Using optical PT-symmetry for switching applications

• This work introduces a new class of PT-symmetry grating assisted devices for switching or modulation applications. Their operation is based on a four-wave interaction, thus marking a step in the further development of PT-symmetry devices which currently are essentially based on two-wave interactions.
• A very interesting aspect of our approach is that all the described behavior and properties also hold for the case of imperfect PT-symmetry operation, corresponding to the important practical case of fixed losses. Switching or add-drop operations are achieved from the sole gain variation, which is much more convenient for practical applications.

This work introduces a new class of PT-symmetry grating assisted devices for switching or modulation applications. Their operation is based on a four-wave interaction, thus marking a step forward in the development of PT-symmetry devices which currently are essentially based on two-wave interactions. A remarkable feature of the new structure is that all its properties also hold in the case of imperfect PT-symmetry operation, corresponding to the important practical case of fixed losses.