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A theoretical study of the dynamics of short high-concentration gain-clamped Er3+-Yb3+ codoped fiber amplifiers is presented. The effect of various parameters on the transient power excursions and relaxation oscillation frequency of a given signal input channel when other signal channels are added or dropped from an initial steady-state configuration is analyzed. In particular, the effects of Er3+ clustering, Yb3+ concentration, fiber length, lasing wavelength, pump wavelength, pump power, and cavity losses are shown. The numerical results demonstrate the importance of Yb3+ sensitization in achieving stable gain-clamped operation in a range of operating conditions. It is shown that the amplitude of power excursions is typically small, e.g., less than 0.1 dB, provided that the amount of Er3+ ions in the clusters is kept small. [ABSTRACT FROM PUBLISHER]

High-power continuous-wave Nd3+-Yb3+ codoped fiber lasers (NYDFL) are analyzed, based on a rate-propagation equations model. The model takes into account energy transfer between Nd3+ and Yb3+, as well as cross relaxation between Nd3+ ions, and contributions from high-order modes to the amplified spontaneous emission (ASE). Examples of cladding-pumped NYDFLs with distributed Bragg reflector (DBR) at either end are presented. We demonstrate the optimal laser design by considering the effects of the Nd3+ and Yb3+ concentrations, pump wavelengths multiplexing, output mirror reflectivity, and the laser wavelength. Approximate quasi-analytical solutions are shown to be in good agreement with the exact numerical solutions of the rate equations for practical conditions [ABSTRACT FROM PUBLISHER]

We present combined experimental and theoretical investigations of the picosecond emission dynamics of broad-area semiconductor lasers (BALs). We enhance the weak longitudinal self-mode-locking that is inherent to BALs by injecting a single optical 50-ps pulse, which triggers the output of a distinct regular train of 13-ps pulses. Modeling based on multimode Maxwell-Bloch equations illustrates how the dynamic interaction of the injected pulse with the internal laser field efficiently couples the longitudinal modes and synchronizes the output across the laser stripe. Thus, our results reveal insight into the complex interplay between lateral and longitudinal dynamics in BALs, at the same time indicating their potential for short optical pulse generation. [ABSTRACT FROM PUBLISHER]

A theoretical investigation of the high-speed coupling phenomena of two laterally coupled diode lasers (LCDL) is presented. The analysis is centered on the spatiotemporal dynamics of the LCDL when coupling between emitters is varied, We have obtained the dynamic behavior of these devices showing high resonance frequencies beyond the well-known resonance frequency of a single diode laser. In this paper, we have presented a new modulation scheme by asymmetric switching of the injected current in both stripes, showing short optical output pulse modulation with a high repetition rate [ABSTRACT FROM PUBLISHER]

Analyzes the modeling of the performance of high-power semiconductor laser systems with an optothermal microscopic spatio-temporal theory. Interaction between the optical fields, the charge carriers and the interband polarization; Microscopic and macroscopic dynamics of the systems; Fundamental material and device parameters of the broad-area semiconductor lasers.

We study pulse propagation in Er3+-doped fiber amplifiers (EDFA) within the framework of a spectrally resolved pulse rate-propagation equations model. Our model accounts for the effects of gain dispersion, gain saturation, waveguide and chromatic dispersion, and amplified spontaneous emission. This model allows us to approximate the effects of nonlinear resonant dispersion on short pulse amplification in doped fibers, without reverting to the generalized nonlinear Schroedinger equation. Numerical results of the time-dependent power spectrum of the amplified pulse demonstrate subpicosecond pulse propagation in EDFAs [ABSTRACT FROM PUBLISHER]

A robust methodology is presented for the accurate modal analysis of three-dimensional dielectric waveguides with the finite-difference time-domain (FDTD) method. We investigate the propagation of well-defined vector modes along strongly guiding rectangular waveguides. Eigensolutions of the vectorial wave equation are utilized in the simulations to accurately launch the fundamental and higher order eigenmodes. Results for their FDTD-computed propagation constant are found to be in excellent agreement with existing mode-solving techniques. Improved accuracy or significant computational savings are achieved when the nonstandard FDTD concepts are incorporated in the context of the present analysis. [ABSTRACT FROM PUBLISHER]