Active influence of optical modes in film waveguides based on As-S system


Introduction. The recovery response characteristics of optical stopping-effect on the AsxS100-x system (20≤x≤40) film waveguides are investigated in detail. We analyzed the chemical bond structure of the samples. The hybrid orbital theory and energy bandgap theory are applied in order to establish the model of optical stopping and the recovery process.
Purpose. Amorphous semiconductor chalcogenides are potentially useful materials for integrated nonlinear optical components offering low-phonon energies, ultra-fast broadband optical response times. These unique optical properties make them very interesting for integrated optical devices and all-optical signal processing. The article is devoted to consideration of usage As-S films as an active element of waveguide attenuators.
Results. AsxS100-x thin-film waveguides demonstrated the slow recovery propagation process with the disappearance of the fast rising edge in the optical stopping-effect. It is shown that in the propagation channel of waveguide modes there is a competition between two processes of changes in optical losses (the fast creation of an external optical recording from the initiating irradiation and its optical erasure by a controlling optical mode). The slow process taking several seconds for full recovery, moreover meaning that the actions of the photon pumping and thermal disturbance are equal and opposite in direction. The time parameters of processes essentially depended on the composition of the films, on the flux density of the initiating external radiation and on the control mode in the film waveguide. We have established that the time constants for dynamic changes in the refractive index under external illumination are weakly correlated with similar characteristics of the stopping-effect.
Conclusion. The article is devoted to consideration of usage As-S films as an active, and it was confirmed that the device exhibits useful switching functionality based on the photo-optical effect (light-controlled waveguide optical attenuators)

Keywords: optical recording, integrated optics, amorphous chalcogenides, thin-film waveguide, optical waveguide technology, propagation loss