Escola de Engenharia Mackenzie (EE)

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https://dspace.mackenzie.br/handle/10899/36

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Navegando Escola de Engenharia Mackenzie (EE) por Autor "Aiub, Eduardo José"

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    Dissertação
    Dissulfeto de molibdênio esfoliado micromecanicamente depositado em fibra óptica para geração de pulsos ultracurtos
    Aiub, Eduardo José (2016-08-01)

    Escola de Engenharia Mackenzie (EE)

    In this work, we describe the characterization, transfer process and fabrication of mechanically exfoliated MoS2 (molybdenum disulfide) samples deposited on the fiber facet and D-shaped fiber. The characterization of these samples was made through Raman spectroscopy, making a mapping of the samples and analyzing the frequency difference between the vibrational modes E2g e A1g, it is possible to determine the number of layers to be transferred. Also, it was required to prepare a layered substrate of PVA (polyvinyl alcohol) and PMMA (Polymethyl- methacrylate), so that it was possible to remove the nanomaterial from the glass substrate and deposit it on another surface. Furthermore, it was performed control and alignment of the material with the core of the fiber, using a stage XYZ and an optical microscope (10X lens). An application for the fabricated samples was demonstrated through the generation of ultrashort pulses in EDFL (Erbium-doped fiber lasers) and YDFL (Ytterbium-doped fiber lasers) using them as saturable absorbers. The best results obtained were a pulse duration of 810 femtoseconds and bandwidth of 4.09 nm using mechanically exfoliated MoS2 on the fiber facet and pulse duration of 200 fs and bandwidth of 20,5 nm on the D-shaped fiber. In the samples on the fiber facet was the presence of NPR (Nonlinear Polarization Rotation) resulting in a hybrid effect. Results of ultrashort pulses with mechanically exfoliated MoS2 have not yet been reported in the literature.
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    Tese
    Geração de pulsos ultracurtos com acoplamento de modos híbrido em um laser de fibras ópticas mantenedoras de polarização
    Aiub, Eduardo José (2020-08-17)

    Escola de Engenharia Mackenzie (EE)

    A main motivation for this doctoral thesis was the recent use of lasers with ultrashort pulses being used in ultra-fast optical transmission systems (above 1 Tbit/s). For this, ultrashort pulse generation was demonstrated in two different lasers, one with SMF fibers for the ultrashort pulses generation using the hybrid mode-locking technique and the other with all components and fibers polarization maintaining (all-PM) for short pulses in Q-Switching Mode Locking regime. In the SMF laser, operating in hybrid mode-locking,the main innovation of the work was the use of two-dimensional materials as a saturable absorber at a repetition rate of 40 GHz, using two samples of CVD graphene and one of molybdenum disulfide. The results obtained were pulses with a duration of 655 and 620 fs with CVD graphene and 425 fs with MoS2. It is worth mentioning that, these results contribute to the state of the art as the first measurements of ultrashort pulses using 2D materials at a repetition rate of 40 GHz. In the all-PM laser, which was built to minimize laser instability and separate the possible presence of non-linear polarization rotation (NPR) existing in laser results with standard fibers,the main innovation was the use of CVD graphene deposited on D-shaped PM fiber and as a result, short pulses were obtained for the first time in Q-Switching regime. The challenge of this work was to build a laser capable of operating at a repetition rate of 40 GHz using two-dimensional materials as a saturable absorber and the construction of an all-PM laser for better stability