Silicon nitride grating coupler, preparation method thereof and optical device

Abstract

The invention discloses a silicon nitride grating coupler, a preparation method thereof and an optical device, relates to the technical field of optical devices, and aims to provide a technical scheme for effectively improving the coupling efficiency of an optical fiber and an optical chip in a mode of combining a low-pressure chemical vapor deposition method and plasma enhanced chemical vapor deposition. The silicon nitride grating coupler comprises a substrate; a cladding layer formed on the substrate; a grating coupler formed in the cladding; wherein the grating coupler comprises a first silicon nitride grating coupling layer and a second silicon nitride grating coupling layer which are arranged at an interval from bottom to top, and a cladding is formed between the first silicon nitride grating coupling layer and the second silicon nitride grating coupling layer; wherein the first silicon nitride grating coupling layer is formed by adopting a low-pressure chemical vapor deposition method, and the second silicon nitride grating coupling layer is formed by adopting a plasma enhanced chemical vapor deposition method.

Description

technical field [0001] The invention relates to the technical field of optical devices, in particular to a silicon nitride grating coupler, a preparation method thereof, and an optical device. Background technique [0002] Since silicon nitride has the advantages of low loss and high nonlinearity, it is considered to be one of the ideal core materials for waveguide devices. [0003] Although the silicon nitride film deposited by LPCVD has good quality and low waveguide loss, but the film stress is large, it cannot be deposited very thick, and it is prone to cracks; but the silicon nitride film deposited by PECVD can deposit very thick films, but the waveguide The loss is large. Therefore, LPCVD is often used to prepare silicon nitride with a thickness of 100nm or 200nm as the core layer of the device. The refractive index difference is small, the coupling efficiency of the grating coupler is very low, and the loss of the optical signal from the optical fiber to the optical...

AI Technical Summary

Problems solved by technology

[0003] Although the silicon nitride film deposited by LPCVD has good quality and low waveguide loss, but the film stress is large, it cannot be deposited very thick, and it is prone to cracks; but the silicon nitride film deposited by PECVD can deposit very thick films, but the waveguide Greater loss

Therefore, LPCVD is often used to prepare silicon nitride with a thickness of 100nm or 200nm as the core layer of the device. The refractive index difference is small, the coupling efficiency of the grating coupler is very low, and the loss of the optical signal from the optical fiber to the optical chip is too large, which cannot meet the actual application requirements.

Images