Waveguide Side Illumination at Steep Angles for Higher Coupling
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Solution Overview
Problem
Current methods for side illumination of waveguides, such as optical fibers, result in low light injection and transmission efficiency, leading to short propagation lengths, poor sensitivity, and low efficiency couplers.
Innovation Solution
Increasing the angle of side illumination to steep angles, up to 85 degrees relative to the waveguide normal, enhances light coupling by up to 100-fold, using configurations like collimated light sources, tapered holes, oblique and upright illumination waveguides, and hybrid configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If side illumination is performed at 0 degrees angle (normal to side surface), then the illumination setup is simple, but the light coupling efficiency is low resulting in short propagation lengths
Solution Approach 1:
The patent changes the illumination angle parameter from 0 degrees (normal to side surface) to steep angles (close to 90 degrees relative to normal, or parallel to waveguide axis). This parameter change increases the light coupling efficiency by up to 100-fold, enabling propagation lengths to extend from at most 2 meters to potentially much longer distances, while maintaining a relatively simple illumination setup without requiring complex optical components.
2Ease of operation
If side illumination is performed at 0 degrees angle, then the coupling setup is simple, but the signal strength is low resulting in poor sensitivity and resolution
Solution Approach 1:
By changing the illumination angle parameter to steep angles (parallel to waveguide axis), the patent increases the coupled light signal strength by up to 100-fold. This enhanced signal strength directly improves the sensitivity and resolution of optical fiber sensors, enabling more precise measurements while keeping the coupling setup simple and avoiding complex optical components.
3Ease of operation
If side illumination is performed at 0 degrees angle, then the illumination method is simple, but the coupling efficiency is low
Solution Approach 1:
The patent applies a parameter change to the illumination angle, transitioning from 0 degrees (normal to side surface) to steep angles (close to 90 degrees relative to normal). This change increases light coupling efficiency by up to 100-fold, dramatically reducing energy loss during the coupling process. The method remains simple as it does not require complex optical components like lenses or mirrors, achieving high efficiency through geometric configuration alone.
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 results in longer propagation lengths, higher sensitivity, and more efficient couplers, enabling the use of inexpensive light sources and reducing the need for complex detection systems.
Implementation Method 1
side illumination of waveguides... Increasing the angle of side illumination to steep angles, up to 85 degrees relative to the waveguide normal, enhances light coupling
Data Source
AI summary
Systems and methods of side coupling, side illumination or side injection (as opposed to axial coupling, illumination, or injection) of a waveguide are disclosed. More particularly, it relates to increased coupling, by orders of magnitude, and, consequently, increased transmission, along a waveguide, of any wave by side coupling, side illumination, or side injection.