Characteristics of self-switching of unidirectional distributively coupled waves with orthogonal polarisations

A general solution of the problem of the interaction between unidirectional distributively coupled waves with orthogonal polarisations is found an analysed. Interesting features of optical self-switching of these waves are identified and key formulas describing such switching are derived. It is shown that signal amplification as a result of self-switching may be extremely high and this can happen even when the coupling coefficient is zero. This case of zero coefficient is paradoxically of the greatest practical interest. The results obtained should be useful in working with birefringent waveguides and crystals.