Waveguide End Structure Fabrication for Low-Loss Optical Coupling
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Solution Overview
Problem
Existing technologies face challenges in forming waveguide ends with small sizes due to process limitations, leading to increased coupling loss and reduced light propagation efficiency in silicon-based optical devices.
Innovation Solution
A fabrication method involving the formation of an initial waveguide groove in a dielectric layer, where a patterned layer is partially located within this groove, providing protection and stability, allowing for the stable formation of a small-sized waveguide end structure using the patterned layer as a mask to etch the dielectric layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a waveguide with gradual size reduction is adopted to form a small-sized tip, then the evanescent wave coupling effect is improved and coupling loss is reduced, but process limitations make it difficult to form waveguide ends with small size
Solution Approach 1:
An initial waveguide groove is formed in the dielectric layer before forming the patterned layer. This preliminary structure provides a pre-defined template that guides the subsequent formation of the small-sized waveguide end, enabling precise dimensional control that would be difficult to achieve through direct patterning alone.
Solution Approach 2:
The patterned layer is formed both on the surface of the dielectric layer and within the initial waveguide groove, creating a nested structure. This nested configuration allows the patterned layer to be precisely positioned and protected, enabling the formation of small-sized waveguide ends with high manufacturing precision.
2Ease of manufacture
If the patterned layer is formed on the surface of the dielectric layer, then it can be used as a mask to etch the dielectric layer, but the patterned layer may peel off due to process limitations
Solution Approach 1:
The patterned layer is nested within the initial waveguide groove structure, with portions of the patterned layer extending into the groove. This nested configuration provides mechanical anchoring that prevents peeling while maintaining the patterned layer's functionality as an etch mask.
Solution Approach 2:
The initial waveguide groove is formed as a preliminary structure before the patterned layer is deposited. This pre-formed groove provides a stable substrate and geometric constraint that enhances the adhesion and stability of the subsequent patterned layer, preventing peeling during processing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method reduces coupling loss and improves light propagation efficiency by ensuring the patterned layer's stability, enabling the formation of a small-sized waveguide end structure that minimizes peeling and enhances optical signal transmission.
Implementation Method 1
using the patterned layer as a mask to etch the dielectric layer, to form a waveguide structure on the substrate
Data Source
AI summary
An optical device and its fabrication method are provided. The method includes: providing a substrate including a coupling region; forming a first dielectric layer on the substrate; forming an initial waveguide groove in the first dielectric layer on the coupling region; forming a patterned layer on a surface of the first dielectric layer and in the initial waveguide groove, exposing at least a portion of a bottom of the initial waveguide groove; and using the patterned layer as a mask to etch the first dielectric layer, to form a waveguide structure on the substrate. The waveguide structure includes a waveguide end structure on the coupling region.