1.9-2.65 μm out of which 2.44 W corresponded to wavelengths longer than 2.4 μm. A 1.55 μm pulsed laser system delivering 1 ns pulses at a pulse repetition frequency of 500 kHz was used as a seed source for a one-stage thulium-doped fiber amplifier. A long- term power stability test showed power fluctuations of < 3%.

5

Supercontinuum fiber laser source for water quality and heavy metals detection

Teh P. C., Ho Y. H., Ong C. E., Lee S. C., Lo P. K., Lai K. C., Yeap K. H., Loh S. H., Teh P. S., Tey K. L.

Optica Applicata

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2017

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Vol. 47, nr 3

445--456

EN

We report a compact, all fiber, 150 ps fiber master oscillator power amplifier operating at 1064 nm that has the ability of producing a maximum average output power of 2.16 W with peak power as high as 10 kW. The output from the master oscillator power amplifier is spliced with a highly nonlinear photonic crystal fiber, generating a supercontinuum with an average power of 250 mW at repetition rate of 1 MHz and spectrum bandwidth spanning from 600 to 1700 nm. The developed supercontinuum system is used to detect the presence of heavy metal contaminants in water by a simple light transmittance method to ensure that the water is free from heavy metal contaminants and safe for consumption. The supercontinuum laser source was shone onto a water sample with a detector placed at another end in order to measure the transmitted supercontinuum light. By measuring the amount of light attenuated at particular wavelength, the concentration of heavy metal contaminants present in the water sample could be determined.

6

Influence of Self-steepening and Higher Dispersion Effects on the Propagation Characteristics of Solitons in Optical Fibers

Thuy D. T., Vinh N.T., Thuan B. D., Van C. L.

Computational Methods in Science and Technology

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2016

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Vol. 22, No. 4

239--243

EN

In this paper we consider the influence of higher-order nonlinear effects like third-order dispersion, self-steepening effect on the propagation characteristics of solitons. By solving the higher-order nonlinear Schrödinger equation we show that the self-steepening effect can lead to the breakup of higher-order solitons through the phenomenon of soliton fission. This effect plays an essential role in several nonlinear phenomena, in particular in the so-called supercontinuum generation in optical fibers. Moreover, we can use third order dispersion to compress pulses as well as changing the frequency.

7

Dispersion management in soft glass all-solid photonic crystal fibres

Buczynski R., Pniewski J., Pysz D., Stepien R., Kasztelanic R., Kujawa I., Filipkowski A., Waddie A. J., Taghizadeh M. R.

Opto-Electronics Review

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2012

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Vol. 20, No. 3

207-215

EN

The development of all-solid photonic crystal fibres for nonlinear optics is an alternative approach to air-glass solid core photonic crystal fibres. The use of soft glasses ensures a high refractive index contrast (> 0.1) and a high nonlinear coefficient of the fibres. We report on the dispersion management capabilities in all-solid photonic crystal fibres taking into account four thermally matched glasses which can be jointly processed using the stack-and-draw fibre technique. We present structures with over 450 nm broadband flat normal dispersion and ultra-flat near zero anomalous dispersion below 5 ps/nm/km over 300 nm dedicated to supercontinuum generation with 1540 nm laser sources. The development of an all-solid photonic crystal fibre made of F2 and NC21 glasses is presented. The fibre is used to demonstrate supercontinuum generation in the range of 730–870 nm (150 nm) with flatness below 5 dB.

8

Near infrared transmission in dual core lead silicate photonic crystal fibres

Bookey H. T., Buczyński R., Wischnewski A., Pysz D., Kasztelanic R., Waddie A. J., Stepien R., Kar A. K., Taghizadeh M. R.

Optica Applicata

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2012

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Vol. 42, nr 1

75-83

EN

Photonic crystal fibres (PCF) can provide the high confinement needed to enable nonlinear optical processes to be studied in silicate fibre over short lengths without the need for large pulse energies. Additionally, the capillary stacking technique for PCF fabrication lends itself to the design of multiple core fibres and this capability has triggered much work into the properties of dual core PCF. In this paper, the effect of the dual core interaction on the nonlinear wavelength conversion is studied using a femtosecond oscillator in the near IR range. Effective supercontinuum generation in the range 1300-1700 nm is achieved in the anomalous dispersion regime.

9

Setting an Upper-Wavelength Limit to the Supercontinuum Generated in a Photonic Crystal Fibre

Tartara L., Degiorgio V., Cherif R., Zghal M.

Journal of Telecommunications and Information Technology

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2009

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nr 1

34-37

EN

We report about a novel kind of supercontinuum generation in a photonic crystal fibre in which the spectral broadening occurs only on the blue side of the pump wavelength. As a consequence a limit to the extent of the supercontinuum is set and thus a way for tailoring the broadened spectrum according to a peculiar application is provided. We present a theoretical explanation along with experimental data which are supported by the results of a set of numerical simulations.

10

Poszerzenie widma impulsu laserowego poprzez zastosowanie przewężki dwustronnej na standardowym włóknie jednomodowym

Stasiewicz K. A., Młyńczak J., Jaroszewicz L. R., Kopczyński K.

Biuletyn Wojskowej Akademii Technicznej

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2007

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Vol. 56, nr 4

155-165

PL

Praca przedstawia eksperymentalne wyniki poszerzenia impulsu laserowego dużej mocy w standardowych światłowodach telekomunikacyjnych. Poszerzenie uzyskano poprzez wykorzystanie technologii przewężki dwustronnej, której optymalizacja dla danego typu włókna pozwala na sterowanie tak szerokością impulsu jak i składem widmowym wychodzącej wiązki, prowadząc w konsekwencji do generacji światła białego.

EN

The papers describes the results of a laser pulse broadening in tapered standard single mode fiber. Additional description of a set - up for taper manufacturing, with a principle of its operation, based on elongation procedure of fiber-optics in a low-pressure gas burner, is also presented. A virtue of such a set-up is the possibility of different kinds of taper manufacturing, like punctual, long distance on regular or increasing distance. Tapering process allows us to change a diameter of an optical fiber what means boundary condition changes, beam is propagating in a core (made from silica) surrounded by air. There is a large refractive index step between these two media, allowing for confined pulse (with high power) in a very small area. This effect causes increasing intensity of a propagated beam and amplifies nonlinear effects, like self-phase modulation etc. The article presents the results of pulse broadening obtained in different tapers, made on a single-mode fiber for a wavelength of 1310 nm and a core diameter of about 9 žm. As a light source, the pumped laser operated at a wavelength of 532 nm, which emitted the pulses of 0.6 ns with a repetition rate of about 1 kHz, has been used. All the measured fibers with a taper have a length of about 3 m, where about 1.2 m was for the input (for easier launching) and the output (for easier connection with an optical spectrum analyzer). Experimental results show the pulse broadening in the used taper structures. The best result are obtained for a long distance taper, where the elongated part was about 50 mm (flame brush is travelling to and from along the constant length). For this taper, it can be observed more flat spectrum broadening to the longer wavelength, together with increasing average power of a laser. Theoretically the best broadening we should obtain for a taper length of about 100 mm what will be one of the next subjects of our research. Other tapers also cause broadening effects but their spectra are not so flat. Interesting example is a taper with an increasing length of elongation. We observed additional spectral pick at the wavelength of about 630 nm and 950 nm. These picks are connected with the smaller core diameter obtained in this type of tapering process (the smaller core, the larger broadening). The worst results were for a punctual taper. In this case, a diameter of a taper is very small (about several micrometers) but the losses are very high. The presented results show that biconical tapered single mode optical fiber is a good way to obtain spectral broadening (supercontinuum effect).

11

Spectral modification of supercontinuum light by means of fs-light pulses optimized in a closed learning loop

Lindinger A., Plewicki M., Weber S.M., Lupulescu C., Wöste L.

Optica Applicata

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2004

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Vol. 34, nr 3

341-347

EN

First closed loop optimization experiments on the spectral envelope of white light produced by shaped fs pulses irradiated on a thin (2 mm) sapphire plate are presented. Thereby, the spectral position of the maximal white light intensity could overall be shifted by about 80 nm. The modification of this spectral characteristic due to non-linear effects in optimal control is discussed with regard to novel applications in laser development.