Photonic Integrated Circuit for Distributed Fiber Optic Sensor
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Solution Overview
Problem
Distributed fiber-optic sensors face challenges with bulkiness and significant light losses due to bulky interrogators and inefficient connections, which hinder accurate measurements and are prone to vibrations during operational tests.
Innovation Solution
A compact distributed fiber optic sensor system is developed using a heterodyne interrogator with a frequency shift module integrated into a photonic integrated circuit, reducing bulk and light losses, and enabling efficient temperature and deformation measurements through Raman, Brillouin, and Rayleigh effects analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bulky interrogators and waveguides are used to connect optical bricks, then the system can perform fiber optic sensing functions, but the system size increases and light losses increase
Solution Approach 1:
The patent merges multiple optical bricks (laser source, frequency shift module, optical amplifier, receiver) into a single integrated photonic circuit. This integration eliminates the need for separate bulky components and waveguide connections, significantly reducing the overall system volume while maintaining all necessary sensing functions.
Solution Approach 2:
The integrated photonic circuit performs multiple functions simultaneously - generating laser light, frequency shifting, amplifying, and receiving backscattered light - all within a single compact device. This multi-functionality eliminates the need for separate specialized components, reducing system size.
2Reliability
If bulky interrogators and waveguides are used to connect optical bricks, then the system can perform fiber optic sensing functions, but light losses increase at interconnections
Solution Approach 1:
By integrating all optical bricks into a single photonic circuit, the patent eliminates multiple interconnection points between separate components. This integration removes the sources of connection losses, allowing light to travel through a single continuous waveguide path with minimal attenuation rather than passing through multiple interfaces.
3Volume of stationary object
If integrated photonic circuit technology is used, then the size of the sensor is reduced, but the handling during operational tests generates light losses
Solution Approach 1:
The integrated photonic circuit is designed as a single robust unit that can be handled as one component during operational tests, rather than assembling multiple separate optical bricks. This integration reduces the number of connection points that could be disturbed during handling, minimizing light losses while maintaining compact size.
4Volume of stationary object
If a heterodyne interrogator with frequency shift module is integrated into a photonic integrated circuit, then the system becomes compact and vibration-resistant, but the complexity of the integrated circuit increases
Solution Approach 1:
The patent combines the laser source, frequency shift module, optical amplifier, and receiver into a single integrated photonic circuit. Although this integration increases the internal complexity of the circuit, it eliminates the need for multiple separate components and their interconnections, resulting in a compact, vibration-resistant system.
Solution Approach 2:
The patent replaces mechanical connections between separate optical bricks with an integrated photonic circuit design. This substitution of mechanical assembly with integrated photonic structures reduces the system's susceptibility to vibrations and mechanical disturbances while maintaining functional complexity.
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 system achieves significant reduction in size and light losses, enhancing measurement accuracy and resistance to vibrations, allowing for effective heterodyne or double-pulse detection of defects in optical fibers.
Implementation Method 1
Before injection into the fiber 4 to be tested, this light is frequency shifted by an offset Δf by a frequency shift and pulse generation module 6
Implementation Method 2
distributed temperature sensors using backscattering due to the Raman effect, shifting the spectrum of light by a few THz (Teraherz)
Implementation Method 3
distributed quasi-static strain and temperature sensors using backscattering due to the Brillouin effect. This effect creates a frequency shift, for a 1550nm (nanometer) wavelength laser, of about 11 GHz (Gigaherz)
Implementation Method 4
dynamic strain sensors (Dynamic Acoustic Sensors), which use backscattering due to the Rayleigh effect, which does not shift the light in frequency
Data Source
Figure 1~3
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Figure 6~7
AI summary
The present invention relates to a distributed optical fiber sensor system (1) comprising: - a frequency shift module (22) capable of frequency shifting the light received from a laser (16) and sending it into an optical circulation device (40) capable of transmitting the frequency-shifted light in an optical fiber (42), receiving a corresponding backscattered light, separating the backscattered light from the transmitted light, and sending the backscattered light to a receiver (46), - the receiver (46), capable of constructing from the backscattered light and non-backscattered light from the laser (16), an electrical signal representative of phase and/or amplitude differences between the backscattered light and the transmitted light, the system (1) comprising a photonic integrated circuit (30) in which the frequency shift module (22) is implemented.