Transverse traveling pulses in bistable interferometers with competing nonlinearities

Regenerative pulsations in semiconductor etalon due to competition between carrier generation and heating effects on band filling

“…We assume these conditions are met. Moreover, in this article we restrict ourselves by considering only the homogeneous distributions also in the plane of the semiconductor layer, leaving the transversal effects 4,5 to an additional study. Then, the description of the semiconductor etalon is reduced to the following two rate equations:…”

“…Note that a considerable difference in the relaxation rates of the competing ONs, resulting in a splitting of the fast and slow stages in the dynamics of the nonlinear system, is a general condition for a discussed kind of regenerative pulsations. [1][2][3][4][5][6][7][8][9] In the fast stage, the response of the semiconductor etalon is determined only by the effective electron temperature T e which, computed as a function of the intensity of the incident light, I i , is shown in Fig. 3͑a͒.…”

“…1 Although this is quite a common phenomenon, not restricted by any particular type of device nor mechanism of ON, most foregoing studies, [2][3][4][5][6][7] including ours, [4][5][6][7] refer to a semiconductor etalon with electronic and thermal dispersive nonlinearities. In that case, carrier concentration, due to band filling in a narrow band gap semiconductor like InSb [3][4][5][6][7] or weakening of free-exciton resonance in a wide band gap semiconductor like GaAs, 2 and lattice temperature both effect the near absorption edge refractive index, but in opposite manners. The former plays the role of the fast variable responsible for optical bistability, while slow variation of the latter prevents either state from being stable, that ultimately results in the regenerative oscillations.…”