DOI: 10.1117/12.921949 Conference: Proc. of SPIE, Volume: 8432
In this paper, we have theoretically studied the dynamical behavior of current modulated semiconductor ring lasers (SRLs). As we vary the amplitude and frequency of the modulation around a fixed bias current, different dynamical states including periodic, quasi-periodic and chaotic states are found. As in other single mode semiconductor lasers, the modal intensities in a SRL present chaotic behavior for driving frequencies comparable to the relaxation oscillation frequency. In this regime the two counter-propagating modes vary in phase. However, for modulation frequencies significantly lower than the relaxation oscillation frequency, we reveal the existence of chaotic oscillations where the two counter-propagating modes are in anti-phase. In order to get a more complete understanding of the dynamics of SRLs at low modulation frequencies, we derive a reduced model using asymptotic methods. This reduced model uncovers a topological resemblance between current-modulated SRLs and the periodically driven Duffing-Van der Pol oscillator.
[Show abstract][Hide abstract] ABSTRACT: The electric field of the modes of semiconductor microring lasers (SMRLs) in the presence of bus waveguide reflections are linear combinations of the clock wise (CW) and the counter clock wise (CCW) electric fields. The mode structures can be controlled by the waveguide reflection coefficients. The power ratio and phase difference of the CW and CCW fields of one mode is proportional to the ratio of the reflection coefficients of the left and right waveguides. It is shown that the degenerate CW and CCW modes in the presence of bus waveguide reflections are split into two modes with different frequencies. Employing these new modes, SMRL can be used as an element to design flip-flops used in photonic integrated circuits. For a symmetric structure, the inter-frequencies of CW and CCW waves relating to each mode can be considered as the output of the optical flip-flop. Output of asymmetric mode is zero while the symmetric mode has a nonzero output.
[Show abstract][Hide abstract] ABSTRACT: In order to understand and explain recently reported nonlinear behaviors in semiconductor ring lasers (SRLs) and to further design novel functional devices, a multimode model has been developed for linear and nonlinear interactions between modes in an SRL lasing unidirectionally. The model includes population pulsation, spectral hole burning, carrier heating, and four-wave mixing effects. Heterodyne detection has been used to make high-resolution measurements of the lasing spectra of an SRL in which the individual resonances associated with the coupled eigenvalues can be observed. By fitting these high-resolution spectra to the model, we have extracted a number of key parameters characterizing the coupling mechanisms in the device and the semiconductor gain medium. Using these parameters, the model generates device characteristics in very good agreement with experimental results, which validate its use for future device design and optimization.
[Show abstract][Hide abstract] ABSTRACT: We study the nonlinear dynamics of ultra-high frequency current-modulated semiconductor lasers. A retroactive coupling scheme is applied to achieve their synchronization both in the regular and chaotic regimes. The stability analysis is performed to determine the suitable coupling parameters leading to high-quality synchronization. The consequences of parameter mismatch are also highlighted. Numerical simulations confirm the analytic approach.
Physics Letters A 03/2003; 308(5-6-308):381-390. DOI:10.1016/S0375-9601(03)00070-7 · 1.68 Impact Factor
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