Optical Multiplexer Tapered Waveguides RGB Coupler Bandwidth
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Solution Overview
Problem
Conventional RGB couplers have narrow transmission bands for green and blue light, leading to high propagation loss, which limits their ability to multiplex light effectively across a wide bandwidth.
Innovation Solution
An optical multiplexer using a multimode waveguide with tapered single mode input and output waveguides, where the multimode waveguide width is narrower than the input waveguides and connected via tapered waveguides, allowing for extended transmission bandwidth by balancing the effective width and wavelength, and further optimized using a wavefront matching method to modulate the refractive index distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional mode coupler is used for multiplexing green and blue light, then the device structure is simple, but the transmission band is narrow and propagation loss is high
Solution Approach 1:
The patent changes the geometric parameters of the waveguide, specifically using a multimode waveguide with a smaller width (3.0 μm) compared to the input waveguides (4.0 μm). This parameter change extends the transmission bandwidth for green and blue light while maintaining low propagation loss (1 dB or less). The tapered connection between waveguides of different widths further optimizes the mode matching and reduces loss.
2Area of stationary object
If the multimode waveguide width is reduced to extend transmission bandwidth, then the transmission band widens, but the coupling efficiency may deteriorate
Solution Approach 1:
The patent employs tapered waveguides that provide a gradual transition in width between the input waveguides (4.0 μm) and the multimode waveguide (3.0 μm). This dynamic transition structure maintains mode matching and coupling efficiency while enabling the multimode waveguide to support extended bandwidth for green and blue light multiplexing.
3Adaptability or versatility
If conventional waveguides are used for green and blue light multiplexing, then the device is easy to manufacture, but the transmission bandwidth is insufficient for wide color gamut
Solution Approach 1:
The patent applies different waveguide structures to different functional regions: single-mode input waveguides for light input and a multimode waveguide with smaller width for bandwidth extension. The tapered transition regions provide local adaptation between these structures. This localized optimization achieves extended transmission bandwidth for wide color gamut while maintaining manufacturability through standard PLC fabrication processes.
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 design achieves a broader transmission band with reduced propagation loss, ensuring efficient multiplexing of green and blue light within 1 dB across a wider range of wavelengths, improving overall transmittance and matching the desired color gamut standards.
Implementation Method 1
the input waveguides are connected to the multimode waveguide and the multimode waveguide is connected to the output waveguides via tapered waveguides
Implementation Method 2
a width of the multimode waveguide is smaller than widths of the two input waveguides plus a distance between the input waveguides
Implementation Method 3
an optical multiplexer that extends transmission bandwidths of light
Data Source
AI summary
An optical multiplexer that extends a transmission bandwidth of light is achieved. The present invention provides an optical multiplexer constructed of a multimode waveguide to which two single mode input waveguides are connected at a distance and two single mode output waveguides connected at a distance to a surface opposite a surface to which the input waveguides of the multimode waveguide are connected, in which a width of the multimode waveguide is smaller than widths of the two input waveguides plus a distance between the input waveguides, and the input waveguides are connected to the multimode waveguide and the multimode waveguide is connected to the output waveguides via tapered waveguides, respectively.