A coupling structure between an optical fiber and a high-refractive-index waveguide

Abstract

The invention discloses a coupled structure between an optical fiber and a high refractive index waveguide and relates to the field of optical communication device, the coupled structure between the optical fiber and the high refractive index waveguide comprises a back taper coupler, a graded waveguide and a straight waveguide, the wide end of the graded waveguide aims at the optical fiber while the narrow end thereof is connected to the straight waveguide, the back taper coupler is formed in the straight waveguide, the part close to the optical fiber of the graded waveguide is covered in the first matching liquid, the part close to the back taper coupler of the graded waveguide and the straight waveguide are covered in the second matching liquid, the part between the first matching liquid and the second matching liquid of the graded waveguide is totally covered in the transition matching liquid, the refractive index of the first matching liquid is n1, the refractive index of the second matching liquid is n2, the refractive index of the transition matching liquid is ni, ni is greater than n2 but less than n1. The coupling efficiency can be improved, the technology complexity is reduced and the chip yield is improved based on not increase the original chip technology.

Description

technical field [0001] The invention relates to the field of optical communication devices, in particular to a coupling structure between an optical fiber and a high refractive index waveguide. Background technique [0002] Fiber coupling is an important issue in the packaging of optically integrated devices. The small waveguide cross-section makes high-index waveguide devices more compact. However, this also leads to a huge mode-field size mismatch between the fiber and the high-index waveguide, resulting in high coupling losses. [0003] Compared with tapered fiber, standard fiber has a larger spot size and is cheaper, which is the first choice in the industry. Using a vertical grating coupler is a commonly used coupling scheme from the fiber end face to the high refractive index photonic chip, which has a strong wavelength and polarization dependence. Using an inverted tapered coupler is another approach that avoids the wavelength and polarization dependence. The light...

AI Technical Summary

Problems solved by technology

[0004] At present, low-refractive-index waveguides are generally implemented with thickened film layers on the fiber end face, such as secondary low-refractive-index waveguides or polymer waveguides. These implementations require additional manufacturing processes when making chips, which may affect the performance of other waveguides. , which ultimately leads to a decrease in chip yield

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