Journal articles: 'Modelling fibre lasers'

1

Aakjer, T., and J. H. Povlsen. "Modelling of cross-phase-modulated fibre lasers." Optical and Quantum Electronics 27, no. 10 (October 1995): 859–69. http://dx.doi.org/10.1007/bf00558478.

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Michalska, Maria, Paweł Grześ, and Jacek Swiderski. "High power, 100 W-class, thulium-doped all-fiber lasers." Photonics Letters of Poland 11, no. 4 (December 31, 2019): 109. http://dx.doi.org/10.4302/plp.v11i4.953.

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In this work, sub-kilowatt, compact thulium-doped fiber laser systems, operating at a wavelength of 1940 nm, have been presented. The continuous-wave laser power generated out of a single oscillator was 90 W with a slope efficiency of 56.7%. Applying a master oscillator – power amplifier configuration, an output power of 120.5 W with a slope efficiency of 58.2% was demonstrated. These are the first results of the works aimed at developing kW-class “eye-safe” laser systems in Poland. Full Text: PDF ReferencesZ. Liu, et al., "Implementing termination analysis on quantum programming", Sci. China Inf. Sci. 62, 41301 (2019) CrossRef S. D. Jackson, A. Sabella, D.G Lancaster, "Application and Development of High-Power and Highly Efficient Silica-Based Fiber Lasers Operating at 2 μm", IEEE J. Sel. Top. Quantum Electron. 13, 567, (2007). CrossRef E. Russell, N. Kavanagh, K. Shortiss, and F. C. G. Gunning, "Development of thulium-doped fibre amplifiers for the 2μm waveband", Proc. SPIE 10683, 106832Q (2018) CrossRef P. Peterka, B. Faure, W. Blanc, M. Karásek, and B. Dussardier, "Theoretical modelling of S-band thulium-doped silica fibre amplifiers", Opt. Quantum Electron. 36, 201 (2004) CrossRef M. Eichhorn, "Pulsed 2 μm fiber lasers for direct and pumping applications in defence and security", Proc. SPIE 7836, 78360B (2010). CrossRef O. Traxer and E. X. Keller, "Thulium fiber laser: the new player for kidney stone treatment? A comparison with Holmium:YAG laser", World J. Urol. 2019 Feb 6. doi: 10.1007/s00345-019-02654-5 CrossRef S. Das, "Optical parametric oscillator: status of tunable radiation in mid-IR to IR spectral range based on ZnGeP2 crystal pumped by solid state lasers", Opt. Quant. Electron. 51, 70 (2019) CrossRef M. Michalska, P. Hlubina, and J. Swiderski, "Mid-infrared Supercontinuum Generation to ∼4.7 μm in a ZBLAN Fiber Pumped by an Optical Parametric Generator", IEEE Photon. J 9, 3200207 (2017) CrossRef https://www.ipgphotonics.com DirectLink M.D. Burns, P. C. Shardlow, P. Barua, T. L. Jefferson-Brain, J. K. Sahu, and W. A.Clarkson, "47 W continuous-wave 1726 nm thulium fiber laser core-pumped by an erbium fiber laser", Opt. Lett. 44, 5230 (2019) CrossRef S.D. Jackson, "Cross relaxation and energy transfer upconversion processes relevant to the functioning of 2 μm Tm3+-doped silica fibre lasers", Opt. Commun. 230, 197 (2004). CrossRef X. Wang, P. Zhou, X. Wang, H. Xiao, and L. Si, "102 W monolithic single frequency Tm-doped fiber MOPA", Opt. Express 21, 32386 (2013) CrossRef K. Yin, R. Zhu, B. Zhang, G. Liu, P. Zhou, and J. Hou, "300 W-level, wavelength-widely-tunable, all-fiber integrated thulium-doped fiber laser", Opt. Express 24, 11085 (2016) CrossRef G. D. Goodno, L. D. Book, and J. E. Rothenberg, "600-W, single-mode, single-frequency thulium fibre laser amplifier", Proc. SPIE 7195, 71950Y (2009). CrossRef T. Ehrenreich, R. Leveille, I. Majid, K. Tankala, G. Rines, and P. Moulton, "1-kW, all-glass Tm: fiber laser", Proc. SPIE 7580, 1 (2010) DirectLink M. Michalska et al., "Highly stable, efficient Tm-doped fiber laser—a potential scalpel for low invasive surgery", Laser Phys. Lett. 13, 115101 (2016). CrossRef

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Yarutkina, I. A., and O. V. Shtyrina. "Mathematical modelling of dispersion-managed thulium/holmium fibre lasers." Quantum Electronics 43, no. 11 (November 30, 2013): 1019–23. http://dx.doi.org/10.1070/qe2013v043n11abeh015204.

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Komorowski, Paweł, Krzysztof Anders, Urszula Zdulska, and Ryszard Piramidowicz. "Erbium doped ZBLAN fiber laser operating in the visible - feasibility study." Photonics Letters of Poland 9, no. 3 (September 30, 2017): 85. http://dx.doi.org/10.4302/plp.v9i3.769.

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This work is focused on developing all-fiber green laser in hybrid geometry, based on combination of Er:ZBLAN active fiber and silica fiber-based passive components of optical resonator and deploying Fiber Bragg Gratings (FBGs) as highly selective mirrors for green spectral range. The scope of work covers fundamental spectroscopic characterization of Er:ZBLAN samples, determination of key spectroscopic parameters, modelling the lasing properties and lasing experiments in different pumping geometries. Full Text: PDF ReferencesW.P. Risk, T.R. Gosnell, A.V. Nurmikko, "Compact blue-green lasers", Cambridge University Press. (2003) CrossRef J.Y. Allain, M. Monerie, and H. Poignant, "Tunable green upconversion erbium fibre laser", Electronics Lett., 28 (1992) 111-113 CrossRef Z . Luo, Q. Ruan, M. Zhong, Y. Cheng, R. Yang, B. Xu, H. Xu, Z. Cai, "Compact self-Q-switched green upconversion Er:ZBLAN all-fiber laser operating at 543.4 nm", Optics Lett. 41 (2016) 2258-2261 CrossRef D. E. McCumber, "Einstein relations connecting broadband emission and absorption spectra", Physical Review 136 (1964) 954-957 CrossRef

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Wang, Jiaxin, Mohammad Ahmad, and Terence A. King. "Theoretical Modelling of Thulium-sensitized Holmium Continuous-wave Fibre Lasers." Journal of Modern Optics 41, no. 7 (July 1994): 1457–72. http://dx.doi.org/10.1080/09500349414551391.

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Jackson, S. D., T. A. King, and M. Pollnau. "Modelling of high-power diode-pumped erbium 3 μm fibre lasers." Journal of Modern Optics 47, no. 11 (September 2000): 1987–94. http://dx.doi.org/10.1080/09500340008232450.

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Jackson, S. D., T. A. King, and M. Pollnau. "Modelling of high-power diode-pumped erbium 3 μ m fibre lasers." Journal of Modern Optics 47, no. 11 (September 15, 2000): 1987–94. http://dx.doi.org/10.1080/095003400417133.

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8

Razukov, V. A., L. A. Melnikov, P. V. Kuptsov, and K. S. Gochelashvili. "Modelling light wave propagation and interaction and dynamical regimes analysis using the Lyapunov exponents method in ring fibre cavities." Laser Physics 33, no. 2 (January 27, 2023): 025004. http://dx.doi.org/10.1088/1555-6611/acaea1.

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Abstract The ‘Cabaret’ finite differences method allows the performance of fast and conclusive modelling of the microcavity temporal dynamics with group velocity dispersion, cross- and self- phase modulation included. The proposed scheme and model allow us to study the dynamics of a cavity with two counter-propagating pulses, second order dispersion, modulation instability, Rayleigh scattering and other effects along the cavity roundtrips number up to 106…7. The possibility of Lyapunov exponents mapping for the Raman and SBS fibre lasers and cavities is discussed.

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Mousavi, Laleh, and Mohammad Sabaeian. "Numerical modelling of self-heating effects on guiding modes of high-power photonic crystal fibre lasers." Lithuanian Journal of Physics 53, no. 2 (2013): 104–11. http://dx.doi.org/10.3952/physics.v53i2.2670.

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Ahmed, Moustafa, Safwat W. Z. Mahmoud, and Minoru Yamada. "Numerical analysis of optical feedback phenomenon and intensity noise of fibre-grating semiconductor lasers." International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 20, no. 3 (2007): 117–32. http://dx.doi.org/10.1002/jnm.639.

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Li, Wang, Chen Bai, Chen Jia-Lin, Chang Li-Ping, Li Guo-Yang, Sun An, and Lin Zun-Qi. "Theoretical modelling of the effect of photon lifetime on the output dynamics of Er-doped distributed feedback fibre lasers." Chinese Physics B 17, no. 1 (January 2008): 217–23. http://dx.doi.org/10.1088/1674-1056/17/1/038.

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Kutin, A. A., and M. V. Turkin. "Advanced Fiber Laser Perforation Technology for Thermoplastic Pre-Preg Material." Key Engineering Materials 496 (December 2011): 36–43. http://dx.doi.org/10.4028/www.scientific.net/kem.496.36.

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A study concerning the application of fiber laser to perforate thermoplastic pre-pregs is presented. An IPG fiber laser was used to drill arrays of holes in PEKK carbon-fiber composite pre-preg material. Perforated holes were of the order of 100μm. The effects of laser perforation process parameters including the number of pulses on the geometry of the resultant holes and the thermal damage to the matrix and fibres have been investigated. Dimensional analysis and experimental results have been used to construct the laser perforation process model. Keywords: Laser perforation; Fibre laser; Process modelling; Polymer matrix composites.

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13

Glorieux, Pierre. "Control of Chaos in Lasers by Feedback and Nonfeedback Methods." International Journal of Bifurcation and Chaos 08, no. 09 (September 1998): 1749–58. http://dx.doi.org/10.1142/s0218127498001455.

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Analytical approaches of the theory of chaos control in class B lasers are presented in the cases of continuous delayed feedback and of subharmonic modulation. They are compared with experimental findings on a CO 2 laser and a Nd-doped fiber laser with modulated loss and pump respectively. In both cases, analytical theory allows one to predict the shift of the first period-doubling bifurcations, Numerical simulations show that subharmonic modulation may induce shifts, crises and new attractors in a laser with modulated parameters and that its phase relative to the main modulation allows one to control the laser dynamics. These results agree well with the experimental observations on control of chaos in CO 2 and fiber lasers.

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Luo, Cheng-Jhih, and Yinchieh Lai. "Relative Intensity Noise of Hybrid Mode-Locked Bound Soliton Fiber Laser: Theory and Experiment." Applied Sciences 8, no. 9 (August 24, 2018): 1451. http://dx.doi.org/10.3390/app8091451.

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Relative intensity noises (RIN) of mode-locked lasers are properties which are crucial for applications. In the literature, there have been plenty of theoretical/experimental studies on the RIN noises of passive/active single-pulse mode-locked lasers. Since some mode-locked lasers can also be operated under the bound-pulse mode-locking state, it is thus very interesting to further examine the RIN properties under bound-pulse mode-locking, and to verify if there are possibilities for RIN noise reduction as predicted by some previous theoretical works. The conventional analytical formula based on the soliton perturbation theory can no longer be applied due to the pulse shape complexity for the bound-pulse mode-locking cases. New theoretical tools for modelling general mode-locked lasers are eagerly awaited. In the present work, the RIN noises of an environmentally stable 10 GHz hybrid mode-locked Er-doped fiber laser capable of bound-soliton generation are experimentally investigated, and a novel theoretical method based on the linearized backpropagation approach is theoretically developed for calculating the RIN noise spectra of general mode-locked lasers. Both the theoretical and experimental results demonstrate that the RIN noise of the bound-soliton state can be lower than that of the single-soliton state by following the laser power scaling tendency.

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Художиткова, Дарья Алексеевна. "Optimization of a mode-locked fiber laser based on nonlinear polarization rotation using genetic algorithm." Вычислительные технологии, no. 4(25) (September 16, 2020): 20–30. http://dx.doi.org/10.25743/ict.2020.25.4.003.

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Выполнено математическое моделирование волоконного лазера с синхронизацией мод на основе эффекта нелинейного вращения поляризации. Проведена оптимизация лазера с использованием генетического алгоритма. В результате были определены параметры лазерного резонатора, при которых достигается наибольшая энергия выходного импульса Purpose. The article addresses optimization of mode-locked fiber laser based on nonlinear polarization rotation. Determination of the resonator parameters corresponding to the single-pulse with the highest energy has been performed using the genetic algorithm. Metodology. Mathematical modelling has been carried out with the help of two models, namely, scalar and hybrid. Scalar model describes signal propagation by generalized nonlinear Schr¨odinger equation. Hybrid model describes section of DCF by pair of generalized nonlinear Schrodinger equations. Numerical simulation has been performed by the split-step Fourier method. Genetic algorithm has been implemented as SteadyState method by GALib library. The value of the fitness function is equal to the energy value for the single-pulse and otherwise zero. Findings. The genetic algorithm has been implemented for solving optimization problem of fiber lasers and modifying the algorithm to reduce the calculation time. The parameters of the laser for the scalar model are determined and agreement with the results obtained by the enumeration method is presented. For the hybrid model, a stable pulse with three times the energy was found. Conclusions. In this work, a determination of the optimal parameters for mode-locked fiber lasers based on nonlinear polarization rotation was presented. The problem was solved using a genetic algorithm. This is the first step towards creating a “smart” self-tuning laser

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Shukla, P. P., and J. Lawrence. "Mathematical modelling of the fibre laser surface processing of a zirconia engineering ceramic by means of three-dimensional finite-element analysis." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 225, no. 4 (April 2011): 949–64. http://dx.doi.org/10.1243/09544062jmes2434.

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The thermal effects of fibre laser surface treatment on a ZrO2 engineering ceramic were studied using a computational finite-element model (FEM). Temperature increases on the surface and the bulk of the ZrO2 during the fibre laser processing were measured using an infra-red thermometer and specifically located thermocouples. The results showed an error of 5 per cent with the surface and 18 per cent within the bulk of the ZrO2 when comparing the experimental readings with those of the FEM. The FEM revealed a relationship between the traverse speed, power density, time, depth, and the temperature during various stages of the fibre laser surface treatment of the ZrO2. By utilizing data obtained from a thermogravimetry-differential scanning calorimetry (TG-DSC), the FEM predictions of the temperature distribution were used to map phase transformations and significant events occurring during the fibre laser surface treatment of the ZrO2. The mapping revealed that the fibre laser surface treatment generally resulted in a phase transformation of the ZrO2 at various temperatures changes as further shown in the article.

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Wickramasinghe, Sachini, Truong Do, and Phuong Tran. "FDM-Based 3D Printing of Polymer and Associated Composite: A Review on Mechanical Properties, Defects and Treatments." Polymers 12, no. 7 (July 10, 2020): 1529. http://dx.doi.org/10.3390/polym12071529.

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Fused deposition modelling (FDM) is one of the fastest-growing additive manufacturing methods used in printing fibre-reinforced composites (FRC). The performances of the resulting printed parts are limited compared to those by other manufacturing methods due to their inherent defects. Hence, the effort to develop treatment methods to overcome these drawbacks has accelerated during the past few years. The main focus of this study is to review the impact of those defects on the mechanical performance of FRC and therefore to discuss the available treatment methods to eliminate or minimize them in order to enhance the functional properties of the printed parts. As FRC is a combination of polymer matrix material and continuous or short reinforcing fibres, this review will thoroughly discuss both thermoplastic polymers and FRCs printed via FDM technology, including the effect of printing parameters such as layer thickness, infill pattern, raster angle and fibre orientation. The most common defects on printed parts, in particular, the void formation, surface roughness and poor bonding between fibre and matrix, are explored. An inclusive discussion on the effectiveness of chemical, laser, heat and ultrasound treatments to minimize these drawbacks is provided by this review.

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Cosson, Benoit. "Modelling of Laser Welding Process on Thermoplastic Composites." Key Engineering Materials 651-653 (July 2015): 1513–18. http://dx.doi.org/10.4028/www.scientific.net/kem.651-653.1513.

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Thermoplastics composites for structural applications are under growing development from the aerospace (carbon fibers with PEI, PPS or PEEK matrices mainly) to the automotive industry (glass and carbon fibers with PP, PA). The plastic deformation they can provide and the assembly facilities through welding techniques are well appreciated. Among the available welding technics, laser offers the possibility to assemble materials in a precise and localized manner and can be easily automated. However, due to the presence of continuous fibers at a high fiber volume fraction, propagation of the laser energy through the composite that present local variation of fiber volume fraction is not as straight forward as in a homogeneous material. Modelling of the laser welding of a thermoplastic/continuous glass fiber is considered here. The study takes into account the microstructure of the composite in order to evaluate changes in local energy absorption and diffusion directly linked with the thickness. Modelling of the welding process is developed from the representation of the moving laser beam. The beam propagation through the composite thickness is considered thanks to the ray tracing method. The proposed method is able to optimise the welding process in function of the microstructure and the material properties of the welded parts.

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Allan, Ewan, Craig Ballantine, Sebastian C. Robarts, David Bajek, and Richard A. McCracken. "Modelling Dispersion Compensation in a Cascaded-Fiber-Feedback Optical Parametric Oscillator." Optics 2, no. 2 (May 28, 2021): 96–102. http://dx.doi.org/10.3390/opt2020010.

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Fiber-feedback optical parametric oscillators (OPOs) incorporate intracavity fibers to provide a compact high-energy wavelength-tunable laser platform; however, dispersive effects can limit operation to the sub-picosecond regime. In this research article, we modeled pulse propagation through systems of cascaded fibers, incorporating SMF-28 and ultra-high numerical aperture (UHNA) fibers with complementary second-order dispersion coefficients. We found that the pulse duration upon exiting the fiber system is dominated by uncompensated third-order effects, with UHNA7 presenting the best opportunity to realise a cascaded-fiber-feedback OPO.

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Hu, Min, Anders Olsson, Marie Johansson, and Jan Oscarsson. "Modelling Local Bending Stiffness of Norway Spruce Sawn Timber Using Scanned Fibre Orientation." Proceedings 2, no. 8 (July 2, 2018): 505. http://dx.doi.org/10.3390/icem18-05426.

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Strength of structural timber depends to a high degree on the occurrence of knots and on the local fibre deviation around such defects. Knowledge of local fibre orientation, obtained by laser scanning, have been utilized in a previously developed machine strength grading method. However, that method was based on rather crude assumptions regarding the fibre orientation in the interior of boards and a mechanical model that does not capture the full compliance of knotty sections. The purpose of the present study was to suggest and verify a model by which local bending stiffness can be predicted with high accuracy. This study included development of a model of fibre orientation in the interior of boards, and application of a three-dimensional finite element model that is able to capture the compliance of the board. Verification included bending of boards in laboratory and application of digital image correlation to obtain strain fields comparable to those obtained by finite element simulation. Results presented comprise strain fields of boards subjected to bending and calculated bending stiffness variation along boards. Comparisons of results indicated that models suggested herein were sufficient to capture the variation of local bending stiffness along boards with very high accuracy.

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Sujecki, Slawomir. "Modelling and Design of Lanthanide Ion-Doped Chalcogenide Fiber Lasers: Progress towards the Practical Realization of the First MIR Chalcogenide Fiber Laser." Fibers 6, no. 2 (April 20, 2018): 25. http://dx.doi.org/10.3390/fib6020025.

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Stathopoulos, Nikolaos A., and Iraklis Simos. "Modelling of non-uniform and fs-Laser inscribed fibre Bragg gratings." Optical Fiber Technology 70 (May 2022): 102878. http://dx.doi.org/10.1016/j.yofte.2022.102878.

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Eydam, Agnes, Gunnar Suchaneck, and Gerald Gerlach. "Characterisation of the polarisation state of embedded piezoelectric transducers by thermal waves and thermal pulses." Journal of Sensors and Sensor Systems 5, no. 1 (May 10, 2016): 165–70. http://dx.doi.org/10.5194/jsss-5-165-2016.

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Abstract. In this work, we apply the thermal wave method and the thermal pulse method for non-destructive characterisation of the polarisation state of embedded piezoelectric transducers. Heating the sample with a square-wave modulated laser beam or a single laser pulse leads to a pyroelectric current recorded in the frequency or time domain, respectively. It carries information about the polarisation state. Analytical and numerical finite element models describe the pyroelectric response of the piezoceramic. Modelling and experimental results are compared for a simple lead–zirconate–titanate (PZT) plate, a low-temperature co-fired ceramics (LTCC)/PZT sensor and actuator, and a macro-fibre composite (MFC) actuator.

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Ali, Alaa Husein, and Raed Khalid Ibrahim. "Enhancement of single-mode optical fiber quality factor-bit error rate by using uniform fiber Bragg grating." Indonesian Journal of Electrical Engineering and Computer Science 27, no. 1 (July 1, 2022): 336. http://dx.doi.org/10.11591/ijeecs.v27.i1.pp336-346.

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The properties of optical fibers transmission systems based on Bragg gratings and uniform fibers, which are discussed in detail in this paper. Two - fiber optic communication channels Bragg gratings are used, along with Optisystem software for simulations. It is widely used in a variety of optical communication systems, such as, dispersion compensators, band filters, amplifiers and in - fiber sensors or fiber grating lasers, because of its versatility. In this design, the distance has been changed from 10 km up to 100 km, as well as the input power from 2 dBm to 16 dBm, and the calculation of both the bit error rate (BER) and quality (Q) f actor at the receiver could be studied by modelling the model of a communication system and employing the syste m's most suited settings, such as fiber cable length (km) and input power (dBm).

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Mozdy, E. J., and C. R. Pollock. "Nonlinear dynamics of the additive-pulse modelocked laser." Discrete Dynamics in Nature and Society 2, no. 2 (1998): 99–110. http://dx.doi.org/10.1155/s1026022698000089.

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We have modeled the additive-pulse modelocked (APM) laser with a set of four nonlinear difference equations, that describe the transit of optical pulses through the main cavity and through an external cavity containing a single-mode optical fiber. Simulating the system under several parameter variations, including fiber length, gain, and fiber coupling, we have observed period-doubling bifurcations into chaos. In addition, the model predicted large regimes of quasiperiodicity, and crisis transitions between different chaotic regions. We have used the method of nearest neighbors, Lyapunov exponents, and attractor reconstruction to characterize the chaotic regimes and the different types of bifurcations. We have included bandwidth-limiting and monitoring provisions to prevent non-physical solutions. To our knowledge, this is the first such characterization of chaos in the APM laser, as well as the first evidence of crisis behavior.

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Grellier, A. J. C., N. K. Zayer, and C. N. Pannell. "Heat transfer modelling in CO2 laser processing of optical fibres." Optics Communications 152, no. 4-6 (July 1998): 324–28. http://dx.doi.org/10.1016/s0030-4018(98)00164-3.

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Nguyen, Nam-Phong, Stefan Behrens, Maximilian Brosda, Alexander Olowinsky, and Arnold Gillner. "Modelling and thermal simulation of absorber-free quasi-simultaneous laser welding of transparent plastics." Welding in the World 64, no. 11 (August 25, 2020): 1939–46. http://dx.doi.org/10.1007/s40194-020-00973-5.

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Abstract The growing demands on the quality of plastic components and the trend towards miniaturisation are posing a great challenge on plastics processing technology. As many complex components can no longer be manufactured in a single step, joining processes such as laser transmission welding are gaining in importance. In classic laser transmission welding, the joining partners have different optical properties. The upper joining partner is transparent in the laser wavelength range, whilst the lower partner is absorbent due to the addition of absorber materials. In medical and biotechnological applications, the addition of absorber materials is often undesirable due to strict biocompatibility requirements. If, on the other hand, radiation sources are used which emit radiation in the area of the natural absorption of the plastic (λ = 1600–2000 nm), untreated transparent plastics can also be welded. In this work, a theoretical model will be presented to calculate the temperature distribution and progression during quasi-simultaneous welding using a thulium fibre laser (λ = 1940 nm). A sensitivity analysis is carried out to investigate the influence of different parameters on the heat affected zone (HAZ). The simulated HAZ is then compared with the HAZ from the experimental work.

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Tao, Mengmeng, Ting Yu, Zhenbao Wang, Yanlong Shen, Guobin Feng, and Xisheng Ye. "Modelling and characteristics of actively Q-switched Er-doped fibre laser with Tm-doped fibre saturable absorber." Journal of Modern Optics 64, no. 5 (October 10, 2016): 471–77. http://dx.doi.org/10.1080/09500340.2016.1242793.

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Churkin, D. V., and S. V. Smirnov. "Numerical modelling of spectral, temporal and statistical properties of Raman fiber lasers." Optics Communications 285, no. 8 (April 2012): 2154–60. http://dx.doi.org/10.1016/j.optcom.2011.12.082.

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Ignat’eva, N. Yu, O. L. Zakharkina, A. P. Sviridov, K. V. Mazaishvili, and A. B. Shekhter. "Estimation of a minimum laser power with wavelengths of 1.47, 1.56, and 1.68 μm for efficient obliteration of varicose veins." Quantum Electronics 52, no. 1 (January 1, 2022): 78–82. http://dx.doi.org/10.1070/qel17968.

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Abstract Experiments modelling endovenous laser obliteration (EVLO) are performed. As a result, laser radiation powers P c at which collagen denaturation, tissue necrosis, and vasa vasorum destruction occur throughout the entire venous-wall thickness and, at the same time, the surrounding tissues are not subjected to unnecessary heating, are found. The main criterion for determining P c is the achievement of 100 % denaturation of venous-wall proteins, confirmed by morphological and calorimetric analysis. The P c values for laser wavelengths of 1.47, 1.56, and 1.68 μm are found to be 6.0 ± 0.2, 5.0 ± 0.2, and 6.0 ± 0.2 W, respectively. It is established for all wavelengths in use that the temperature of the external venous-wall surface reaches 91 ± 2 °C at the corresponding power P c. We relate the dependence of P c on the radiation wavelength to the formation of a coagulum on the optical fibre tip moving through a blood-filled vessel. The achievement of temperature necessary for coagulum formation is determined by the simultaneously occurring processes of energy absorption and its dissipation in the form of heat. These processes become more intense with an increase in the absorption coefficient of the medium. A mechanism is proposed to explain the relationship between the P c value and laser wavelength, based on the influence of the absorption coefficient of medium (blood) on the temperature near the fibre tip.

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Meister, Sebastian, Lars Grundhöfer, Jan Stüve, and Roger M. Groves. "Imaging sensor data modelling and evaluation based on optical composite characteristics." International Journal of Advanced Manufacturing Technology 116, no. 11-12 (July 25, 2021): 3965–90. http://dx.doi.org/10.1007/s00170-021-07591-5.

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AbstractAutomated Fibre Placement is a common manufacturing technique for composite parts in the aero-space industry. Therefore, a visual part inspection is required which often covers up to 50% of the actual production time. Moreover, the inspection quality of this manual step fluctuates significantly. A camera-based automated inline inspection is capable of increasing the inspection efficiency and accuracy. However, the interpretability of the acquired data strongly depends on the sensor configuration and the inspected material. Thus, this paper introduces methods for modelling and assessing an imaging sensor on the example of a composite material reflecting a spot laser to a camera sensor. In this context, the reflection properties of the material are incorporated into a simulation and validated in comparison to real camera images from the experimental setup. The EMVA 1288 sensor model in combination with the Cramér–Rao lower bound indicates a feasible estimability of the beam propagation, but shows limitations in the predictability of the number of incident photons. The laser spot analysis indicated that the laser spot can deviate from an exact oval shape but its peak value is suitable for robust spot identification in an image. The outlined methodology is also adaptable to other imaging sensors, illumination sources and materials. Thus, the findings can be useful for other fields and manufacturing processes.

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Fu, Yuqing, and Jianguo Chen. "Theoretical modelling of dual-wavelength pumped Yb3 +–Tm3 +co-doped silica fibre laser." Journal of Optics 12, no. 9 (August 26, 2010): 095707. http://dx.doi.org/10.1088/2040-8978/12/9/095707.

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Jor, Jessica W. Y., Poul M. F. Nielsen, Martyn P. Nash, and Peter J. Hunter. "Modelling collagen fibre orientation in porcine skin based upon confocal laser scanning microscopy." Skin Research and Technology 17, no. 2 (January 17, 2011): 149–59. http://dx.doi.org/10.1111/j.1600-0846.2011.00471.x.

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Sukhanov, S. V., L. A. Melnikov, and Yu A. Mazhirina. "Numerical Modelling of a Bidirectional Long Ring Raman Fiber Laser Dynamics." Journal of Physics: Conference Series 917 (November 2017): 052010. http://dx.doi.org/10.1088/1742-6596/917/5/052010.

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Votrubec, Vlastimil. "Modelling and Simulation of Laser Welded Joints of Reinforced PP and PC Plastics." Mechanical Engineering Research 9, no. 1 (January 10, 2019): 1. http://dx.doi.org/10.5539/mer.v9n1p1.

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Welding of composites decreases their material strength. Proper evaluation of FEM simulations is necessary for correct design and safety factor determination. Neat and reinforced PP and PC specimens were measured on a testing machine to obtain their material properties. Experimental tensile curves were used as inputs in FEM simulations. 15 combinations of specimen were welded on laser work machine and afterwards the welded joint strength was measured on the testing machine. The results of shear tests and FEM simulations are compared in this paper. Also the influence of fiber presence in composites on welded joint strength is discussed. At the end suggestions for safe machinery design of laser welded reinforced composites are given.

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36

Ghoreishi, M., D. K. Y. Low, and L. Li. "Statistical modelling of laser percussion drilling for hole taper and circularity control." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 216, no. 3 (March 1, 2002): 307–19. http://dx.doi.org/10.1243/0954405021519988.

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The aim of the present work is to investigate the effects of different variables and their interactions in laser percussion drilling and to understand the possibility of controlling simultaneously the two important characteristics of a laser drilled hole: taper and circularity. Six variables, namely the peak power, pulse width, pulse frequency, number of pulses, assist gas pressure and focal plane position, were selected as independent controllable factors. The response surface method was used to statistically analyse the process. For each variable, five levels were considered and the experiments were performed based on a central composite design. A fibre-optic delivered neodymium-doped yttrium aluminium garnet laser was used to laser percussion drill mild steel sheets with a thickness of 2.5mm. The entrance diameter, the taper and the ratio of maximum to minimum Feret diameter for the hole entrance (circularity) were considered as responses/outputs in order to evaluate the process performance in terms of hole taper and circularity. Statistical modelling was carried out to develop mathematical models to relate the responses (outputs) to the six independent variables through multiple regression. A complete analysis of variance (ANOVA) was performed to test the significance of the obtained coefficients at 1, 5 and 7 per cent levels of significance. The developed models were verified by experiments. The work has shown that the pulse width and peak power have significant effects on the hole diameter, hole taper and hole circularity. However, the pulse frequency has no effect on these three hole characteristics. The number of pulses has no significant effect on hole diameter and circularity but has a significant effect on hole taper.

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Singh, Yadvinder, Jujhar Singh, Shubham Sharma, Vivek Aggarwal, and Catalin I. Pruncu. "Multi-objective Optimization of Kerf-taper and Surface-roughness Quality Characteristics for Cutting-operation On Coir and Carbon Fibre Reinforced Epoxy Hybrid Polymeric Composites During CO2-Pulsed Laser-cutting Using RSM." Lasers in Manufacturing and Materials Processing 8, no. 2 (May 24, 2021): 157–82. http://dx.doi.org/10.1007/s40516-021-00142-6.

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AbstractCurrent research focuses on optimizing various quality characteristics for kerf geometry generated through laser cutting of Coir fibre/carbon fibre/epoxy resin hybrid composite adjacent to straight cut profile employing pulsed CO2 laser system. The Kerf taper (KT) and the Surface roughness (SR) are the main quality parameters discussed. Dependent on significant process parameters, namely gas pressure, cutting speed, pulse frequency and pulse width predictive models were developed. In accordance with Taguchi's L9 orthogonal array (OA), the cutting trials are designed. Process-parametric optimization was performed using Response Surface Methodology (RSM). Furthermore, experiments were performed to obtain experimental data for the analysis of cut quality features. The impact of the input variables on the response characteristics is also explored. The morphological characterizations have been performed to analysis the effect of machining-variables and cut-quality for the top and bottom kerf widths with various laser cutting variables in the pulse laser-cutting of Coir-fibre/carbon-fibre/epoxy-resin hybrid composite. For SR and KT, the developed second order surface response model was found very successful. The optimal levels of cutting variables for KT are established at Gas pressure-6 N/mm2, pulse width-2.04 ms, cutting speed-8.01 mm/s, pulse frequency-15 Hz, for sample A1, Gas pressure-5.47 N/mm2, pulse width-2.5 ms, cutting speed-8.81 mm/s, pulse frequency-8.43 Hz, for sample A2, Gas pressure-3.85 N/mm2, pulse width-1.5 ms, cutting speed-9.06 mm/s, pulse frequency-5 Hz, for sample A3 additionally for SR Gas pressure-2 N/mm2, pulse width-1.5 ms, cutting speed-7 mm/s, pulse frequency-5 Hz, for sample A1, Gaspressure-2.36 N/mm2, pulse width-1.5 ms, cutting speed-7 mm/s, pulse frequency-15 Hz, for sample A2, Gaspressure-6 N/mm2, pulse width-1.5 ms, cutting speed-11 mm/s, pulse frequency-8.73 Hz, for sample A3. Regression results and linear and square impact of laser cutting variables have been revealed to be important to validate the model.

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Grählert, W., B. Leupolt, and V. Hopfe. "Optical modelling vs. FTIR reflectance microscopy: characterization of laser treated ceramic fibres." Vibrational Spectroscopy 19, no. 2 (April 1999): 353–59. http://dx.doi.org/10.1016/s0924-2031(99)00002-8.

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Li, Guolong, Chunyang Ma, Jie Peng, Jun Liu, Chujun Zhao, and Pinghua Tang. "Modelling the sub-100 fs Dy3+: Fluoride fiber laser beyond 3 μm." Optics & Laser Technology 158 (February 2023): 108861. http://dx.doi.org/10.1016/j.optlastec.2022.108861.

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Leone, Claudio, Silvio Genna, and Vincenzo Tagliaferri. "An integrated approach for the modelling of silicon carbide components laser milling process." International Journal of Advanced Manufacturing Technology 116, no. 7-8 (July 8, 2021): 2335–57. http://dx.doi.org/10.1007/s00170-021-07516-2.

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AbstractThe paper deals with characterisation and modelling of laser milling process on silicon carbide hard ceramic. To this end, a Yb:YAG pulsed fiber laser was adopted to mill silicon carbide bars. Square pockets, 5×5 mm2 in plane dimension, were machined at the maximum nominal average power (30W), under different laser process parameters: pulse frequency, scan speed, hatching distance, repetitions and scanning strategy. After machining, the achieved depth and the roughness parameters were measured by way of digital microscopy and 3D surface profiling, respectively. In addition, the material removal rate was calculated as the ratio between the removed volume/process time. Analysis of variance (ANOVA) was adopted to assess the effect of the process parameters on the achieved depth, the material removal rate (MRR) and roughness parameters, while response surface methodology (RSM) and artificial neuronal networks (ANNs) were adopted to model the process behaviours. Results show that both RSM and ANNs fault in MRR and RSm roughness parameters modelling. Thus, an integrated approach was developed to overcome the issue; the approach is based on the use of the RSM model to obtain a hybrid Training dataset for the ANNs. The results show that the approach can allow improvement in model accuracy.

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Huang, Jack Jia-Sheng, Yu-Heng Jan, Dawei Ren, YiChing Hsu, Ping Sung, and Emin Chou. "Defect Diffusion Model of InGaAs/InP Semiconductor Laser Degradation." Applied Physics Research 8, no. 1 (January 29, 2016): 149. http://dx.doi.org/10.5539/apr.v8n1p149.

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<p class="1Body">To enable high-performance fiber to the x (FTTx) and datacenter networks, it is important to achieve reliable and stable optical components over time. Laser diode is the essential building block of the optical components. Degradation analysis is critical for overall successful reliability design. In this paper, we study the modelling and experimental data of the InGaAs/InP laser degradation. We present a defect diffusion model that involves three propagation media (p-InGaAs contact, p-InP cladding and multi-quantum wells). We propose a simple constitutive equation based on the Gauss error function to describe the defect propagation. The physical model assumes that the p-InGaAs is the rate-limiting factor for the defect diffusion process.</p>

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Pimenov, Alexander, Shalva Amiranashvili, and Andrei G. Vladimirov. "Temporal cavity solitons in a delayed model of a dispersive cavity ring laser." Mathematical Modelling of Natural Phenomena 15 (2020): 47. http://dx.doi.org/10.1051/mmnp/2019054.

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Nonlinear localised structures appear as solitary states in systems with multistability and hysteresis. In particular, localised structures of light known as temporal cavity solitons were observed recently experimentally in driven Kerr-cavities operating in the anomalous dispersion regime when one of the two bistable spatially homogeneous steady states exhibits a modulational instability. We use a distributed delay system to study theoretically the formation of temporal cavity solitons in an optically injected ring semiconductor-based fiber laser, and propose an approach to derive reduced delay-differential equation models taking into account the dispersion of the intracavity fiber delay line. Using these equations we perform the stability and bifurcation analysis of injection-locked continuous wave states and temporal cavity solitons.

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Vesely, Jan, Daniel Hadraba, Hynek Chlup, Lukas Horny, Tomas Adamek, and Rudolf Žitný. "Constitutive Modelling and Histology of Vena saphena." Applied Mechanics and Materials 486 (December 2013): 249–54. http://dx.doi.org/10.4028/www.scientific.net/amm.486.249.

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The inflation-extension test was performed in order to obtain the mechanical response (stress-strain curves) of the human vein - vena saphena magna (usually used for coronary artery bypass graft surgery). Tubular samples of the vein were inflated four times up to the pressure approx. 4 kPa (vein pressure) and then four times up to approx. 16 kPa (systolic pressure). The experiments were recorded by the CCD camera. The longitudinal and circumferential deformations of the tube were evaluated using the edge detection method. The experimental data were fitted by anisotropic, nonlinear, constitutive model in order to obtain model parameters, especially the parameter which can be explained as collagen fibres orientation approximation. This parameter was then compared with the findings from histology. The histology analyses based on label-free imaging were performed additionally to the mechanical testing. Collagen (most important load-bearing component of the vein wall) was visualized using second harmonic generation imaging (SHG, excitation at 860 nm by a tunable IR pulse laser, detection at 430±10 nm). This method enabled us to observe collagen through the vein wall. It was found that the collagen fibres are helically aligned within the vein at an angle 37±6° measured from circumferential axis. The results of collagen orientation angle show a good agreement of findings obtained from histology and from constitutive model.

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Sujecki, S., L. Sójka, E. Bereś-Pawlik, Z. Tang, D. Furniss, A. B. Seddon, and T. M. Benson. "Modelling of a simple Dy3+ doped chalcogenide glass fibre laser for mid-infrared light generation." Optical and Quantum Electronics 42, no. 2 (January 2010): 69–79. http://dx.doi.org/10.1007/s11082-010-9421-z.

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45

Hernandez-Castaneda, Juan Carlos, Huseyin Kursad Sezer, and Lin Li. "Dual gas jet-assisted fibre laser blind cutting of dry pine wood by statistical modelling." International Journal of Advanced Manufacturing Technology 50, no. 1-4 (January 15, 2010): 195–206. http://dx.doi.org/10.1007/s00170-009-2491-z.

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46

Herthoge, Matthias, Jens De Pelsmaeker, Matthieu Boone, Ives De Baere, Wim Van Paepegem, and Sandra Van Vlierberghe. "Laser welding of carbon fibre filled polytetrafluoroethylene." Journal of Materials Processing Technology 282 (August 2020): 116681. http://dx.doi.org/10.1016/j.jmatprotec.2020.116681.

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47

Goffin, Nicholas, Lewis C. R. Jones, John Tyrer, Jinglei Ouyang, Paul Mativenga, and Elliot Woolley. "Characterisation of Laser System Power Draws in Materials Processing." Journal of Manufacturing and Materials Processing 4, no. 2 (May 19, 2020): 48. http://dx.doi.org/10.3390/jmmp4020048.

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Due to their high speed and versatility, laser processing systems are now commonplace in many industrial production lines. However, as the need to reduce the environmental impact from the manufacturing industry becomes more urgent, there is the opportunity to evaluate laser processing systems to identify opportunities to improve energy efficiencies and thus reduce their carbon footprint. While other researchers have studied laser processing, the majority of previous work on laser systems has focused on the beam–material interaction, overlooking the whole system viewpoint and the significance of support equipment. In this work, a methodical approach is taken to design a set of energy modelling terminologies and develop a structured power metering system for laser systems. A 300 W fibre laser welding system is used to demonstrate the application of the power characterization system by utilizing a purpose-built power meter. The laser is broken down according to sub-system, with each part analysed separately to give a complete overall power analysis, including all auxiliary units. The results show that the greatest opportunities for efficiency improvements lie in the auxiliary units that support the laser devices as these were responsible for a majority of the electrical draw; 63.1% when the laser was operated at 240 W, and increasing as the beam power reduced. The remaining power draw was largely apportioned to electrical supply inefficiencies. In this work, the laser device delivered a maximum of 6% of the total system power. The implications of these results on laser processing system design are then discussed as is the suitability of the characterization process for use by industry on a range of specific laser processing systems.

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Baiocco, Gabriele, Silvio Genna, Claudio Leone, and Nadia Ucciardello. "Prediction of laser drilled hole geometries from linear cutting operation by way of artificial neural networks." International Journal of Advanced Manufacturing Technology 114, no. 5-6 (April 1, 2021): 1685–95. http://dx.doi.org/10.1007/s00170-021-06857-2.

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AbstractThis paper deals on artificial intelligence (AI) application for the estimation of kerf geometry and hole diameters for laser micro-cutting and laser micro-drilling operations. To this aim laser cutting and laser drilling operation were performed on NIMONIC 263 superalloy sheet, 0.38 mm in nominal thickness, by way of a 100 W fibre laser in modulated wave regime. Linear cuts and holes (by trepanning) were performed fixing the average power at 80 W and changing the pulse duration, the cutting speed, the focus depth and the laser path (the latter only for the drilling operations). Kerf width and the holed diameter, at the upper and downsides, were measured by digital microscopy. Different artificial neural networks (ANNs) were developed and tested to predict the kerf widths and the diameters (at the upper and downside). Two ANNs were addressed to the linear cutting process modelling; also, two further ANNs were developed for micro-drilling on the base of the linear cutting process features. The networks were trained with a subset of data containing the process conditions and the kerf/hole geometry. The ANN test was performed with the remaining data. The results show that ANNs can model the cut and hole geometry as a function of the process parameters. Moreover, the ANN trained with kerf geometry is more efficient. Therefore, a functional correlation between the kerf geometries achievable in the linear cutting process and micro-drilling was assessed.

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Rowell, Eric M., Carl A. Seielstad, and Roger D. Ottmar. "Development and validation of fuel height models for terrestrial lidar – RxCADRE 2012." International Journal of Wildland Fire 25, no. 1 (2016): 38. http://dx.doi.org/10.1071/wf14170.

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Terrestrial laser scanning (TLS) was used to collect spatially continuous measurements of fuelbed characteristics across the plots and burn blocks of the 2012 RxCADRE experiments in Florida. Fuelbeds were scanned obliquely from plot/block edges at a height of 20 m above ground. Pre-fire blocks were scanned from six perspectives and four perspectives for post-fire at ~2 cm nominal spot spacing. After processing, fuel height models were developed at one meter spatial resolution in burn blocks and compared with field measurements of height. Spatial bias is also examined. The resultant fuel height data correspond closely with field measurements of height and exhibit low spatial bias. They show that field measurements of fuel height from field plots are not representative of the burn blocks as a whole. A translation of fuel height distributions to specific fuel attributes will be necessary to maximise the utility of the data for fire modelling.

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Patel, Pathik, Saurin Sheth, and Tejas Patel. "Experimental Analysis and ANN Modelling of HAZ in Laser Cutting of Glass Fibre Reinforced Plastic Composites." Procedia Technology 23 (2016): 406–13. http://dx.doi.org/10.1016/j.protcy.2016.03.044.

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Journal articles on the topic 'Modelling fibre lasers'

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