WDM Optical Coupler Bandwidth Extension for Confocal Fluorescence
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Solution Overview
Problem
In 2×2 WDM-type optical couplers, the transmittance of light changes sinusoidally with wavelength, leading to inefficient detection of fluorescence with broader spectra, as most fluorescence near the edges of the spectrum is branched to the wrong port, resulting in reduced efficiency and the need for multiple couplers for different fluorescent reagents.
Innovation Solution
A configuration using two WDM-type optical couplers with specific port connections and transmittance characteristics, where the first coupler directs excitation light to one port and fluorescence to another, and the second coupler directs longer-wavelength fluorescence back to the light detector, optimizing transmittance across a broader bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a single WDM-type optical coupler is used to match excitation light wavelength, then excitation light transmission is optimized, but fluorescence detection efficiency drops for wavelengths near the spectrum edges
Solution Approach 1:
The patent divides the fluorescence detection function across multiple WDM-type optical couplers with different transmittance characteristics. Each coupler handles specific wavelength ranges, with the first coupler optimized for excitation light transmission and the second coupler optimized for fluorescence detection across broader wavelengths including spectrum edges. This segmentation resolves the contradiction by allowing each coupler to specialize in its optimal wavelength range.
Solution Approach 2:
The patent creates a multi-functional optical coupling system where the combination of multiple couplers achieves both excitation light transmission and broad-spectrum fluorescence detection. The first coupler handles excitation light routing while the second coupler handles fluorescence collection, and together they provide universal functionality across the entire fluorescence spectrum including edge wavelengths that a single coupler cannot handle effectively.
2Measurement precision
If the optical coupler is optimized for a specific fluorescence peak wavelength, then detection efficiency at that wavelength is maximized, but efficiency drops remarkably when the fluorescence peak wavelength shifts
Solution Approach 1:
The patent designs an optical coupling system with multiple couplers that collectively provide universal adaptability to different fluorescent reagents. The first WDM-type optical coupler is configured to transmit excitation light across a broad wavelength range, while the second WDM-type optical coupler is configured to detect fluorescence across a broad spectral range. This multi-functional configuration maintains high detection efficiency regardless of the specific fluorescence peak wavelength, eliminating the need to change couplers when switching between different fluorescent reagents.
Solution Approach 2:
The patent utilizes parameter changes in the WDM-type optical couplers' transmittance characteristics to achieve adaptability. By selecting couplers with appropriate transmittance curves and combining them in series, the system can maintain optimal performance across varying fluorescence peak wavelengths. The parameter optimization of each coupler's spectral response allows the combined system to adapt to different fluorescent reagents without physical reconfiguration.
3Device complexity
If a single optical coupler is used for both excitation light transmission and fluorescence detection, then device complexity is reduced, but the bandwidth of detectable fluorescence is limited
Solution Approach 1:
The patent segments the optical coupling function into two specialized WDM-type optical couplers: the first coupler is optimized for excitation light transmission with its transmittance peak matched to the excitation wavelength, and the second coupler is optimized for fluorescence detection with its transmittance characteristics matched to the fluorescence spectrum. This segmentation enables broad bandwidth detection while maintaining relatively simple device architecture, as each coupler performs its specialized function efficiently without requiring a single complex multi-functional component.
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 configuration allows for efficient detection of fluorescence over a broader bandwidth, preventing efficiency drops due to wavelength mismatches and enabling handling of various fluorescent reagents without changing the optical coupler.
Implementation Method 1
a 2×2 WDM (wavelength division multiplexing) type optical coupler is provided with a first port and second port on the input side (output side) and a third port and fourth port on the output side (input side)
Implementation Method 2
The fourth port of the first WDM-type optical coupler and the fifth port of the second WDM-type optical coupler are optically coupled, and the second port of the first WDM-type optical coupler and the eighth port of the second WDM-type optical coupler are also optically coupled
Implementation Method 3
The fluorescence of the subject due to the emitted excitation light enters the third port and is guided through the second port to a light-receiving section
Data Source
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AI summary
A fourth port P4 of a first WDM-type optical coupler 18 and a fifth port P5 of a second WDM-type optical coupler 19 are optically connected, and a second port P2 of the first WDM-type optical coupler 18 and an eighth port P8 of the second WDM-type optical coupler 19 are optically connected. A light source 11 for emitting excitation light is connected to a first port P1 of the first WDM-type optical coupler 18, and a light-receiving section (light detector) 15 is connected to a sixth port P6 of the second WDM-type optical coupler 19. Excitation light is emitted through a seventh port P7 of the second WDM-type optical coupler 19 toward an observed subject, fluorescence from the observed subject is acquired through the seventh port P7 of the second WDM-type optical coupler 19, and input fluorescence is detected by the light-receiving section 15.