Stability of incoherently coupled bright-dark spatial soliton pairs in biased two-photon photovoltaic photorefractive crystals

摘要

This paper investigated numerically the stability of bright-dark soliton pairs in biased two-photon photovoltaic photorefractive crystals. Our analysis indicates that these soliton pairs exist irrespective of the polarity of photovoltaic field and external bias field and they are stable only in the particular range of negative polarity. That is to say, the modulational instability emerges for the positive polarity. In range of negative polarity, there exist a characteristic value of photovoltaic field and external bias field. When the values are less than the characteristic value, these bright-dark soliton pairs are stable. If the values are large than the characteristic value, the modulational instability will still emerge.