Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 31 for “"Self-Phase Modulation"”.
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All-optical 2r regenerator based on self-phase modulation
… All-Optical 2R Regeneration which is based on self-phase modulation (SPM) in a single highly nonlinear fiber (HNLF) with 2500 km length of transmission is investigated. In addition, there are two types of modulation format namely, non-return�to-zero on-off keying (NRZ-OOK) and return-to-zero …
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Femtosecond Pulse Compression via Self-Phase Modulation in 1-Decanol
… generated using spectral broadening via self-phase modulation, followed by dispersion compensation. The most common spectral broadening technique exploits the nonlinear interaction of intense pulses focused into gas-filled hollow-core fibres. More recently, multiple crystal plates have …
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High-order compensation of self-phase modulation in laser communication systems
Self-phase modulation (SPM) creates a power and fiber-length dependent spectral broadening that reduces signal-to-noise ratio in free-space laser communication systems which use a fiber to connect their transmitter's high-power optical amplifier to its telescope optics. The effects of SPM can be …
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A preconditioned Newton-Krylov method for computing steady-state pulse solutions of mode-locked lasers
… of any nonlinear optical cavity with moderate self phase modulation, such as those of solid state lasers, and requires only a model for the round-trip action of the cavity. We conclude by proposing avenues of future work to improve the method's convergence and expand its applicability to lasers …
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A circuit model BOSS simulation of nonlinear effects in long distance fiber optic systems
… may occur. The nonlinearity considered here is self-phase modulation (SPM). A loop system is designed where each pass of the system corresponds to 200 km of fiber. The system mainly consists of a Butterworth bandpass filter which models the dispersion in the fiber and a VCO that imposes a phase …
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Dispersion-managed Breathing-mode Semiconductor Mode-locked Ring Laser
… to minimize the detrimental strong integrating self-phase modulation and to enable efficient pulse amplification. Subsequently compressed pulses facilitate bleaching the semiconductor saturable absorber. The intracavity pulse compression ratio is higher than 50. Down chirping when compared to up …
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The generation of high field terahertz radiation and its application in terahertz nonlinear spectroscopy
… in cooled LN where THz intensity-dependent self-phase modulation and harmonic generation were observed. An outlook and preliminary results toward implementation and observation of high-field THz-driven responses in ferroelectric materials are given in the final chapter of this thesis.
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Measurement of the nonlinear refractive index (n2) and stimulated Raman scattering in optical fibers as a function of germania content, using the photorefractive beam coupling technique
… length of an optical fiber, where it undergoes self-phase modulation (SPM) and other nonlinear distortions, and the output pulse is split into two. The two-excitation pulses are then coupled into a photorefractive crystal, where they interfere and form a photorefractive phase grating. The IGA …
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Distributed optical-fibre sensors for monitoring mechanical strain and disturbance
… the need to prevent spectral broadening due to self-phase modulation, which adds noise to the sensor output. <br/><br/>Applying the findings of these investigations, further field trials and laboratory tests were carried out with improved experimental C-OTDR sensors. By optimising the pulse …
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Ultrafast Transient Absorption and Multi-Wave Mixing Spectroscopies in the Extreme Ultraviolet and Soft X-RAY Regimes
… and pulse compression techniques such as self-phase modulation in hollow-core fibers and chirped-mirror dispersion compensation. We showcase the application of such novel ultrafast pulses in probing dark state dynamics with femtosecond temporal resolution in a novel three-color wave mixing …
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Multi slot amplitude coding technique for high speed optical fiber communication system
… performance of MSAC technique is simulated under self phase modulation (SPM) effect. The result shows that the maximum launched optical power is +12.79 dBm and +12.62 dBm for 50 km and 80 km standard single mode fiber (SSMF) with 100% compensation of dispersion using dispersion compensation fiber …
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Ultrashort, High Power, And Ultralow Noise Mode-locked Optical Pulse Generation Using Quantum-dot Semiconductor Lasers
… measured for the first time. The role of the self-phase modulation and the linewidth enhancement factor in QD mode-locked lasers is addressed. The noise performance of two-section mode-locked lasers and a SOA-based ring laser was investigated. Significant reduction of the timing jitter under …
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Development and applications of dispersion controlled high nonlinearity microstructured fibres
… at 1.06 μm, the nonlinear effects such as Self-Phase-Modulation, Four-Wave-Mixing and Self-Soliton-Frequency-Shift, which dominate the spectral broadening in fibres with one or two zero-dispersion wavelengths are identified accordingly.<br/><br/>The latest work has been focussed on …
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Theory of optical rectification in a travelling wave structure
… polarization optical modes in the structure. The self phase modulation due to cascading of OR and the electro-optic effect is elucidated. It is shown that continuous wave solutions of the conservative system are modulationally unstable in a large range of relevant system parameters. The …
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High speed optical communication systems: From modulation formats to radically new fibres
… [1,2]. It is in this context that the work on modulation formats, contained in Chapter 3 of this thesis, was undertaken. The work investigates the proposed energy-efficient four-dimensional modulation formats. The work begins by studying a new visualisation technique for four dimensional …
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HIGH POWER PULSED FIBER LASER SOURCES AND THEIR USE IN TERAHERTZ GENERATION
… scattering, stimulated Brullion scattering, and self-phase modulation. The thresholds for these nonlinearities scale inversely with intensity and length. Thus, we used a short phosphate fiber gain stage to reduce the length, and a large core fiber final stage to reduce intensity. In this way we …
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Theory of terahertz generation by optical rectification
… radiation in two spatial dimensions (2-D), (iii) self-phase modulation, (iv) stimulated Raman scattering and (v) crystal geometry. The key finding is that THz generation necessarily leads to broadening of the optical pump spectrum, resulting in a rapid spatio-temporal break-up of the pulse which …
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Intensyvių femtosekundinių šviesos bangų paketų sklidimo Kero terpėse laikinis ir erdvinis charakterizavimas /
In the disertation, the self-focusing phenomenon of intense femtosecond light pulses in media with cubic nonlinearity is investigated and the origin of formation of light filaments is revealed. In this work, new measurement techniques are introduced and applied experimentally, which allowed high …
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Characterising nonlinear waveguides by scanning near-field optical microscopy
… the interference of various modes with different phase modulation owing to dispersion and nonlinear effects. Accordingly, the complexity of the spectral features increase with the propagation distance and the number of contributing modes. The multimode spectra rapidly broaden at the beginning …
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Nonlinear Optics in III-V Quaternary Semiconductor Waveguides
… strip-loaded waveguides. We have performed self-phase modulation, nonlinear absorption measurements, and four-wave mixing experiments at the telecom wavelength range. The nonlinear phase shift up to 2.5 $\pi$ has been observed. Following that, we use Monte-Carlo method for design …
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