Dual Mach Zehnder Interferometer Force Sensor
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Solution Overview
Problem
Mach Zehnder-type interferometer (MZI) devices have a limited sensitivity range, making it difficult to differentiate intensity outputs when phase shifts exceed π radians, restricting their ability to accurately measure forces beyond a certain threshold.
Innovation Solution
The use of two MZI devices with different sensitivities, where one is highly sensitive for narrow ranges and the other is broad-range, allowing for complementary force measurement across a wider range by determining the applicable force range for the highly sensitive device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single MZI device is used for force sensing, then high sensitivity is achieved within a narrow phase shift range, but the sensitivity range is limited to phase shifts below π radians
Solution Approach 1:
The force sensing device is segmented into multiple MZI devices (first MZI device and second MZI device), each with different sensitivity characteristics. The first MZI device has a first sensitivity to applied force while the second MZI device has a second sensitivity that differs from the first, allowing each device to operate optimally within its own phase shift range. This segmentation resolves the contradiction by distributing the measurement function across multiple specialized sensors rather than relying on a single device to cover all ranges.
2Adaptability or versatility
If the phase shift exceeds π radians in an MZI device, then the measurement range is extended, but it becomes impossible to differentiate the intensity output from phase shifts below π radians
Solution Approach 1:
The second MZI device acts as an intermediary that provides coarse force range determination with lower sensitivity. Its intensity output serves as a mediator to identify which force range is applicable, enabling the selection of the appropriate first MZI device output for precise measurement. This intermediary device resolves the ambiguity of phase shifts exceeding π radians by providing contextual information about the overall force magnitude.
3Adaptability or versatility
If two MZI devices with different sensitivities are used, then the sensitivity range is greatly increased, but the device complexity increases
Solution Approach 1:
Both the first and second MZI devices are integrated into a single force sensing device that performs multiple functions: the first MZI device provides high-precision measurement within its optimal range, while the second MZI device provides coarse range determination and enables extended measurement capability. This multi-functionality justifies the increased complexity by delivering superior overall performance that neither device could achieve alone.
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 significantly increases the sensitivity range of the force sensing device, enabling accurate force determination both in narrow and broad ranges, while minimizing the impact of thermal and force gradients, and allowing integration into small-scale semiconductor devices.
Implementation Method 1
The light from the measurement and reference paths is then recombined and an optical intensity output from the MZI device is dependent on the phase difference of light between the two paths and, thus, on the pressure the measurement path is subject to
Implementation Method 2
a membrane, which is configured to deform upon receiving a force
Data Source
AI summary
A force sensing device comprises: a membrane (120), which is configured to deform upon receiving a force; a first Mach Zehnder-type interferometer device (110); a second Mach Zehnder-type interferometer device (130), wherein a first measurement propagation path (114) of the first Mach Zehnder-type interferometer device (110) and a second measurement propagation path (134) of the second Mach Zehnder-type interferometer device (130) are arranged on or in the membrane (120), and wherein the first measurement propagation path (114) and the second measurement propagation path (134) are differently sensitive to applied force on the membrane (120).