Frequency enhancement and control of chaos in two spatial coupled semiconductor lasers using external light injection

Abstract

We present a novel system of oscillation frequency enhancement and control of chaos in two spatial coupled semiconductor lasers due to external light injection. We study the characteristics of frequency enhancement and control of chaos in the system and give a static frequency detuning formula. We find three regimes of chaotic enhancement when external light is injected into single laser, in which, strong light injection can result effectively in frequency enhancement in the injected laser, but the frequency weakens slowly in the other. And large detuning can result effectively in frequency enhancements in both lasers while the frequency can be enlarged 3.5 times more than the intrinsic frequency of the laser 1. Chaos-control region is found in low injection levels. In this region, lasers can be controlled to single -cycle, dual-cycle, cycle-4, cycle-6 and other quasi-cycles. When the dual-injection is present, strong light injection or large detuning can result effectively in frequency enhancements in both lasers while the frequency can be enlarged 3.5 or 2.65 times more than the intrinsic frequency of the laser 1 or 2. Chaos-control region is also found in large injection levels. In this region, both lasers can be controlled to single-cycle, cycle-3, cycle-6 and other quasi-cycles. We point out in detail a path from single-cycle to quasi-cycle to frequency enhancement of chaos when the single-injection is present. We find another reverse path from chaos to quasi-cycle to single-cycle when the dual-injection is present.