A sulfide-silicon nitride suspended waveguide capable of forward Brillouin scattering and its preparation method

Abstract

The invention belongs to the technical field of semiconductor devices, and particularly relates to a sulfide-silicon nitride suspended waveguide design capable of realizing forward Brillouin scattering and a preparation method thereof. The sulfide-silicon nitride suspended waveguide sequentially comprises a silicon substrate, a silicon oxide layer, a silicon nitride thin film layer and a sulfide thin film layer from bottom to top, wherein the silicon oxide layer below the waveguide is partially corroded to form a suspended structure. The invention provides a sulfide-silicon nitride suspended waveguide structure capable of realizing forward Brillouin scattering. The introduction of the silicon nitride structure plays a role in supporting the chalcogenide film; defects of vulcanizate softening, hanging difficulty can be overcome, meanwhile, silicon nitride is compared with sulfide, the refractive index is small, the difference of acoustic sound velocity properties is large, simultaneouslimitation of a light field and a transverse sound field is facilitated, the forward Brillouin gain coefficient obtained through simulation is 1415 m <-1 > W <-1 >, and it is proved that the structurecan be used for achieving the possibility of forward stimulated Brillouin scattering, optical machinery and other applications.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and more specifically relates to a sulfide-silicon nitride suspended waveguide capable of realizing forward Brillouin scattering and a preparation method thereof. Background technique [0002] Stimulated Brillouin scattering is widely used in microwave photonic filters, microwave signal source generation, fast light and slow light, optical storage, narrow linewidth lasers, etc., but most of the previous studies were based on the traditional backward Brillouin Abyss scattering. With the development of on-chip integrated devices, Brillouin integrated photonics has attracted more and more attention. Brillouin integrated photonics expands the realization mechanism of Brillouin scattering, especially forward Brillouin. Compared with backscattering, this scattering mechanism participates in transverse phonons, which have been applied in distributed sensing, Brillouin lasers, cavity-enhanced am...

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Problems solved by technology

[0003] At present, the material system based on on-chip forward Brillouin scattering is mainly silicon-based. By suspending the waveguide, the simultaneous localization of sound and light can be realized in the subwavelength fiber core structure, but silicon has a strong two-photon near 1550 nanometers. Absorption and free carrier absorption and other characteristics, while parameters such as Brillouin frequency shift and line width are very sensitive to the size of silicon-based devices, and changes in nanometer size will have a great impact on it, which greatly limits Achievable gain and performance of the device, so it is necessary to find other material platforms that can be used to achieve Brillouin

Sulfides are widely used in the field of backward Brillouin integration due to their excellent acousto-optic quality factor and negligible two-photon absorption, but there are no reports on forward Brillouin integration.

The key to realizing forward Brillouin scattering lies in the limitation of lateral phonons. Generally, a suspended structure is required, but the sulfide material is soft, and it is difficult to prepare a suspended structure.

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