Multi-Junction Photodetector Layout for Continuous Spectral Coverage
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Solution Overview
Problem
Current photodetector systems using Silicon and Germanium-based photodiodes suffer from spectral responsivity gaps and discontinuities when measuring broad spectral ranges, requiring multiple detectors and resulting in complex systems.
Innovation Solution
A multi-junction detector device is designed with a combination of Silicon and Germanium photodiodes, where one detector reflects incident light to the other, minimizing spectral gaps by configuring the detectors in parallel circuit paths and using an integrating sphere to ensure continuous spectral measurement from ultraviolet to infrared wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple photodetectors from different materials are used to measure broad spectral ranges, then the spectral coverage is improved, but the system complexity increases
Solution Approach 1:
The patent combines multiple photodetectors (Silicon-based and Germanium-based) into a single integrated device housing with shared optical components and electronics. The detectors are positioned to receive light through a common entrance aperture and are coupled to a shared readout circuit, merging what would traditionally be separate measurement systems into one unified instrument.
Solution Approach 2:
The integrated device performs multiple spectral measurement functions simultaneously using different photodetector materials. The Silicon-based photodetector measures visible to near-infrared wavelengths while the Germanium-based photodetector measures infrared wavelengths, allowing the single device to universally measure across a broad spectral range from visible to infrared regions.
2Adaptability or versatility
If wavelength-dependent mirrors or filters are used to separate incident light, then the spectral separation is improved, but measurement precision deteriorates due to responsivity gaps
Solution Approach 1:
The patent uses a beam splitter as an intermediary optical element to divide the incident light path into two separate detection paths. The beam splitter directs different wavelength ranges to appropriate photodetectors based on their spectral sensitivity characteristics, enabling clean spectral separation without the sharp transitions and gaps associated with mirrors or filters.
Solution Approach 2:
The patent changes the spectral response parameters by selecting photodetector materials with complementary absorption characteristics. The Silicon-based photodetector is optimized for visible to near-infrared wavelengths while the Germanium-based photodetector is optimized for infrared wavelengths, creating overlapping spectral regions that eliminate gaps and ensure continuous coverage.
3Device complexity
If multiple layer sandwich detector is used, then the integration is improved, but measurement precision worsens due to wavelength dependent responsivity gaps
Solution Approach 1:
The patent applies local quality by positioning different photodetector materials in specific spatial locations within the device housing, optimized for their spectral sensitivity characteristics. The Silicon-based photodetector is positioned to primarily detect visible to near-infrared light while the Germanium-based photodetector is positioned for infrared detection, with their spatial arrangement and optical coupling designed to maximize their respective spectral ranges.
Solution Approach 2:
The patent implements dynamic spectral measurement capability by allowing the system to adaptively select which photodetector reads out data based on the wavelength range being measured. The device can dynamically switch between or combine readings from the Silicon-based and Germanium-based photodetectors depending on the incident light spectrum, providing flexible and precise measurement across varying spectral conditions.
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 multi-junction detector provides smooth, continuous spectral measurements across a broad range without spectral gaps, reducing system complexity and improving measurement accuracy.
Implementation Method 1
Silicon-based photodiodes and photodetectors typically produce significant photocurrents when irradiated with a signal having a wavelength from about 180 nm to about 1100 nm
Implementation Method 2
Germanium-based photodiodes produce significant photocurrents when irradiated with a signal having a wavelength from about 800nm to about 1800nm
Implementation Method 3
a beam splitter configured to reflect or transmit a portion of the incident signal
Implementation Method 4
a beam splitter configured to reflect or transmit a portion of the incident signal
Data Source
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AI summary
A novel multi-junction detector device and method of use is disclosed, which includes a housing, at least one mount system body positioned within the housing, at least one beam dump region formed in the mount system body, with a first detector having a first wavelength responsivity range positioned on the mount system body and at least a second detector having a second wavelength responsivity range positioned on the mount system body in optical communication with the first detector.