Optical Multiplexer Reflection Groove Background Light Reduction
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Solution Overview
Problem
Conventional optical multiplexers face challenges in reducing background light and downsizing while maintaining image quality, as excess light from the discard port enters the cladding portion surrounding the output port, increasing background light intensity and degrading image sharpness.
Innovation Solution
The optical multiplexer incorporates a reflection groove that reflects excess light from the discard port, reducing background light. This is achieved by forming a cube-shaped or triangular reflection groove in the cladding layer, with a metal thin film on the bottom surface to enhance reflection efficiency. Additionally, the cladding layer is removed from the reflection groove to the output end surface, except around the output port, to further reduce background light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the discard port is curved and the distance to the output port is increased to reduce background light, then background light is reduced, but the device size is enlarged
Solution Approach 1:
The harmful excess light is extracted from the main light path by directing it into a separate discard port, preventing it from reaching the output port and affecting image quality
Solution Approach 2:
The discard port is configured to extend in a direction oblique to the light propagation direction, utilizing a different spatial dimension to separate excess light from the main optical path without increasing the overall device footprint
2Object-affected harmful factors
If the discard port is sufficiently separated from the output port to reduce background light, then background light is reduced, but the device size is enlarged
Solution Approach 1:
Instead of increasing the longitudinal distance between the discard port and output port, the invention utilizes an oblique direction extension to achieve spatial separation in a different dimension, maintaining compact device length while effectively isolating excess light
3Object-affected harmful factors
If conventional waveguide structures are used to suppress excess light, then background light reduction is attempted, but the device size cannot be reduced
Solution Approach 1:
The waveguide structure is segmented into a main light path and a separate discard port, allowing excess light to be diverted and eliminated without affecting the main optical path or requiring additional suppression structures
Solution Approach 2:
The discard port extends in an oblique direction relative to the light propagation, utilizing three-dimensional spatial arrangement to achieve compact integration while maintaining effective separation of excess light from the output
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 solution effectively reduces background light while allowing for downsizing of the optical multiplexer, thereby improving image quality by minimizing unsharpness caused by excess light.
Implementation Method 1
a reflection groove which reflects excess light outputted from a discard port of the directional coupler
Data Source
Figure 1(a)~2(b)
Figure 3(a)~4(b)
Figure 5(a)~5(b)
AI summary
An optical multiplexer reduced in background light and reduced in size is provided. The optical multiplexer takes a plurality of light beams having different wavelengths as input from respective waveguides, and outputs multiple light obtained by multiplexing the plurality of light beams by a directional coupler. Background light is reduced by a reflection groove which reflects excess light outputted from a discard port of the directional coupler, and downsizing of the optical multiplexer is achieved.