Photonic Integrated Sensor Circuit for Waveguide Alignment
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Solution Overview
Problem
Existing methods for positioning optical probes relative to Photonic Integrated Circuits (PICs) lack precision, leading to inconsistent measurements and reduced repeatability and accuracy due to limitations in distance and angular alignment, with current techniques such as machine vision, optical power monitoring, and reflective laser sensors failing to provide sufficient nanometer-scale alignment feedback.
Innovation Solution
A Photonic Integrated Sensor Circuit (PISC) is used to measure the relative intensity and phase difference of probe light signals, enabling nanometer-scale detection of orientation and position adjustments through a sensor array and interferometric circuits, allowing precise alignment of optical probes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If machine vision systems are used for positioning, then ease of operation is improved, but measurement precision deteriorates due to diffraction-limited optical resolution
Solution Approach 1:
The patent replaces machine vision systems with interferometric sensors that use interference patterns of light to detect probe position and orientation. This substitution enables nanometer-scale measurement precision by utilizing the wave nature of light and interference phenomena, overcoming the diffraction limit that constrains machine vision systems.
Solution Approach 2:
The patent changes the measurement parameter from direct optical imaging to interference phase detection. By measuring the phase difference of interference patterns rather than direct images, the system achieves nanometer-scale precision in position and orientation measurements, dramatically improving measurement precision while maintaining ease of operation.
2Ease of operation
If optical power monitoring is used for positioning, then ease of operation is improved, but measurement precision deteriorates as optical signal saturates at 400-500 nm alignment precision
Solution Approach 1:
The patent replaces optical power monitoring with interferometric phase detection. Instead of measuring optical power which saturates at 400-500 nm precision, the system measures the phase difference of interference patterns, enabling nanometer-scale precision while maintaining the ease of automated operation.
Solution Approach 2:
The patent changes the measured parameter from optical power to interference phase. This parameter change allows the system to detect sub-nanometer displacements through phase variations, overcoming the saturation limit of optical power monitoring and achieving unprecedented measurement precision.
3Ease of operation
If external sensors are used for positioning, then ease of operation is improved, but measurement precision deteriorates due to lack of sensitivity for nanometer precision alignment
Solution Approach 1:
The patent replaces external magnetic or capacitive sensors with integrated interferometric sensors. The interferometric system uses light interference patterns to detect nanometer-scale changes in probe position and orientation, providing the necessary sensitivity that external sensors lack while maintaining automated operation.
Solution Approach 2:
The patent merges the sensing function directly into the photonic integrated circuit by integrating interferometric sensors on the same chip. This integration enables nanometer-scale measurement precision while maintaining ease of operation through automated feedback control.
4Measurement precision
If reflective laser sensors are used for positioning, then measurement precision is improved, but reliability deteriorates due to limitations in drift compensation and angular alignment
Solution Approach 1:
The patent merges the reference frame directly into the photonic integrated circuit by fabricating interferometric sensors on the same chip. This integration eliminates drift between separate components and provides stable angular alignment references, improving reliability while maintaining nanometer-scale measurement precision.
Solution Approach 2:
The patent creates an on-chip copy of the alignment reference structure that is thermally and mechanically coupled to the PIC. This copied reference structure moves with the PIC, automatically compensating for thermal drift and mechanical shifts, thereby improving reliability while maintaining precision.
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 PISC achieves unprecedented probe positioning resolution, improving measurement accuracy and repeatability by quantifying minute angular and positional variations, surpassing the limitations of existing techniques.
Implementation Method 1
a first optical interferometric circuit receiving said first and second sample signals of the probe light signal and generating a first set of interference signals
Data Source
AI summary
There is provided a photonic integrated apparatus for determining an orientation and/or a position of an optical waveguide, by measuring a relative intensity and a relative phase difference of the probe light signal incident on a sensor array. The phase profile of the probe light signal projected spatially on the sensor array is particularly sensitive to small changes in the optical probe's orientation and distance. The apparatus measures the relative intensity and relative phase difference of the probe light signal incident on a sensor array. A photonic integrated sensor circuit comprises the sensor array and one or more optical interferometric circuits. Changes in the sensed relative intensity and relative phase difference of the probe light signal, as sampled by the sensor array, indicate variations in the relative orientation and/or distance between the optical waveguide and the sensor array.