Separate coupled solitons in biased series photorefractive semiconductor circuit

We present, for the first time a theoretical foundation for separately coupled solitons in a biased series circuit consisting of semi-insulating photorefractive multiple quantum well (MQW) waveguides. As an example, a slab semiconductor waveguide based on a GaAs/AlGaAs structure is considered. The coupled steady state space charge field is derived for both the MQW structures using a bipolar band transport model. Hence, a system of two coupled equations is obtained for each MQW structure which governs the dynamical evolution of light beams. We then prove the existence of dark–dark, grey–grey and grey–dark separately coupled soliton pairs. We also see that the soliton propagating individually in one PR semiconductor can affect the other by the light-induced current. We investigate this coupling effect with respect to the soliton beam's intensity profile and for each of the three cases, namely, dark–dark, grey–grey and grey–dark separately coupled solitons. Some potential applications are discussed.