Tailoring Spectral Properties of Binary PT-Symmetric Gratings by Duty-Cycle Methods

We explore the frequency selective functionalities of a nonuniform PT-symmetric Bragg grating with modulated complex index profile. We start by assessing the possibility to achieve an efficient apodization of the PT-symmetric Bragg grating spectral response by using direct adaptations of the conventional apodization techniques. A particular emphasis is put on the binary type structures with different duty cycle variations. We subsequently propose a new efficient grating modulation technique allowing for largely improved reflection/transmission characteristics of the Bragg gratings. The overall intention of our approach is to adapt conventional Bragg gratings designs to improve a PT-symmetric case, fostering thus a new generation of active photonic devices.