fiber optics applivations

1. FIBRE OPTICS
Mahabahu
3/28/2015
1

2. Represented by
Mohammed Ebada Ahmed L-kholy

3. Contents :
• Construction of optical fiber
• Principle of operation
• Total internal reflection
• Types of Optical Fibers
• Medical applications of optical fiber
• Military applications of optical fiber
• Fiber Optic Sensors

4. Construction of optical fiber
Core-thin glass center of fiber
where light travels.
Cladding-outer optical material
surrounding the core.
Buffer coating-plastic coating
that protects the fiber.

5. Principle of operation
Fiber-optic transmission of light depends on preventing light
from escaping from the fiber.
When a beam of light encounters a boundary between two
transparent substances, some of the light is normally
reflected, while the rest passes into the new substance.
A principle called total internal reflection allows optical fibers
to retain the light they carry.
When light passes from a dense substance into a less dense
substance, there is an angle, called the critical angle, beyond
which 100 percent of the light is reflected from the surface
between substances.

6. Total internal reflection
• At some angle, known as the critical angle θc, light traveling from a higher refractive
index medium to a lower refractive index medium will be refracted at 90° i.e. refracted
along the interface.
• If the light hits the interface at any angle larger than this critical angle, it will not pass
through to the second medium at all. Instead, all of it will be reflected back into the first
medium, a process known as total internal reflection
Incident angle =

7. Types of Optical Fibers
 Single Mode Fibre
 Multi mode optical fiber :
-Multimode StepIndexFibers
- Multimode GradedIndex Fibres

8. Single mode optical fiber
• This mode of optical fiber are used to transmit one
signal per fiber (used in telephone and cable TV).
• They have small cores(9 microns in diameter) and
transmit infra-red light from laser.

9. Multimode Step Index Fibers
• the index of refraction is a constant value
• The core is made from pure glass have a constant index of
refraction (n1)
• The cladding also have a constant index of refraction (n2)
n1>n2

10. Multimode Graded Index Fibres
 The index of refraction change gradually at the area of core .
 It gradually change from the center of core (n=n1 – Maximum value - )
to the seprative line between core and cladding (n=n2 – Minimum
value )
 This gradually change take different shapes (triangular , parabolic )

11. Types Of Optical Fiber
Single-mode step-index Fiber
Multimode step-index Fiber
Multimode graded-index Fiber
n1 core
n2 cladding
no air
n2 cladding
n1 core
Variable
n
no air
Light
ray
Index profile

12. They sense by detecting the modulation of one or more of the
properties of light that is guided inside the fiber—intensity,
wavelength, or polarization, for instance
Physical sensors measure a variety of physiological
parameters, like body temperature, blood pressure, and
muscledisplacement.
Medical applications of optical fiber :
Optical fiber sees growth as medical sensors :

13. Chemical sensors rely on fluorescence, spectroscopic, and
indicator techniques to identify and measure the presence of
particular chemical compounds and metabolic variables (such
as pH, blood oxygen, or glucose level). They detect specific
chemical species for diagnostic purposes, as well as monitor
the body's chemical reactions and activity.

14. Sensors intended for implanting or indwelling applications must be very small such
as this micro-miniature fiber-optic pressure sensor shown on a fingertip. (Courtesy of
Samba Sensors AB)

15. A fiber-optic intra-aortic force sensing catheter probe enables real-time
monitoring of the force exerted against the heart wall by the catheter.
(Courtesy of EndoSense )
The FBGs detect the force exerted against the heart wall by the stress
induced on them (see Fig. 3). Force control is essential for delivering
appropriate laser ablation pulses needed to produce lesions that are
induced in the heart walls to reduce abnormal electric activity

16. Military
OCC is the premier manufacturer of military ground tactical fiber optic cable
and connectivity solutions for the U.S. military

17. A fully qualified ground tactical fiber optic communications
cable for military applications :
• Announcing MIL-PRF-85045/8A certified fiber optic cables. Field
Proven... Now Certified. Optical Cable Corporation has always
manufactured the most rugged and robust fiber optic cables for the
military ground tactical market-field proven cables relied on by defense
agencies around the world
• This certification was granted after subjecting these fiber optic cable
products to an exhaustive series of optical, mechanical, and
environmental tests to ensure full compliance to the demanding
requirements of the United States military.

20. Coupled with deployable systems built for easy
implementation and retrieval, OCC’s military products
are designed for the needs of the soldier – rugged and
reliable – time and time again.

21. Why Use Fiber Optic Cable in a tactical
environment?
The 5 primary advantages of fiber optic cable over conventional coax
cable:
 Repeaterless Communications
 Fiber Optic – Repeaters every 16 kms (or more)
 Coax – Repeaters every 500 meters
 Weight
 Coax cable weighs approx. 5 times more than equivalent lengths of fiber
optic cable
 16 kilometers of coax cable weighs approx. 2,800 kgs, 16 kilometers of
fiber optic cable weigh approx. 550 kgs

22. • Higher Bandwidth
• Optimized for applications requiring voice, data, and video signals
• Security
• All dielectric. No signature
• Not affected by EMR
• Very difficult to tap. Reduces need for encryption
• Rugged
• More rugged than coax
• No memory

23. Fiber Optic Sensors
Fiber optic Bragg Grating sensor principle:
The basic principle of a fiber Bragg grating (FBG) based sensor system lies in the
monitoring of the wavelength shift of the returned Bragg- signal, as a function the measured
(e.g strain, temperature and force). The Bragg wavelength is related to the refractive index
of the material and the grating pitch. Sensor system involving such grating usually work by
injecting light from a spectrally broadband source into the fiber, with the result that the
grating reflects a narrow spectral component at the Bragg wavelength, or in transmission
this component is missing from the observed spectrum.

25. Civil structure applications:
• Bridges
• Dams
• Tunnels and Roads

26. Oil & Gas:
Pipelines are part of the backbone for modern community’s lifestyle and are absolutely
indispensable for transportation of water, gas, oil and all kinds of products.
Faults in these systems do not only result in service outages and financial losses but bear the
potential of spillages causing environmental pollution are even disasters accident.
Due to this, governments, engineering companies and industry associations have developed
design, operation and maintenances standards for pipelines based on which the number of leaks
could be reduced drastically since the 60’s and early 70’s of the last century.
As a result pipelines today are highly reliable and safe means of transportation.
For decades, electrical sensors have been used down hole to measure pressure, temperature, and
flow. Sensors are used to maximize production while minimizing risk to humans, the
environment and the production equipment. Fiber optic sensors are now in use where
traditional electrical sensors perform poorly or not at all. fiber optic sensors typically last longer
in these harsh environments, provide more reliable data, offer an attractive small size, and
perform in situations where actual sensor readings must be many tens of kilometers away from
the well head. Fiber Bragg Grating (FBG) optical sensors are particularly attractive as pressure
sensors and in long arrays with many temperature sensing points.
Other applications related to oil and gas where FBG sensors are ideal include monitoring
pipelines, off-shore platforms, storage facilities, tankers, and refineries. Passive fibers with long
range capability provide explosion proof monitoring of these critical assets.