Acousto-Optic Waveguide Cladding Composition Tuning
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Solution Overview
Problem
Existing integrated acousto-optic structures that control the spectral position of the Brillouin gain curve suffer from higher optical losses and limited spectral range, as changing waveguide geometry affects both optical and acoustic modes, leading to complications in applications like optical gyroscopes.
Innovation Solution
A method of fabricating acousto-optic waveguides with adjustable waveguide claddings by varying the relative concentrations of cladding material components, such as nitrogen and oxygen, through precursor gas flow rates or doping, to tune the acoustic velocity and control the Brillouin gain spectral position, while maintaining low loss coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If waveguide geometry is changed to control the spectral position of the Brillouin gain curve, then the spectral position control is improved, but optical losses increase and the spectral tuning range is limited
Solution Approach 1:
The patent changes the material composition parameter of the cladding layer by adjusting the relative concentration of components (such as silicon dioxide and silicon nitride) to control the acoustic velocity and thereby tune the Brillouin gain spectral position, avoiding the need to change waveguide geometry which would increase optical losses
Solution Approach 2:
The patent uses composite cladding materials consisting of multiple components (e.g., silicon dioxide and silicon nitride) where the relative concentrations can be adjusted to achieve desired acoustic properties while maintaining low optical losses, resolving the contradiction between spectral control and loss minimization
2Measurement precision
If waveguide geometry is changed to control the spectral position of the Brillouin gain curve, then the spectral position control is improved, but the spectral tuning range is limited
Solution Approach 1:
By continuously adjusting the relative concentration of cladding material components during deposition, the patent achieves broad spectral tuning range (from 10 GHz to 30 GHz as shown in Figure 3) while maintaining precise control over the Brillouin gain spectral position, overcoming the limited tuning range of geometry-based approaches
3Measurement precision
If structures supporting guided acoustic modes are used, then Brillouin gain control is achieved, but optical losses increase
Solution Approach 1:
The patent changes the material composition of the cladding layer to control acoustic mode properties and Brillouin gain, rather than relying on geometric confinement that supports guided acoustic modes. This allows Brillouin gain control while maintaining low optical losses by keeping the optical mode well-confined in the core
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 approach allows for precise tuning of the Brillouin gain spectral position, enabling longer wave-mixing based on Brillouin scattering without optical power loss, and is applicable in integrated photonics applications like optical gyroscopes and Brillouin waveguide lasers.
Implementation Method 1
Brillouin gain spectral position control of waveguide claddings for tuning acousto-optic waveguides
Implementation Method 2
wave-mixing based on Brillouin scattering
Data Source
Figure 1
Figure 2A~2E
Figure 3
AI summary
A method of fabricating an acousto-optic waveguide that includes a waveguide cladding surrounding an optical core is disclosed. The method comprises providing a wafer substrate; depositing an initial amount of a first material over an upper surface of the wafer substrate to form a partial cladding layer; depositing a second material over the partial cladding layer to form an optical layer; removing portions of the second material of the optical layer to expose portions of the partial cladding layer and form an optical core comprising the remaining second material; and depositing an additional amount of the first material over the optical core and the exposed portions of the partial cladding layer to form a full cladding layer that surrounds the optical core. A relative concentration of components of the first material is adjusted to provide Brillouin gain spectral position control of the waveguide cladding to tune the acousto-optic waveguide.