Limitations imposed by Four-Wave Mixing (FWM), Amplified Spontaneous Emission (ASE), dispersion and Stimulated Raman Scattering (SRS) on a multi-spam DWDM system are theoretically studied. In this work, expression for the linear dispersion parameter D has been defined as a function of number of channels in order to separate FWM and SRS effects and calculates both maximum fibre length and optimum power. Additionally, our simulation results consider the effect of ASE noise from Erbium Doped Fibre Amplifiers (EDFAs). This theoretical analysis yields a set of design criteria from optimized multi-span DWDM systems.

The behavior of stimulated Brillouin scattering (SBS) and Rayleigh backscattering phenomena, which limit the forward transmission power in modern, ultra-long haul optical communication systems such as dense wavelength division multiplexing systems is analyzed via simulation and experimental investigation of threshold and maximum power. Evolution of SBS, Rayleigh scattering and forward powers are experimentally investigated with a 25 km segment of single mode fiber. Also, a simple algorithm to predict the generation of SBS is proposed where two criteria of power thresholds was used for comparison with experimental data.

This work presents an algorithm to reduce the multiplicative computational complexity in the creation of digital holograms, where an object is considered as a set of point sources using mathematical symmetry properties of both the core in the Fresnel integral and the image. The image is modeled using group theory. This algorithm has multiplicative complexity equal to zero and an additive complexity ( − 1) 2 for the case of sparse matrices or binary images, where is the number of pixels other than zero and 2 is the total of points in the image.

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We numerically analyze the temperature response of a tapered Tm 3+ -doped fiber amplifier. The analysis includes a redefinition of the coupled pump and signal propagation equations in order to introduce different longitudinal shapes of the tapered doped fiber and the temperature dependence of the absorption and emission cross sections of the Tm 3+ ions under different pump schemes. It was found that the temperature sensitivity of the normalized amplified signal was 2 × 10 −3 /°C for 1 W of pump power and 3 m of doped fiber length, using a parabolic taper in a co-propagating pump scheme. This sensitivity can be increased by at least 5 times if we adjust the design parameters of the fiber amplifier using fiber lengths shorter than 1 m and pump powers lower than 300 mW. Our results contribute with new information for the development and optimization of tapered fiber amplifiers doped with other rare earths, and novel designs for doped-fiber temperature sensors.

The evolution of the nth analytical solutions of commonly used Raman equations, analyzed by numerical simulation and experimentally, is reported. In the experiment, a 1 km undoped single-mode fiber was pumped with an ytterbium doped fiber laser system (FL) in continuous wave regime at 1064 nm in a free running configuration. We showed that it is possible to obtain up to the nth power thresholds and the maximum power for each Stokes wave by using compact analytical solutions as a first approximation in a simple, quick process. #

This work presents a comparative theoretical analysis of spatial modal evolution in micro/nano-optical fiber (MNF) tapers. The study proposes the use of the Spectral Parameter Power Series (SPPS) Method and compares its performance with results from the so-called Exact Modes Method (EMM) and the Finite Element Method (FEM) (the method employed by the COMSOL© software in which the computations were implemented). By using these techniques, the modal analysis and intensity evolution are discussed along different sections of the optical fiber taper. Furthermore, the data are compared considering experimental values from a real micro/nano-optical fiber taper sample. The SPPS method offers a competitive accuracy and versatility to deal with graded index profiles, its computational costs are low, and its implementation is relatively easy. The results from the SPPS method fit to those of the EM method, which sometimes involves intricated models, and those of the FEM, which may require more computational time. The SPPS method offers an average relative error of less than 5% with respect to the exact method with less computational cost compared to the FEM method for radii bigger than 2 μm at 1550 nm.

An all-optical microwave signal generator based on multiwavelength Brillouin-Erbium fiber laser (MBEFL) is proposed. The MBEFL unit is designed at fixed wavelength spacing of 0.084 nm, which corresponds to ~10 GHz carrier signal. The underlying mechanism MBEFL unit is by recycling the backscattered Stokes waves into the cavity to generate higher-order Stokes waves. Heterodyning process is then applied to the Brillouin pump (BP) consisted of first-order Brillouin Stokes (BS1) (0.084 nm spacing) and second-order Brillouin Stokes (BS2) (0.168 nm spacing) signals by using a photodetector (PD). The heterodyned outputs are microwave signals at the frequencies of 10.56 GHz and 21.2 GHz, relative to first order and second order Stokes waves, respectively. These microwave signals are experimentally achieved by controlling the EDF pump power where the EDF pump power can be as low as 20 mW.