STP Resonator Waveguide for CMOS Mid-IR Fluid Sensors
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Solution Overview
Problem
Existing fluid sensors face challenges in achieving adequate sensitivity and cost-effectiveness, particularly in the integration of selective and efficient mid-infrared emitters/absorbers, which are often expensive and bulky, limiting their suitability for mass production.
Innovation Solution
A coupled waveguide-resonator system is introduced, comprising a multi-strip waveguide structure, a STP resonance structure, and an optical coupling structure, which enables selective emission and absorption in the mid-IR spectrum, allowing for narrowband mid-infrared radiation sources and fluid sensors that are compatible with low-cost CMOS manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If quantum cascade structures are used for selective emission and absorption in mid-IR, then measurement precision and emission efficiency are improved, but manufacturing cost and device complexity increase significantly
Solution Approach 1:
The patent replaces expensive quantum cascade structures with a cost-effective alternative using silicon-based waveguides and thermal emitters that can be manufactured through standard CMOS processes. The thermal emitter uses a simple heated element that generates broadband radiation, which is then spectrally filtered by the waveguide structure, eliminating the need for costly quantum cascade lasers while achieving comparable detection sensitivity.
Solution Approach 2:
The patent changes the operating parameters by using thermal radiation at elevated temperatures (e.g., 700-1000K) combined with spectral filtering through waveguide modes. This parameter change allows the system to achieve narrowband emission at specific mid-IR wavelengths without requiring the complex quantum cascade structure, thereby reducing manufacturing cost while maintaining measurement precision.
2Ease of manufacture
If doped nanowire thermal emitters are used for CMOS compatibility, then ease of manufacture is improved, but measurement precision deteriorates due to broad-band radiation spectrum
Solution Approach 1:
The patent introduces an intermediary spectral filtering mechanism using silicon-based waveguides that support specific guided modes at targeted mid-IR wavelengths. The thermal emitter produces broadband radiation, but the waveguide structure acts as a spectral filter, allowing only specific wavelengths to propagate. This intermediary filtering mechanism enables the system to achieve narrowband emission and high detection sensitivity while maintaining CMOS compatibility through the use of standard silicon materials and fabrication processes.
3Measurement precision
If conventional optical gas sensors are used, then detection capability is achieved, but device size and manufacturing cost increase
Solution Approach 1:
The patent transitions from conventional bulk optical components to planar integrated waveguide structures. By confining the optical path within a two-dimensional integrated circuit platform, the system achieves gas detection capability in a miniaturized form factor. The waveguide structure allows the light path to be folded and integrated within a small chip area, dramatically reducing the overall sensor volume while maintaining detection precision through the guided interaction of light with the gas sample.
Solution Approach 2:
The patent merges the light source, spectral filtering, and detection functions into a single integrated waveguide structure. The thermal emitter, waveguide resonator, and detector are combined on the same chip, eliminating the need for separate bulk optical components. This integration reduces device size while maintaining gas detection capability through the coordinated interaction of the merged components within the compact integrated platform.
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 enables high-efficiency emission and absorption, potentially rivaling the performance of quantum cascade structures, while being compatible with mass production methods, thus achieving the necessary sensitivity and cost-effectiveness for fluid sensors.
Implementation Method 1
An implementation possibility on this technical field are quantum cascade structures (both for emission and for absorption), which offer a good performance. However, integrated emitters and detectors, which may be implemented by means of quantum cascade structures (QCLs), require a heterogeneous integration of III-V elements by means of bonding (InGaAs potential wells).
Implementation Method 2
The semiconductor strips of the multi-strip waveguide structure and the semiconductor strips of the STP resonance structure are arranged perpendicular to each other in a common system plane.
Implementation Method 3
An alternative, inexpensive implementation possibility on this technical field has been so far a doped nanowire producing Joule heating and thermal radiation by making contact with a voltage source.
Data Source
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AI summary
An optical resonator system (100) comprises a multi-strip waveguide structure (120) having a plurality of spaced semiconductor strips (122-#) for guiding an IR radiation (RIR), a STP resonance structure (140) (STP = slab tamm-plasmon-polariton), wherein the STP resonance structure (140) comprises an alternating arrangement of semiconductor strips (142-#) and interjacent dielectric strips (144-#) and comprises a metal strip (146) adjacent to the semiconductor strip (142-2) at a boundary region (140-1) of the STP resonance structure (140), wherein the metal strip (146) and the adjacent semiconductor strip (142-2) are arranged to provide a metal-semiconductor interface (146-A) at the boundary region (140-1) of the STP resonance structure (140), and wherein the semiconductor strips (122-#) of the multi-strip waveguide structure (120) and the semiconductor strips (142-#) of the STP resonance structure (140) are arranged perpendicular to each other in a common system plane (180-A), and an optical coupling structure (160) having a semiconductor layer (162), wherein the semiconductor layer (162) is arranged between the multi-strip waveguide structure (120) and the STP resonance structure (140) for optically coupling the IR radiation (RIR) between the multi-strip waveguide structure (120) and the STP resonance structure (140).