Optical Fiber Sensor

Fiber Bragg Grating Sensor
Optical Fiber Sensor
Pressure
FBG sensors that use optical fibers to enable the measurement
of a variety of parameters
Strain
Temperature
Acceleration
FBG* sensors that use optical fibers to enable the measurement
of a variety of parameters
*FBG : Fiber Bragg Grating
Outline
These sensors form a grating, which acts as the sensor unit, on optical fibers. Wavelength changes in
light reflected off the grating are picked up by these sensors as changes in physical parameters.
Measurement Principle
• Several sensor elements can be installed in one fiber. Each sensor
performs measurement independently.
• Moreover, several fibers can be connected in parallel in one system.
Incident light
Strain (1) Strain (2) Strain (3)
λ
FBG (1)
Reflected light
FBG (2)
FBG (3)
λ1
λ2
λ3
λ4
Humidity
Multi-axis
strain
Force
Temperature
λ5
λ6
λ7
λ8
Multi-axis
strain
Force
X-axis
strain
Y-axis
strain
Transmitted
light
The transmitted light is not used
for measurement
Circulator
λ3
λ2
λ1
Light reflected by FBG (1)
Light reflected by FBG (2)
Light reflected by FBG (3)
The amount of strain is measured by measuring the changes
of the reflected wave lengths λ1, λ2, and λ3.
Features
Intrinsic safety explosion-proof
performance
•
Since light is used instead of electricity, there is no need to supply electricity to the sensor
No fire hazard risk
Long-distance transmission
•
Transmission distance: From several km to several tens of km
Multi-point measurement
•
•
Several sensor elements can be installed in one optical fiber
Each sensor can perform measurement independently
• The sensors can be connected in parallel
•
Noise resistance and stability
•
•
Since light is used, the sensor is not affected by electromagnetic waves or lightning
Since the sensor is made of quartz glass, it provides excellent weather resistance
Fiber Bragg Grating Sensor
Application Examples
The FBG sensor can be used in a wide range of fields, and is currently attracting attention as a next-generation inspection and
diagnostic system.
Industrial
Instrumentation
Structural Health
Monitoring
Testing of Composite
Materials
Detection of Disasters
Temperature, pressure
and humidity measurement
Monitoring and diagnosis of
large-scale structures and
aircraft
Structural analysis and
non-destructive testing
Monitoring of earth pressure,
water levels, debris flows and
so forth
Industrial
Instrumentation
Evaluation Testing in High-Voltage Conditions
FBG sensors allow the measurement of strain and temperature in high-voltage conditions.
Example of strain analysis for pantograph
Example of temperature & strain measurement for train car members
*Cooperation provided by Railway Technical Research Institute.
複合材の検査
Testing of Composite Materials
Strain measurement of a high-pressure hydrogen tank
Testing of Composite
Materials
In contrast to conventional electric strain measurement, FBG sensor performs strain measurement of dangerous materials, such
as hydrogen gas, safely without any anti-explosion equipments.
Measurement of stress distribution*
The FBG sensor is affixed to a high-pressure hydrogen
tank and pressure distribution measurement and
non-destructive testing are performed.
*Analysis screens on PC.
Fiber Bragg Grating Sensor
Structural Health
Monitoring
Soundness Diagnosis for Bridge Pier (IMPACT Ⅳ*)
Detection of
Disasters
*IMPACT Ⅳ is a product distributed by the Railway Technical Research Institute.
For railroads, impact oscillation testing is used as a means of diagnosing the soundness of a bridge’
s substructure. IMPACT Ⅳ
is offered as a support system for such testing, and can be expanded upon for use in earth retaining with the use of a small
exciter.
Data Acquisition Software
Impact Oscillation Testing
Allows choice between
oscillation testing or sweep
testing
Signal
Small exciter
Choose from:
ImpactⅠ
Impact Ⅲ
Accelerometer (wired)
Accelerometer (optical fiber)
Small power amplifier containing
frequency sweep function
FBG acceleration sensor
Analysis Results
Reader
Schematic view of bridge pier
Scouring damage to bridge pier
By detecting changes in the natural oscillation of a bridge pier, this system can diagnose
soundness and detect scouring damage at an early stage.
*Cooperation provided by Railway Technical Research Institute.
*This product is distributed by the Railway Technical Research Institute.
Small exciter
Optical fiber accelerometer
Fiber Bragg Grating Sensor
Application Examples
Structural Health
Monitoring
Use in structural monitoring
The installation of a diagnostic sensor on a bridge for measurement purposes allows the soundness of that bridge to be
evaluated.
Various Measurement Sensors
FBG Accelerometer
FBG Clinometer
FBG Displacement Gauge
Bridge Installation Positioning Example
Cross-sectional View
Plan View
Accelerometer
Accelerometer
Displacement
Gauge
Clinometer
Displacement Gauge
Clinometer
Structural Health
Monitoring
Measurement of Progression in Changes
FBG sensors enable the monitoring of ground subsidence
during road construction.
Measurement data for angle of incline (5 mths)
Displacement gauge
Optical fiber clinometer
0.4
Incline No.1
Incline No.3
0.3
Incline No.2
Incline No.4
0.2
0.1
0.0
-0.1
-0.2
-0.3
-0.4
-0.5
Time Measured (1 graduation=48 hrs)
Measurement data for displacement (5 mths)
2
Displacement (mm)
Drain Construction Management (for Displacement/Inclines)
during Bypass Construction
Angle of Incline (deg)
0.5
1
変位No.1
0
変位No.2
-1
-2
-3
-4
-5
-6
-7
-8
Time Measured (1 graduation=48 hrs)
FBG Sensor Read Out Systems PF series
Features
High-speed sampling
The optical fiber grating sensor element of one axis or two axes can be sampled at high speed.
Expandability
With the PF series, sensor inputs can be connected to up to four channels. (Additionally, up to 30
sensor elements with a measurement range of 1,000με can be connected serially to one channel.)
Operability
With no external computer connected, PF series can be fully operated using the front control
panel with 8.4-inch display. The system can also be operated externally via LAN connection.
Functions
OSA (optical spectrum
analysis) mode
Spectrum analysis, which examines the intensity of light as a function of wavelength, can be
performed on the light reflected from each sensor element.
Data logging mode
The output of each sensor element is converted into physical parameters as strain and
temperature, and data can be recorded over a long period of time.
Specification
Item
Available sensor element type
Content
One-axis and two-axis sensors
Maximum number of sensor elements (per channel)
30 (In the case of the 1000µεmeasurement range)
Wavelength band
1530 to 1560 nm
Wavelength measurement precision
±10 pm
Wavelength measurement repeatability
±5 pm
Measurement power ranges
10 to -23 dBm
Laser output power
10 mW
Operating temperature range
0 to 50°C
Power source
100 VAC (50/60 Hz)
PF series
Measurement screen
The contents in the catalogue are subject to change without notice.
URL : http://www.naganokeiki.co.jp/
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13.5.A
（SA）

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