957 research outputs found
Dataset for Frequency-banded nonlinear Schrödinger equation with inclusion of Raman nonlinearity
No full textThis repository holds the data published in the paper:
Begleris, I., & Horak, P. (2018). Frequency-banded nonlinear Schrödinger equation with inclusion of Raman nonlinearity. Optics Express, 26(14).
The data is proof of the argument of the viability and efficiency of the Banded nonlinear Schrödinger equation against the Generalised nonlinear Schrödinger equation.</span
Dataset for "Efficiency and intensity noise of an all-fiber optical parametric oscillator"
No full textDataset for article "Efficiency and intensity noise of an all-fiber optical parametric oscillator" by I. Begleris and P. Horak, accepted for publication in Journal of the Optical Society of America B (2019)
The set contains all the raw data generated by computer simulations that are analysed and plotted in the paper.</span
Multimodal simulations of fibre optical parametric amplifiers and oscillators
No full textSystems that are capable of converting light between frequencies are attractive since they can produce output at wavelengths other than those provided by conventional laser sources. These wavelength conversion devices can then be utilised in a variety of applications that require light at unconventional frequencies. Such systems are also useful in the telecommunications industry to convert energy between channels within wavelength division multiplexing fibre systems. Furthermore, since the channels of fibres used within telecommunications are being increased by using multi-mode fibres, mechanisms that can convert energy between these modes are also favourable. To seamlessly apply these converters to the telecommunications fibre network and to maintain the advantages that fibres provide it is preferable for the energy conversions to occur within optical fibres. Fibre optical parametric amplifiers are all-fibre optical systems where the nonlinearity of the materials is utilised for energy conversion between wavelengths and fibre modes. The conversion efficiency of these devices can however be reduced by non-uniformities of parameters along the propagation direction. This adverse effect can though be controlled by enhancing the amplifier system into a fibre optical parametric oscillator. Fibre based amplifiers and oscillators whose purpose is to convert energy between wavelengths and fibre modes are investigated throughout this thesis. The wavelength and mode conversion within these amplifiers and oscillators occurs when light is transmitted through an optical fibre. Pulse propagation through these devices is numerically simulated throughout this study by using the multi-mode generalised nonlinear Schrödinger equation. This model is therefore used to investigate wavelength and mode conversion. Furthermore, the frequency banded generalised nonlinear Schrödinger equation is derived and validated as part of this study. This equation allows the effective and accurate simulation of wavelength conversion over ultra-large bandwidths. Numerical methods that describe the fibre optical parametric amplifiers and oscillators are detailed throughout this thesis. These highly optimised models are then simulated over a multitude of parameters to calculate the efficiency and noise of the parametric systems. Initially, mode conversion using a multi-mode fibre optical parametric amplifier is investigated. Attention is then drawn upon the operation and inner workings of a single-mode fibre optical parametric oscillator. Finally, the research study culminates with the, to the best of the author's knowledge, first investigation into a multi-mode fibre optical parametric oscillator whose purpose is to convert energy between modes
Stability of a fiber optical parametric oscillator with and without a seed signal
No full textWe present a numerical model of a unidirectional fiber optical parametric oscillator. Power fluctuations between signal round-trips are investigated and found to be significant. Finally, the option of seeding the signal wave is discusse
Efficiency and intensity noise of an all-fiber optical parametric oscillator
No full textAn all-fiber optical parametric oscillator comprising a highly nonlinear optical fiber and wavelength division multiplexing couplers is numerically simulated. The model is based on a set of coupled nonlinear Schrödinger equations which spectrally resolve the gain bandwidth of the pump, signal and idler waves. We show that such high wavelength resolution is necessary to obtain the correct threshold pump powers, stationary output powers, and relative intensity noise. Finally, we compare seeded and unseeded configurations and find that the seeded configuration generates low-noise idler output at conversion efficiencies of up to 10% below the threshold power for unseeded operation, but that both seeded and unseeded oscillators produce comparable results above threshold
Multi-band nonlinear Schrödinger equation for efficient simulation of parametric optical amplifiers and oscillators
No full textFrequency-banded nonlinear Schrödinger equation with inclusion of Raman nonlinearity
No full textThe well-established generalized nonlinear Schrödinger equation (GNLSE) to simulate nonlinear pulse propagation in optical fibers and waveguides becomes inefficient if only narrow spectral bands are occupied that are widely separated in frequency/wavelength, for example in parametric amplifiers. Here we present a solution to this in the form of a coupled frequency-banded nonlinear Schrödinger equation (BNLSE) that only simulates selected narrow frequency bands while still including all dispersive and nonlinear effects, in particular the inter-band Raman and Kerr nonlinearities. This allows for high accuracy spectral resolution in regions of interest while omitting spectral ranges between the selected frequency bands, thus providing an efficient and accurate way for simulating the nonlinear interaction of pulses at widely different carrier frequencies. We derive and test our BNLSE by comparison with the GNLSE. We finally demonstrate the accuracy of the BNLSE and compare the computational execution times for the different models
Inter-modal four wave mixing study in a two-mode fiber
No full textThis data set holds the data used to plot the figures presented in the paper S. M. M. Friis, I. Begleris, Y. Jung, K. Rottwitt, P. Petropoulos, D. J. Richardson, P. Horak, and F. Parmigiani, "Inter-modal four-wave mixing study in a two-mode fiber," Opt. Express 24, 30338-30349 (2016) DOI:10.1364/OE.24.030338</span
Conversion efficiency and bandwidth of inter-modal four wave mixing in two-mode optical fibres
No full textFWM is a non-linear process where two or more wave propagating throughout a fibre result in a production of frequencies different to that of the input waves. Space division multiplexing and in particular mode division multiplexing (MDM) have shown promises in overcoming the capacity limit of single-mode fibres for optical telecommunications. Over long distances MDM systems would result in processes like inter modal FWM (IM-FWM). If such systems are to be used commercially, they will require methods of switching data signals between wavelengths and spatial modes. An attractive solution is provided by four-wave mixing (FWM) where two strong pump fields convert the signal into an idler field at another wavelength. However, applications of intermodal FWM (IM-FWM) for telecommunications in multimode fibres are relatively new. Recently, two potentially interesting IM-FWM processes have been identified: phase conjugation (PC) and Bragg scattering (BS) [Essiambre et al., IEEE Photon. Technol. Lett. 25, 539 (2013)].Here we investigate conversion efficiencies and spectral bandwidths of PC and BS in a two-mode optical fibre as potential mode/wavelength conversion systems using two numerical models and compare with experimental results.The first model uses the coupled amplitude equations for FWM [Agrawal, Nonlinear fiber optics, Academic Press (2013)] which take into account self and cross phase modulation and FWM between the four wavelength channels involved. This model was found to agree with experimental results of the PC idler. However discrepancies are found for BS, which we attribute to simultaneous and/or cascaded FWM processes within the same fibre. Thus we use a second, more sophisticated model, the multimode nonlinear Schrödinger equation [Poletti & Horak, JOSAB 25, 1645 (2008)] which, contrary to the first model, includes all third order nonlinear processes simultaneously and is additionally able to predict cascaded FWM processes that occur throughout the spectrum. We compare the differences between the two models, analyse the contributions to the BS and PC idlers from multiple FWM processes within the spectrum, and finally present comparisons to experimental results
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