SmartScan FBG Interrogator
Features and Benefits
© Smart Fibres Ltd
SmartScan Description
• SmartScan is a dynamic interrogator for use
with fibre Bragg grating (FBG) sensors
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SmartScan Operation
It contains an electronically tuneable
laser which emits light at 400 discrete
wavelengths across a 40 nm
bandwidth on multiple fibres
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SmartScan Operation
Optical detectors inside SmartScan then
measure the light reflected from each
fibre at each of the 400 laser
wavelengths, so building up a spectrum
of the connected FBGs
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Zooming in on one FBG shows the laser tuning
points (seen as dots)
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SmartScan Operation
• The peak wavelength of
every connected FBG is
calculated by SmartScan’s
high-speed electronics at the
instrument sample rate of
2.5 kHz.
• This allows dynamic events
to be captured…
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A dynamic strain event sampled at 2.5 kHz
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SmartScan Unique Selling Points
Robustness:
• SmartScan’s light source is a widely
tuneable semiconductor laser with
the active optical elements contained in a tiny
monolithic chip, just a few millimetres long. All
other components are passive optical and
electronic components. This makes SmartScan very
robust and more tolerant of thermal and
mechanical influences than swept laser or
spectrometer based instruments.
• The instrumentation has demonstrated its
robustness in several military flight trials…
© Smart Fibres Ltd
SmartScan Unique Selling Points
Robustness:
• A SmartScan variant was
prepared for flight trials, and
passed the following pre-flight
ground tests:
Parameter
Operating Temperature
EMC: Conducted susceptibility
and conducted emissions
Acceleration
Vibration
Acoustic Noise
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Tested Capability
-15 to +55 °C
MIL-STD-416E
parts CS101 and CS 102
Vertical-Z (9g)
Lateral-X&Y (2.5g)
0.15 (g2/Hz) 0-100Hz
0.10 (g2/Hz) 100-1000Hz
MIL-STD-810F
SmartScan Unique Selling Points
Robustness:
• It then successfully completed a series of high and
low altitude flights on a BAe Systems Hawk, and
was assessed to have reached a technology
readiness level of 7 out of 9
© Smart Fibres Ltd
SmartScan Unique Selling Points
Robustness:
• The mean time before failure (MTBF) prediction
of the current, commercial grade SmartScan is
given below:
Environment considered
MTBF Prediction
Ground, Fixed, GF 40oC
4.2 years
Ground, Benign, GB 40oC
16.1 years
By parts count reliability method per MIL_HDBK_217F
• Future, enhanced environment variants are
expected to offer extended MTBF
© Smart Fibres Ltd
SmartScan Unique Selling Points
Speed:
• SmartScan’s agile laser and custom tuning circuits
allow data rates of 25 kHz for sequentially sampled
FBGs. This makes high speed vibration and other such
analyses possible with optical sensors.
© Smart Fibres Ltd
SmartScan Unique Selling Points
Resolution:
• SmartScan delivers sub-picometer resolution
per sample at 2.5 kHz. This allows oversampling and averaging to give extraordinary
resolution.
Example Data Set: SmartScan reading 2mm FBG, 1550 nm, 70%R, 0.7nm FWHM
STDEV Resolution
(pm)
STDEV Resolution
(microstrain)
60s, raw data - 2.5 kHz
0.39
0.33
60s, 10 averages – 250 Hz
0.13
0.11
60s, 100 averages – 25 Hz
0.06
0.05
60s, 1000 averages – 2.5 Hz
0.04
0.03
Data Averaging
Source data (6 MB) available to download
© Smart Fibres Ltd
SmartScan Unique Selling Points
Dynamic range:
• SmartScan’s laser has a high output power, giving a
39 dB dynamic range which allows it to interrogate
sensors tens of km away (for instance in a deep
subsea well).
• Sensor attenuation within this dynamic range is
compensated by 9x3dB gain stages which are
automatically set by the instrument.
• Uniquely, SmartScan offers automatic per-sensor
gain, such that if one or more sensors on a fibre
suffer attenuation, they are individually amplified
without affecting the other sensor gain settings
© Smart Fibres Ltd
SmartScan Summary
Below are the current SmartScan capabilities:
Parameter
Current Specification
Wavelength Range
40 nm
Number of fibres
1 to 4
Sensors per fibre
Up to 16
Scan frequency
Resolution
Wavelength Stability
Dynamic range
Enclosure
Comms Interface
© Smart Fibres Ltd
2.5 kHz all sensors simultaneously
up to 25 kHz each sensor in turn
Typ ⅓ microstrain per sample standard deviation,
reducing tenfold with averaging
5 pm over operating temperature range of -15 to +55 °C
Max 20 pm laser wavelength change over 25 years
39 dB (27 dB attenuation before performance loss)
9 automatic 3dB gain stages
Standard for field use, 140 x 110 x 70mm, 0.9 kg
Ethernet
SmartScan Development Roadmap
Below are future capabilities planned on the
SmartScan development roadmap:
Parameter
Wavelength Range
Number of fibres
Capability Target on Roadmap
Increase to 80 nm ü done
8, 16 ü done
Scan frequency
5 kHz all sensors simultaneously
up to 50 kHz each sensor in turn
Enclosure and
environmental
Re-packaging and qualification to suit requirements for:
• Fixed and rotary wing aerospace deployment ü done
• Global field deployments
• Deepwater subsea deployment
Comms Interface
© Smart Fibres Ltd
CANBus, ProfiBus etc ü done
End
Thank you for your attention
© Smart Fibres Ltd