It is a method used in glass optical fiber to imrove transmissions and reduce losses. Introdeuced in POF by doping and base material is significantly photosensitive at uv wavelengths. POF gratings can be fabricated by making use of these photo senstivities.
These are the four methods for introducing gratings in polymer optical fiber.
Polymer optical fibers
TOPICS TO BE DISCUSSED
Principle Of Optical Fiber Communication
History Of Polymer Optical Fiber
Comparison of Polymer and Glass Optical Fiber
Classification Of Pofs
Materials Used In Pofs
Application Of Pofs
Fabrication Of Pofs
Fabrication Of Si- Pofs
Fabrication Of GI- Pofs
Polymer Optical Fiber
Plastic Optical Fiber Passive Devices
Future Aspects Of Pofs
Potential Of Pofs
An optical fiber (or optical
fiber) is a flexible, transparent
fiber made by drawing glass or
plastic to a diameter slightly
thicker than that of a human
hair. Optical fibers are used
most often as a means to
transmit light between the two
ends of the fiber and find wide
usage in fiber-optic
communications, where they
permit transmission over longer
distances and at
Plastic optical fiber (POF)is
an optical fiber that is made out
of polymer. Similar to glass
optical fiber, POF transmits
light (for illumination or data)
through the core of the fiber.
PRINCIPLE OF OPTICAL FIBER
Principle of operation
- Total Internal
First introduced in 1960 by Dupont at nearly the same time
Glass optical fibers were introduced.
Faced problems of very high attenuation of the order of 1000
Application in communication almost impossible.
Mitsubishi Rayon, Japan improved Dupont’s technology to
reduce attenuation to 300dB/ km but still quite high value.
In 1980 Graded Index POFs were introduced.
New processing techniques such as swollen Gel
Polymerization helped reduced attenuation problem
In mid 1990s the use of POFs for short distance high speed
communication were introduced.
COMPARISON B/W POFs & GOFs
POLYMER OPTICAL FIBER
Plastic optical fiber, polymer
optical fiber is an optical fiber
which is made out of plastic.
It comprises of PMMA as the
core that facilitates the
transmission of light, and
fluorinated polymers as the
Simpler and less expensive
Greater flexibility and light
Bit rate upto 10Gbps.
GLASS OPTICAL FIBERS
Glass optical fiber, just as its
name shows, is an optical
fiber made of glass. Being a
delicate type of optical fiber,
it cannot be cut, spliced or
Difficult handling and
Less resistant to flexibility
and accidental breakage.
transmission capacity & lower
Used in low speed
and short distance
Generally in car
Used in longer
Under ground data
STEP INDEX POLYMER
A step index plastic optical fibre has a simple structure of a concentric
core and cladding. Consequently rather simple methods can be used for its
GRADED INDEX POLYMER
GI POFs has drawn considerable interest recently as a high band width
data transmission medium for short distance application .
MATERIALS USED IN POFs
PMMA are used as the core, with
refractive indices of 1.49.
Generally, fiber cladding is made
of silicone resin (refractive index
High refractive index difference is
maintained between core and cladding.
High numerical aperture.
Have high mechanical flexibility and
Industry-standard step-index fiber has a
core diameter of 1mm.
Attenuation loss is about 1 dB/m @ 650
Bandwidth is ~5 MHz-km @ 650 nm.
Fluorine (F) has a greater mass than
both H and D, allowing for lower
attenuation, theoretically approaching
that of silica glass fiber.
Fluorinated polymers such a s poly tetra
fluoro ethylene or Teflon) typically form
the crystalline structures.
Random copolymers result in the least
amount of crystallization.
Currently the application of POFs can be
divided into four major categories:
mechanical welds in
pipes and engines
(airlanes, rockets and
•Research is being conducted to
reduce attenuation and increase
bandwidth to increase usage in
long distance communication.
•Ideal for short distance
- New standard for LAN
-Material cost fall between
copper and glass.
-Ease of installation.
•Gigabit Ethernet- Transport of
1.25Gbit/s Ethernet traffic over
900 m has been demonstrated
Optical measurement of flow, biofilm growth, toxicity, rotation,
- POG with PVA film.
-Oil insulated power equipment.
- The fluoroscence produced by biological reaction is collected and
transmitted by POF.
•The number of electronic devices in
a car increases year by year,
primarily due to an increase in the
entertainment equipment desired for
modern passenger cars.
•This ubiquitous connection need is
a huge problem in networking
system designs for automotive
fiber from the viewpoint of both
physical space and system load.
Consequently, POF is specified in
the MOST standard to achieve the
lowest overall system weight and
FABRICATION OF STEP INDEX
A step Indexed plastic optical fiber has a simple
structure of a concentric core aand cladding.
Consequently rather simple fabrication techniques can
be applied for its fabrication, these techniques are
described as under.
1. Continous Extrusion Technique.
2. Preform Method
The polymer which becomes
the core of SI- POF is then
fed into a extruder by a gear
pump. The extruder is
capable of devolatalisation,
which removes monomer
residue and returns them to
the reactor. The core material
and the cladding material,
which are fed by separate
extruders, proceed into a
extrusion die where
concentric core - cladding
structure of an SI- POF is
PREFORM METHOD (SI POFs)
1. A cylindrical
preform 1-5 cm
in diameter and
upto 1 m in
length is made.
2. The preform is
drawn into a
fiber by heat
FABRICATION OF GI- POFs
GI- POF has drawn considerable attention in the recent past as a high
bandwidth data transmission medium. The bandwidth of the POF is
maximized by optimizing the Distribution of Refractive Index.
Thus in manufacturing of GI- POF, the obtainable bandwidth of a
GI POF is directly related to the ability to control profile. To date
several methods have been proposed to for the manufacture of GI
POF. These methods are described in the upcoming sections.
Swollen Gel Polymerization.
Closed Extrusion Method.
• A 2.9 mm diameter glass tube
was was filled with a monomer
mixture methyl methacrylate and
vinyl benzoate and an initiator
benzoyl per oxide. the glass tube
reactor was then positioned
vertically in a constant
temperature chamber and rotated
about its vertical axis
• It is irradiated by UV. the UV
radiation was applied locally by
using a shade while the UV lamp
transversed from the bottom of
the tubular reactor to the top at a
COPOLYMERIZATION (GI POFs)
A two stage process:
1. The monomer mixture is filled in the polymer tube to form gel at a lower
temperature to form a gel without significant copolymerization.
2. The temperature is raised to polymerization temperature to polymerize the
monomer, hence a rod is formed, which can be drawn into graded index
polymer optical fibre.
CLOSED CO EXTRUSION
METHOD (GI POFs)
• Versatile technology for making GI
•The figure shows a schematic
diagram of the a N layer internal
diffusion and surface evaporation co
•The tanks labeled 1- N are filled
with polymer melts.
•They are arranged so that when fed
to the concentric die the materials are
in decreasing order of the refractive
index of the polymers.
•It is thed passed through a hardening
zone H and is then receives by rolls.
The centrifugal method is regarded as a potential method for the
preparation of the GI polymer rods because of the ability to
form large diameter GI rods. The figure here shows the
schematic representation of the preparation of the GI polymeric
rods by centrifugal method. Many aspects of this method are still
POLYMER OPTICAL FIBER
Fiber Bragg Grating is
characterised by a periodic
index change induced by
ultraviolet irradiation in the
core along the fiber. Light
propagating along the fiber
grating is periodically and
partially reflected in
accordance with the pattern
of the index change. When
theses reflections are in
phase, they can produce an
enhanced near 100%
FABRICATION OF POF
ABLATION: This involves melting and burning the polymer
CHAIN SCISSION: This involves breaking the polymer chains,
thus decreasing the chain density, which in turns reduces the
CROSS LINKING: This involves inducing free radicals and then
giving rise to the combination of polymer chains. This has the effect
of increasing the density of chains, thus increasing the refractive
index of the polymer.
PHOTO POLYMERISATION: The incident light generates free
radicals , thus causing the polymerization of unreacted monomer
within the polymer. As a result, the polymerization density increases
and the refractive index increases accordingly.
POF PASSIVE DEVICES
In applications of POF such as
signalising, lighting, and decoration
systems, where it is necessary to
distribute or redirect incoming light
to other outgoing fibers, to split or
combine optical signals into two or
Large core optical fiber have as in
polymer optical fiber have a large
number of propogation node
which can cause to noise in
communication hence filters are
employed. Obtained by wrapping a
pof in a small diameter cylinder.
For some applications such as light
emitting diode to POF coupling,
step index to GI POF coupling,
collimation , it is necessary to
reduce the fiber diameter.
For many applications it is
necessary to use a Fiber
Integrated Lens, which is a device
that fits the fiber size and is used
to focus or collimate the the fiber
output light beam
solutions such as
•In comparison with glass optical fibers,
polymer optical fibers provide an easy and less
expensive processing of optical signals, and are
more flexible for plug interconnections .
• The use of polymer optical fibers as the
transmission media for aircrafts is presently
under research by different Research and
Development groups due to its benefits. The
German Aerospace Center have concluded that
“the use of Polymer Optical Fibers multimedia
fibers appears to be possible for future aircraft
•In the future, polymer optical fibers will likely
displace copper cables for the last mile
connection from the telecommunication
company’s last distribution box and the served
Hari Singh Nalwa.(Ed.).(2004). Polymer Optical
Fibers. American Scientific Publishers.
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• Wen-Chang Chen,
Jui-Hsiang Liu, Yung Chang, Ming-Hsin Wei, and Hong-Wen Su. Gradient-
Index Polymer Optical Fibers: Analysis of Fabrication Techniques. Taiwan.
• Giok-Djan Khoe, Henrie van den Boom,
and Idelfonso Tafur Monroy. High Capacity Transmission System. The
• G. D. Peng and P. L. Chu. Polymer Optical Fiber Gratings, Australia.
• Liliana R. Kawase. Plastic Optical Fiber Passive Device. Brazil.
An overview on fabrication method for polymer optical fibers.
Christian -Alexander Bunge. www.academia.edu
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