Tantalum Pentoxide Ridge Optical Waveguide
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Solution Overview
Problem
Existing optical waveguide devices face challenges in forming low-light propagation loss waveguides due to material hardness, processing difficulties, and poor adhesion of ridge portions, especially when trying to create curved or branched waveguides using mechanical processing or laser ablation.
Innovation Solution
A loaded-type optical waveguide device with a trapezoidal-shaped ridge portion made of tantalum pentoxide on a thin layer of lithium niobate or lithium tantalate, where the ridge portion is designed to have good adhesion and avoid peeling, allowing for flexible waveguide design and reduced propagation loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical processing or laser ablation is used to form waveguides in hard crystal materials, then waveguide formation is achieved, but propagation loss increases due to tipping and roughening
Solution Approach 1:
The patent replaces mechanical processing and laser ablation with a chemical etching process using buffered HF solution. This chemical method eliminates mechanical contact that causes tipping and avoids high-energy laser interactions that cause roughening, thereby achieving waveguide formation with significantly reduced propagation loss.
Solution Approach 2:
The patent changes the processing parameters by using a specific chemical etching solution (buffered HF with controlled concentration and temperature) and precise etching time control. This allows selective removal of material to form smooth waveguide structures without the defects associated with mechanical or laser methods.
2Adaptability or versatility
If stage movement in perpendicular direction is implemented for curved waveguide design, then design flexibility is improved, but cross-sectional deformation occurs increasing propagation loss
Solution Approach 1:
The patent applies a photosensitive resin pattern to the crystal surface before etching, which pre-defines the waveguide cross-sectional shape. This preliminary patterning ensures that during subsequent chemical etching and stage movements, the cross-sectional geometry is maintained accurately without deformation, enabling both design flexibility and manufacturing precision.
Solution Approach 2:
The photosensitive resin acts as an intermediary between the design intent and the final waveguide structure. It protects areas that should not be etched while allowing precise control of the etching front, thereby maintaining cross-sectional accuracy even when the stage moves in perpendicular directions to create curved waveguide routes.
3Ease of manufacture
If vapor deposition is used to form ridge portions, then loaded type waveguide is achieved, but adhesion is poor due to resist pattern evaporation introducing impurities
Solution Approach 1:
The patent extracts and removes the resist pattern after it has served its purpose as a mask during etching. By completely removing the resist before vapor deposition of the ridge portion, the source of impurities that would contaminate the interface and cause poor adhesion is eliminated, resulting in strong adhesion between the ridge portion and the crystal substrate.
Solution Approach 2:
The patent performs preliminary cleaning and surface preparation of the crystal substrate before vapor deposition of the ridge portion. This ensures that the surface is free of impurities from resist evaporation and other contaminants, creating an optimal surface for strong adhesion of the subsequently deposited ridge material.
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
The trapezoidal shape of the ridge portion improves adhesion and reduces propagation loss, enabling the creation of curved or branched waveguides with lower light loss, enhancing the productivity and reliability of optical waveguide devices.
Implementation Method 1
the ridge portion formed by lift-off process is composed of a vapor deposition film
Data Source
AI summary
An optical waveguide device 1 includes a thin layer 3 and a ridge portion 5 loaded on the thin layer 3. The thin layer 3 is made of an optical material selected from the group consisting of lithium niobate, lithium tantalate, lithium niobate-lithium tantalate, yttrium aluminum garnet, yttrium vanadate, gadolinium vanadate, potassium gadolinium tungstate; and potassium yttrium tungstate. The ridge portion 5 is made of tantalum pentoxide and has a trapezoid shape viewed in a cross section perpendicular to a direction of propagation of light. The ridge portion is not peeled off from the thin layer in a tape peeling test.