Multi-Mode Waveguide Delay for Compact, Low-Loss Propagation
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Solution Overview
Problem
Conventional optical delay devices are large in size due to the use of long optical waveguides, necessitating a need for compact optical delay devices that can maintain efficient light propagation and reduce optical loss.
Innovation Solution
A multi-mode waveguide system with interconnected waveguides of varying widths and orientations, utilizing adiabatic and evanescent couplings to enable multipath light transmission and phase-matched mode conversion, allowing for compact optical delay devices with reduced optical loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If long optical waveguides are used in conventional optical delay devices, then the optical delay function is achieved, but the device size becomes large
Solution Approach 1:
The patent combines multiple waveguide modes (fundamental mode and higher-order modes) within a single multi-mode waveguide structure. By coupling light into different modes that propagate at different velocities, the device achieves extended optical delay without proportionally increasing the physical length, thereby reducing device size while maintaining the delay function.
Solution Approach 2:
The invention transitions from single-mode propagation to multi-mode propagation, adding the dimension of mode diversity. Different spatial modes within the same waveguide cross-section travel at different group velocities, enabling time delay differentiation without increasing the waveguide's physical footprint in the transverse plane.
2Loss of time
If long optical waveguides are used, then optical delay is achieved, but optical loss increases due to extended propagation distance
Solution Approach 1:
The patent combines multiple propagation paths (different modes) within a single waveguide structure. Since all modes travel through the same physical waveguide length rather than requiring separate long waveguides, the total propagation distance is effectively reduced, thereby minimizing cumulative optical loss while achieving the required time delay through velocity differences.
Solution Approach 2:
The invention uses mode coupling to create virtual copies of the light signal in different spatial modes. These mode copies experience different propagation velocities but share the same physical path, allowing the system to achieve extended delay without proportionally extending the physical waveguide length and associated losses.
3Area of stationary object
If compact optical delay devices are designed, then device size is reduced, but light propagation efficiency may deteriorate
Solution Approach 1:
The patent merges multiple mode propagation channels within a single compact waveguide structure. This consolidation maintains high propagation efficiency by utilizing the full cross-sectional area of the waveguide for multiple modes simultaneously, avoiding the need for multiple separate waveguides that would increase device size while potentially reducing overall efficiency.
Solution Approach 2:
The invention changes the propagation parameters by exciting different spatial modes within the same waveguide. Each mode has distinct propagation characteristics including different group velocities and confinement factors, allowing the system to achieve compact size while maintaining efficient light propagation through optimized mode selection and coupling.
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 system achieves compact optical delay devices with efficient light propagation and reduced loss by utilizing multipath transmission and mode conversion, enabling variable optical delay and minimizing interaction with waveguide sidewalls.
Implementation Method 1
a multi-mode waveguide for propagating first light through at least a first portion of the multi-mode waveguide. The first light propagates through at least the first portion of the multi-mode waveguide in a first mode
Implementation Method 2
a first coupler connected to the multi-mode waveguide and the first waveguide for coupling the first light from the multi-mode waveguide to the first waveguide
Data Source
AI summary
An optical device includes a first plurality of waveguides including a first waveguide and a second waveguide and a multimode waveguide delay comprising a first end and a second end. The first waveguide and the second waveguide are coupled to the first end of the multimode waveguide delay. The first waveguide is coupled to a first optical mode in the multimode waveguide delay. The second waveguide is coupled to a second optical mode in the multimode waveguide delay. The optical device includes a second plurality of waveguides including a third waveguide and a fourth waveguide. The third waveguide and the fourth waveguide are coupled to the second end of the multimode waveguide delay. The third waveguide is coupled to the first optical mode in the multimode waveguide delay. The fourth waveguide is coupled to the second optical mode in the multimode waveguide delay.