Multi-Layer Phase Difference Detection for Parallel Laser Vibrometry
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Solution Overview
Problem
Existing laser Doppler vibrometry systems face limitations in integrating a large number of detectors on a single chip due to constraints such as bonding pads and waveguide routes, leading to bulkiness and complexity, especially in multi-beam systems, while scanning systems struggle with MHz frequency detection of transient events.
Innovation Solution
A phase difference detection system with a multi-layer structure using a planar waveguide and grating coupler to split laser beams into reference and measurement beams, which are inclined with respect to the normal direction, allowing for interference pattern detection without mixers or separate waveguides, enabling a large number of detectors on a single chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple separate LDV devices are implemented in the same system to measure multiple points simultaneously, then measurement capability at multiple positions is improved, but device complexity and bulkiness increase
Solution Approach 1:
The patent merges multiple LDV devices into a single integrated system by combining multiple phase difference detectors on one chip, sharing common components including laser source, waveguides, grating couplers, and imager array, thereby achieving multi-point measurement capability while reducing overall system complexity and bulkiness
Solution Approach 2:
The patent creates a universal platform where a single chip can perform multiple LDV measurements simultaneously at different target locations by configuring multiple phase difference detectors with shared optical paths and processing resources, enabling one system to serve multiple measurement functions
2Device complexity
If a scanning LDV system is used to measure multiple positions, then device complexity is reduced, but scanning frequency is limited and transient events cannot be detected
Solution Approach 1:
The patent segments the measurement function into multiple independent phase difference detectors operating in parallel on a single chip, each capable of simultaneous measurement at its designated target location, eliminating the need for sequential scanning while maintaining system simplicity through shared infrastructure
3Area of stationary object
If a large number of detectors are integrated on a single chip, then on-chip area is reduced, but constraints from bonding pads and waveguide routes increase device complexity
Solution Approach 1:
The patent transitions from planar two-dimensional layout to three-dimensional multi-layer architecture, routing waveguides and grating couplers across different vertical layers to interconnect multiple phase difference detectors, thereby reducing on-chip footprint while managing integration complexity through spatial organization
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 minimizes on-chip area requirements and allows for simultaneous detection of phase differences across multiple target locations, enhancing detection capabilities beyond MHz frequencies and reducing system complexity.
Implementation Method 1
a grating coupler to split the laser beam into a reference beam and a measurement beam
Implementation Method 2
an imager array configured to detect an interference pattern generated by a reference beam and an incoming beam
Implementation Method 3
an optical system configured to focus the measurement beam output from the phase difference detector on the single target location and to focus signals reflected at the target location to the phase difference detector
Implementation Method 4
a laser source to generate a laser beam
Implementation Method 5
a planar waveguide for guiding the laser beam
Data Source
AI summary
Example embodiments relate to phase difference detection systems and method for detecting phase difference. One embodiment includes a phase difference detection system for a single target location. The system includes a laser source to generate a laser beam. The system also includes a phase difference detector coupled to the laser source and having a multi-layer structure. The phase difference detector includes a planar waveguide for guiding the laser beam. The phase difference detector also includes a grating coupler to split the laser beam into a reference beam and a measurement beam. Additionally, the phase detector includes a planar imager array forming a second layer of the multi-layer structure. Further, the phase difference detector includes an optical system configured to focus the measurement beam output from the phase difference detector on the single target location and to focus signals reflected at the target location to the phase difference detector.