1. No category

Optical Fiber Sensing: Opt
ca be Se s g:
Sensing solutions from the macro world to the micro world
to the micro world Prof Gerald Farrell
Prof. Gerald Farrell, Director, DIT Photonics Research Centre
8th April 2015
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Overview
 Optical fiber sensing in general
 Application
A li ti areas
 Sensing solutions from macro to micro
 Futures directions and challenges
2
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Optical Sensing
 O
Optical
ti l Sensors
S
utilise
tili light
li ht tto measure/sense
/
a wide range of physical quantities
o Strain, temperature, distance, humidity
o Gas and liquid composition
Optical Image sensors
o Image sensing
o Selected bio- and chemical- quantities
q
 Optical fiber sensors use light but are based
on glass or plastic optical fiber
 Not just about light transport – the fiber itself
is the sensor
MEMS CO2 sensor
Bragg Grating Fiber
Sensor
3
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Advantages
g


Electrical strain gauge rosette
Wide variety of types, working on
many different principles
Singlemode
fiber
Advantages:
• Many advantages inherited from fiber itself;
• Low attenuation – long range;
• Immunity to electromagnetic interference;
• Not electrically conductive, usable with
Fiber optic equivalent
high voltage, in explosive or
chemically aggressive environments;
• Lightweight, small size;
• High sensitivity;
• Multiplexing possible – distributed sensing.
A380 fuel tank sensors
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
4
Wide variety of
Application Areas
Transport
Bridges and Civil
Structures
Oil-Gas Exploration
p
Medical
Bio-diagnostics
Energy Systems
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Security
Wide Range of Application
Scales
km
Macro scale, m-km
Medium scale, mm-m
To provide solutions for
a wide variety of
application areas,
sensors are needed for
measurements from a
nano/micro scale to a
macro scale
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Micro scale
scale, µm
Nano scale, nm
nm
What types of Fiber based
sensors are available?
Fiber bend loss based devices
Photonic Crystal Fibers
Fiber interferometric structures
Fiber Bragg and Long Period Gratings
Fiber Hetrostructures such as SMS
Liquid Crystal modified fibers
Tapered fibers
Periodically tapered fibers
Micro- and Nano-Fiber Resonators
Microfiber Couplers
Surface Plasmon Resonance Devices
Polarimetric fiber structures
Surface modified structures, for example using electrospun fibres
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
7
Variety of Fiber Sensing
Solutions to match Scale
Distributed sensors: Polarimetric, Brillouin
km
Macro scale, m-km
Grating based sensors, FBGs and LPGs
PCF based sensors, PCFIs
Medium scale, mm-m
Microfiber based
Mi
fib b d sensors, OMCs, Microresonators
Micro scale
scale, µm
Microfiber + Nanoparticles, LSPR
Nano scale, nm
nm
8
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
km
Macro scale Sensing
m-km
mm-m
µm
nm
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
nm
Structural Health Monitoring
– why do we need it?
R il B
Rail
Bridge
id collapse,
ll
D
Dublin
bli
2009
Composite Rudder failure
Ai b A310
Airbus
A310, 2005
Windmill blade failure,
Illinois, 2010
I35W Bridge collapse,
Minneapolis 2007
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
10
SHM Sensing for Composite
Materials



Composite materials are replacing many traditional materials in many sectors
Lightweight but very strong but still need SHM
Embedding sensors creates a smart material ”aware”
aware of its environment.
Boeing
g 787
Dreamliner
construction
Fibre Sensor embedded
in Aerospace Composite
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
11
Hybrid Sensing for
Composites

Simultaneous distributed measurement of strain,
strain temperature & vibration
and other parameters.

Research on utlising two sensor types working together: FBG sensors
combined with HB Polarimetric sensors



Aim is to overcome the limitations of the individual sensor technologies
Focus on aviation components under stress – struts, rotor blades etc.
Project with WUT: Smart Sensors for Engineering Structures (SSES)
Under carriage strut
MATERA - ERA-NET Materials
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
12
Strain and Temperature
Results
FBG and
d Polarimetric
P l i
i Sensors
S
-31.75
-32.1
FBG sensor
P l i t i sensor
Polarimetric
FBG sensor
Polarimetric sensor
-32.0
-31.70
Intensity dBm
m
Intensity dB
Bm
-31.9
-31.8
-31.7
-31.65
-31.60
-31.6
-31.55
-31.5
0
200
400
600
800
1000
1200
1400
1600
Applied Strain 
1800
-31
31.50
50
20
25
30
35
40
45
50
55
60
65
70

Temperature C
Change in intensity of the individual
sensors with applied strain
Change in intensity of the individual
sensors with
ith change
h
in
i temperature
t
t
A Photonic Crystal Fiber and Fiber Bragg Grating Based Hybrid Fiber Optic Sensor System”,
IEEE Sensors Journal, January 2012
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Sensing for Magnetoreological
Composites


Magnetoreological (MR) composites have controllable mechanical properties


Magnetic field can be used to control material stiffness and damping
Useful for adaptive elastomer structures, eg shock absorbers for earthquake
p
protection
Using optical sensing technology to provide strain feedback during curing and
also in use under magnetic control
Bridge Seismic
Elastomer
Bearing
Bridge Seismic
Shock absorbers
14
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Magnetoreological Cure
Sensing


Have demonstrated that PM-Sensors are superior to FBGs
MR Sample
PM-PCFs detect changes FBGs do not detect during curing
15
Ramakrishnan , Farrell et al - Monitoring curing of an MR – Electronics Letters 2013
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
km
Medium Scale Sensing
m-km
mm-m
µm
nm
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
nm
Optical Fiber Sensing for
Surgical Instruments
■ Modern surgical techniques,
techniques such a minimally invasive surgery (MIS) demand
“smart” surgical instruments
■ Sensors needed to provide accurate force feedback to the surgeon
■ Adds a sense of touch for the surgeon
Laproscopic or MIS Surgery
g y
Telerobotic
Surgery
Robotic Neurosurgery
Orthopaedic
O
th
di
Surgery
17
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Optical Fiber Sensing for
MIS Surgical Staplers
■ Surgical staplers and clip applicators allow a surgeon to join or close tissue
during MIS
■ Biggest
gg
issue is failure of the clip
p or staple
p which
causes complications for patient (8-9% of cases)
■ Challenges:
- Need for very compact sensors
- Temperature independence
- Integration and calibration
■ Sensors types:
- Minature FBGs
- PCF based sensors
Rajan, Farrell et al, IEEE Transactions on Biomedical Engineering, 2012
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Circular Stapler –
multiple staples
Clip Applicator
18
Photonic Crystal Fiber
Interferometer sensorized
MIS devices
• Miniature (~50 µm) PCFI strain
sensor using hollow core PCF.
Sensorised jaws of a surgical clip applicator
• High strain sensitivity
sensitivity, no
temperature compensation
required.
• Can be used to provide force
feedback for laparoscopic
devices during MIS procedures
procedures.
Ethicon laparoscopic clip applicator
50 µm
Jaws (0.5 cm)
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
PCFI Micrograph
19
Performance of a PCFI
sensorized
i d MIS device
d i
7
0
400
Strain sensitivity ~ 4.0 pm/
6
wavele
ength shift 
, nm
200
Strain, 
600 800 1000 1200 1400
5
4
3
2
o
Temp sensisitivty ~ 0.2 pm/ C
1
0
10
20
30
40
50
o
Temperature, C
60
70
Strain & Temp Sensitivity
“Photonic Crystal Fiber Strain Sensors for Laparoscopic Surgical Staplers”,
Mathews and Farrell etc al, Photonics Global Conference (PGC), Singapore, Dec 2012
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Breath Sensor using an
Infiltrated PCFI
•
Uses Agarose infiltrated photonic crystal fiber interferometer
•
Breath analysis application program for breath rate and pattern
•
High
g mechanical stability
y against
g
vibrations and air flow
•
Suitable for monitoring patients during an MRI scan
Highlighted in Nature Photonics in February 2013
A miniature optical breathing sensor, Biomed. Opt. Express, 2012
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
km
Micro scale Sensing
scale Sensing
m-km
mm-m
µm
nm
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
nm
Some Fiber Sensing Solutions
for the Micro World
Sensors include:
• Micro-Fiber Resonators
• Microfiber Couplers
• Surface Plasmon Resonance Devices
Periodically
Tapered Fiber
Micro Fiber Coupler
Transition region
Waist Transition region
Half taper
as a probe
Bismuth silicate
microsphere with full fiber
taper for I/O
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
23
Microfibers: a versatile
sensing platform
Standard optical
p
fiber with
a diameter of 125 µm
Microfiber with a
diameter of 3 µm
24
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Why Microfibre based
photonics for sensing?

Evanescent field confined to within 10 µm of fiber centre
centre, typical
macro glass fiber is 125 µm in diameter

Macro (traditional) fiber acts a “light
light pipe”:
pipe :
 Light guided in macro fiber sensors is immune to local environment
 Poor
P
solution
l ti for
f interaction
i t
ti with
ith llocall environment
i
t for
f many measurands.
d

What we need is a “light rail” – microfiber/nanowire
Conventional optical fibers: Light guided inside the fiber
Diameter = 125 μm
Optical microfibers: Light guided outside of the fiber
Typical diameters: 1-5 μm
25
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Microfiber Coupler
Output (P3)
Input
Transition
region
g
Waist
Transition
region
g
•
Taper a pair of fibres twisted together to form a
“Microfiber
Microfiber Coupler”
Coupler
•
Configuring a pair of microfibers as a coupler
means we can use wavelength domain
•
Wavelength domain proven to be stable, precise
and with the p
potential for multiplexing
p
g of many
y
sensors
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
O t t (P4)
Output
Dumbell cross section.
W kl ffused
Weakly
d fibers
fib
–
greatest sensitivity to local
environment
Microfiber Coupler Based Labelfree Biosensor (Fibrinogen –
Anti Fibrinogen)
Experimental
Broad Band
Source
Optical Spectrum
Analyzer
0
Diameter ~ 2.5 (×2) μm
Trans
smission (dB
B)
-5
-10
-15
-20
PBS phosphate buffered saline
Fibrinogen
Anti-Fibrinogen
-25
1550
1560
1570
1580
Wavelength (nm)
Analyte captured
Receptor immobilized
Bare microfiber
L. Bo, G. Farrell, et al, Optics Express, 2014.
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Probe type Microfiber
Refractive Index Sensor
•
Hybrid
H
b id structure
t t
incorporates
i
t a fib
fiber
hetrostructure and a Photonic Crystal Fiber
•
•
Relies of multimode interference to work,
•
Sensitivity 39.1 nm/RIU over an RI range of
1.33~1.38
V
Very
llow th
thermall sensitivity
iti it
Dip wavele
ength shifft (nm)
•
Tapered and then cleaved forming a probe
type sensor
1548.0
1547.5
Measured data
Linear fit
1547.0
1546.5
1546 0
1546.0
1.33 1.34 1.35 1.36 1.37 1.38
P. Wang, G. Brambilla, G. Farrell, et al, Optics Letters, 2014.
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Refractive index unit (RIU)
Nanoscale Sensing
km
m-km
Nanoparticle Enhanced Microfiber Sensors
Microfiber Sensors
mm-m
µm
nm
nm
500 nm
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Overcoming Microfiber
limitations
•
Decreasing the diameter of a microfiber increases the portion of light
energy in the evanescent field outside the fiber
•
•
Smaller microfibers with a diameter less than 1 µ
µm offer better sensitivity
y
Problem is that as fiber diameter decreases, fiber becomes more fragile and
difficult to manipulate and higher loss
Local Environment
Evanescent
Field
Distribution
Microfiber
Local Environment
30
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Metallic Au-Ag Nanoparticle
Enhanced Microfiber
• Evanescent
E
t field
fi ld excites
it
localised surface plasmon
resonance ((LSPR))
Evanescent field
Nanoparticle
• LSPR Resonance in the
UV/visible region
Microfibre
• Resonance is sensitive to
local environment
• Au-Ag alloy nanoparticles
combine best features of
Au and Ag
• Alloy mix allows for some
tunability
y
Evanescent field
++ + +
- Electron cloud
+
-
-
+ +
+
31
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Microfiber + Nanoparticle
probe

U-shaped
U
h
d microfiber
i fib (5 µm)) probe
b
samples formed,

Each coated with various nanoparticle
alloy mixes following surface
preparation
Higher Ag mixes show larger
absorbances – stronger LSPR
SEM Image
5 µm dia
di
A 25%Au75%Ag
Abso
orbance (AU
U)

16
1.6
1.2
0.8
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
C: 75%Au25%Ag
0.4
0.0
350
1.3 -1.4 mm
B 50%Au50%Ag
400
450
500
550
Wavelength (nm)
600
650
32
RI sensing using Microfiber
+ Nanoparticle probe
U-probe used to measure RI

Microfiber without
nanoparticles has negligible
response to RI



All three nanoparticle alloy
allo
mixes show an increase in
the LSPR peak absorbance
as RI increases.
Samples with higher Ag
content
t t exhibit
hibit hi
higher
h
sensitivities to RI
The highest sensitivity is
44.918 AU/RIU
2.5
LS
SPR absorbance (A
AU)

A' 25%Au75%Ag
20
2.0
1.5
B' 50%Au50%Ag
1.0
C' 75%Au25%Ag
0.5
1 33
1.33
1 34
1.34
1 35
1.35
1 36
1.36
Refractive index
33
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Conclusion
Future Directions and Challenges for Optical Fiber Sensing
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Fiber sensors can meet the
challenge of a wide variety
of application scales!
km
Macro scale, m-km
Medium scale, mm-m
Micro scale
scale, µm
Nano scale, nm
nm
35
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Some Future Directions for
Optical Fiber Sensing
 “Lab on a fiber” – multiparameter
sensing
g
 Sensors based on non-silica
fibers
 Wearable sensors for medical
applications
 Integration with microfluidics
 Ultra-high sensitivity sensors
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Pissadakis et al, microsphere
resonators
t
iin a MOF
253 µm
27 µm
16 µm
Rajan et al, Plastic Microfiber
with an FBG
Some Challenges for
Optical Fiber Sensing
 Lack of sensor standards
 N
Need
d more llong tterm reliability
li bilit
data
 Dealing with sensor
contamination
 Lower cost + compact +
common feature interrogation
systems
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Open ended PCFI Humidity
Sensor
FBG
interrogation
system
Thank you
Questions?
email: gerald
[email protected]
farrell@dit ie
Further details at: www.prc.dit.ie
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
Acknowledgements
This publication has emanated from activity
supported
d iin part b
by Science
S i
Foundation
F
d i
Ireland (SFI) under the International
Strategic Cooperation Award Grant Number
SFI/13/ISCA/2845.
Copyright © 2015, Prof. Gerald Farrell. Photonics Research Centre, Dublin Institute of Technology, Use for research or personal study is permitted
This work was supported by the 111 project
(B13015), att th
(B13015)
the H
Harbin
bi E
Engineering
i
i U
University
i
it and
d
also was supported by the National Natural Science
Foundation of China (NSFC) under grants
U1231201, 61275094