Pune Vidyarthi Griha’s
College of Engineering and Technology & G. K. Pate
(Wani) Institute of Management
Approved by AICTE, DTE (Code:6274) |Affiliated to SPPU, Pune | NAAC Second Cycle ‘A’ Grade
Faculty Orientation Program
on BE(E & TC) Revised Syllabus 2019 Course
Subject: Fiber Optic Communication
Under the aegis of
Board of Studies E & TC SPPU, Pune
30th January to 1st Feb 2023
Organized by
Department of Electronics & Telecommunication
1
Pune Vidyarthi Griha’s
College of Engineering and Technology & G. K. Pate
(Wani) Institute of Management
Approved by AICTE, DTE (Code:6274) |Affiliated to SPPU, Pune | NAAC Second Cycle ‘A’ Grade
BoS_Faculty Orientation Program_FOC
on BE(E & TC) Revised Syllabus 2019 Course
Prof Tanuja Sachin Khatavkar
Resource Person_Unit 1
Faculty, E & TC Department
PVG’s COET & GKPIOM, Pune
email: tsk_entc@pvgcoet.ac.in
2
Unit I : Optical Fibers for Telecommunication (8 hrs)
Fundamentals of Optical Communication: EM spectrum - Optical Spectral bands, Shannon
channel capacity, power units (watts, dB & dBm), Block diagram of optical fiber communications
link, advantages of optical fibers.
Optical Fiber Waveguides: Introduction, Total internal reflection, acceptance angle, numerical
aperture, fiber types, mode theory for circular waveguides: overview of modes & key modal
concepts (V number, number of modes, power in clad), single mode fibers, cutoff wavelength
Transmission characteristics of optical fibers:
- Attenuation - material absorption, scattering losses, fiber bend loss, loss due to fiber
misalignment, splices and connectors;
Signal distortion – intermodal delay, intramodal dispersion or chromatic dispersion, modal delay,
bit rate-distance product, plot of material & waveguide dispersions for standard single mode,
dispersion shifted and dispersion flattened fibers; optical fibers for 5G networks, comparison.
MindMap
MindMap
EM spectrum - Optical Spectral bands
Designations of spectral bands used for OFC
Ref: T1:
Source: https://api.ctia.org/wpcontent/uploads/2018/06/what-is-spectrumgraphic.png
The spectrum of electromagnetic radiation
Spectral band designations used in optical fiber communications
Bitrate-distance Product
-
-
-
A commonly used
figure of merit for
communication
systems is the bit
rate–distance product,
BL, where B is the bit
rate and L is the
repeater spacing.
An increase of several
orders of magnitude
in the BL product
would be possible if
optical waves are
used as the carrier.
Increase in bit rate–distance product BL during the period 1850–2000.
The emergence of a new technology is marked by a solid circle.
Formulae:
Sample Numericals:
1. Calculate the carrier
frequency for optical
communication systems
operating at 0.88, 1.3,
and 1.55 µm. What is the
photon energy (in eV) in
each case?
2. What are the energies in
electron volts (eV) of
light at wavelengths 850,
1310, 1490,and 1550
nm?
https://www.informit.com/content/images/chap2_0201760320/elementLinks/02fig08.gif
Basic Construction of a Fiber Optic Cable
https://blog.biamp.com/
•400 nm to 770 nm Visible light
•770 nm to 1700 nm Infrared light
Shannon Channel Capacity
- In the analysis of any communication network, an important factor is channel
capacity (maximum rate at which data can be sent across a channel from
source to destination).
- Shannon-Hartley Theorem/Shannon Limit: reveals the limit to information
carrying capacity in bits per second. If a channel has a bandwidth B (Hz) then
the maximum information-carrying capacity C of that channel is given by:
C = BW log2(1 +SNR)
Shannon Channel Capacity
C = BW log2(1 +SNR)
- In practice this capacity cannot be reached.
- Considers only thermal noise & does not consider impulse noise, attenuation,
delay distortion.
- Raising the signal strength increases nonlinear effects in the system, which
leads to higher noise power.
- Increasing the bandwidth BW decreases the SNR, since wider the bandwidth
the more noise is introduced in the system.
Formulae:
Sample Numericals:
1. Calculate the maximum
capacity for a noisy
channel with a 1 MHz
bandwidth in which the
signal-to-noise ratio is 1.
2. Calculate the capacity of
a channel that operates
between 3 MHz and 4
MHz and in which the
signal-to-noise ratio is 20
dB
Power Units
Periodically placed amplifiers compensate for energy losses along a link
Example of pulse attenuation in a link. P1 and P2 are the power levels of a signal at points 1 and 2
Formulae:
Sample Numericals:
1. Convert the following
decibel power gains to
absolute power gains: –
30 dB, 0 dB, 13 dB, 30 dB,
10n dB.
2. Convert the following
absolute power levels to
dBm values: 1 pW, 1 nW,
1 mW, 10 mW, 50 mW.
3. Convert the following
dBm values to power
levels in units of mW: –
13 dBm, –6 dBm, 6 dBm,
17 dBm.
Block Diagram-OFC Link
Main constituents of an optical fi ber communications link
Main constituents of an optical fiber communications link
OEO-based Optical Link of ‘80s
Operating ranges of Components
Advantages of Optical Systems at a Glance
•Enormous capacity: 1.3 µm ... 1.55 µm allocates bandwidth of 37 THz!!
https://in.rsdelivers.com
/
•Low transmission loss: –Optical fiber loss can be as low as 0.2 dB/km. Compare to loss of
coaxial cables: 10 … 300 dB/km !
•Cables and equipment have small size and weight: –A large number of fibers fit easily into
an optical cable –Applications in special environments as in aircrafts, satellites, ships.
•Immunity to interference–Nuclear power plants, hospitals, EMP (Electromagnetic pulse)
resistive systems (installations for defense)
•Electrical isolation –electrical hazardous environments –negligible crosstalk
•Signal security–banking, computer networks, military systems
•Silica fibers have abundant raw material
Applications Areas of Optical Fibers
•Submarine
•Long haul
•Short haul
•Subscriber
• In-building
MindMap
Refractive Index (n) or Index of Refraction:
- A fundamental optical parameter of a material is the refractive index.
-
In free space a light wave travels at a speed c = 3 x 10^8 m/s.
- The speed of light is related to the frequency 𝝂 and the wavelength 𝛌 by c = 𝛌𝝂.
- Upon entering a dielectric or nonconducting medium the wave now travels at a speed
ʋ, which is characteristic of the material and is less than c.
- The ratio of the speed of light in a vacuum to that in matter is the index of refraction n
of the material and is given by n = c/ʋ
Reflection and Refraction:
Total Internal Reflection_ Meridional
ray representation
- Concept of Acceptance angle
- Numerical Aperture
- Concept of Critical angle
Skew rays
Formulae:
Sample Numericals:
1. Consider a multimode
silica fiber that has a core
refractive index n1 = 1.480
and a cladding index n2 =
1.460. Find (a) the critical
angle, (b) the numerical
aperture, and (c) the
acceptance angle.
2. Consider a multimode
fiber that has a core
refractive index of 1.480
and a core-cladding index
difference 2.0 percent (Δ=
0.020).
Find
the
(a)numerical aperture, (b)
the acceptance angle, and
( c) the critical angle.
sin〖θc=(n2/n1)〗
Low-order-mode fields
Formulae:
Sample Numericals:
1. Consider a multimode step-index
fiber with a 62.5-µm core
diameter and a core-cladding
index difference of 1.5 %. If the
core refractive index
is 1.480, estimate the normalized
frequency of the fiber and the
total
number
of
modes
supported in the fiber at a
wavelength of 850 nm.
1. Find the core radius necessary
for single-mode operation at
1320 nm of a step-index fiber
with n1= 1.480 and n2= 1.478.
What are the numerical aperture
and acceptance angle of
this fiber?
Formulae:
Sample Numericals:
1. Consider a multimode stepindex optical fiber that has
a core radius of 25 mm, a
core index of 1.48, and an
index difference Δ = 0.01.
Find the percentage of
optical
power
that
propagates in the cladding
at 840 nm.
2. A manufacturer wishes to
make a silica-core, stepindex fiber with V = 75 and
a numerical aperture NA =
0.30 to be used at 820 nm.
If n1 = 1.458, what should
the core size and cladding
index be?
Fiber Types & Comparison of fiber structures
MindMap
Formulae:
Sample Numericals:
1. Calculate the number of
modes at 820 nm and 1.3
µm in a graded-index fiber
having a parabolic-index
profile (𝛂 = 2), a 25-mm
core radius, n1 = 1.48, and
n2 = 1.46. How does this
compare to a step-index
fiber?
Formulae:
Sample Numericals:
1. Calculate the core radius
necessary for single-mode
operation at 1320 nm of a
step-index fiber with n1
= 1.480 and n2 = 1.478.
What are the numerical
aperture and acceptance
angle of this fiber?
1. A MMGI fiber has an
acceptance angle in air of
8°. Estimate the relative
refractive index difference
between the core axis and
the cladding when the
refractive index at the core
axis is 1.52
Transmission Characteristics - OFs
Formulae:
Sample Numericals:
1. Consider a 30-km
long optical fiber that has
an attenuation of 0.4 dB/km
at 1310 nm. Calculate the
optical output power Pout if
200 µW of optical power is
launched into the fiber.
Attenuation- Signal Degradation in OFs
Single Mode Fibers: The characteristics of SMF are wavelength dependent. Whereas the
attenuation of an optical signal is lowest in the C-Band and lower in L-Band, Chromatic
dispersion (CD) is least in O- band and zero at ~1310nm. Chromatic dispersion (CD) increases
as signal rate increases. Thus both attenuation and chromatic dispersion limits the reach of
the signal.
Single Mode Fibers: Access networks largely employ ITU-T G.652 single mode fibres (SMF).
The characteristic of single mode fibre with respect to attenuation and chromatic dispersion
is given in the figure over different optical bands.
Single mode fibre attenuation
and chromatic dispersion
Fiber Bending Loss
Power Loss in Curved Fiber
Microbending Loss
Bending effects on Loss
Mechanical misalignments
Longitudinal offset effect
Formulae:
Sample Numericals:
Two SI fibers exhibit the
following parameters:
a. A MM fiber with n1 = 1.5
and Δ = 3 % and an
operating wavelength of
820 nm.
b. An 8 µm core diameter SM
fiber with n1 same as in (a),
and a Δ = 0.3 % and an
operating wavelength of
1550 nm.
Estimate the
critical radius of curvature
at which large bending
losses occur in both
cases.
For indoor FTTx
applications which of the
above two would be
preferred & why?
Formulae:
Formulae:
Sample Numericals:
a. An OF has core
refractive index of 1.5.
Two lengths of fiber
with smooth and
perpendicular (to the
core axes) end faces
are butted together.
Assuming the fibers
are perfectly aligned,
calculate the optical
loss in dB at the joint
(due
to
Fresnel
reflection) when there
is small air gap
between the fiber end
faces.
MindMap
•Fiber dispersion results in optical pulse broadening and hence digital
signal degradation.
Fiber Dispersion – Bit Errors
•Pulse broadening limits transmission capability.
Chromatic Dispersion
•Chromatic dispersion (CD) may occur in all types of optical fiber. The optical pulse
broadening results from the finite spectral line width of the optical source and the
modulated carrier.
In the case of the semiconductor laser Δλ corresponds
to only a fraction of % of the centre wavelength λ0.
For LEDs, Δλ is likely to be a significant % of λ0.
Spectral Line Width
•Real sources emit over a range of wavelengths. This range is the source line width
or spectral width.
•The smaller the line width, the smaller is the spread in wavelengths or
frequencies, the more coherent is the source.
•An ideal perfectly coherent source emits light at a single wavelength. It has zero
line width and is perfectly monochromatic.
Light Sources
Line Width (nm)
Light-emitting diodes
20-100
Semiconductor laser diodes
1-5
Chromatic Dispersion
•Pulse broadening occurs because there may be propagation delay differences among the
spectral components of the transmitted signal.
•Different spectral components of a pulse travel at different group velocities
Chromatic dispersion
Example: GaAlAs LED is used at 𝛌0=1 µm. The source has a spectral width of 40 nm
and its material dispersion is Dmat(1µm)=40 ps/(nm x km). How much is its pulse
spreading in 25 km distance?
Modal Dispersion in Multimode Fibers
•When numerous waveguide modes are propagating,
they all travel with different velocities with respect to the
waveguide axis.
•An input waveform distorts during propagation because
its energy is distributed among several modes, each
traveling at a different speed.
•Parts of the wave arrive at the output before other
parts, spreading out the waveform. This is thus known as
multimode (modal) dispersion.
•Multimode dispersion does not depend on the source linewidth (even a single wavelength can be
simultaneously carried by multiple modes in a waveguide).
•Multimode dispersion would not occur if the waveguide allows only one mode to propagate - the
advantage of single-mode waveguides!
How does dispersion restrict the bit rate?
•As soon as pulses overlap due to broadening, the information can not be recovered properly.
•When this happens, depends on bandwidth and length of the transmission as well as on refractive index of
the core, cladding, and many more parameters.
•Bit rate - distance product: The Modal Bandwidth
–If a system is capable of transmitting 10 Mb/s over a distance of 1 km, it is said to have a BRD product of 10
MHz km.
–Note: the same system can transmit 100 Mb/s along 100m, or 1 Gb/s along 10m, … –Fiber specifications are
due to the BRD-product:
Transmission
Standards
100 Mb Ethernet
1 Gb
Ethernet
10 Gb
Ethernet
40 Gb Ethernet
100 Gb Ethernet
OM1 (62.5/125)
up to 2000 m
275 m
33 m
Not supported
Not supported
OM2 (50/125)
up to 2000 m
550 m
82 m
Not supported
Not supported
OM3 (50/125)
up to 2000 m
550 m
300 m
100 m
100 m
OM4 (50/125)
up to 2000 m
1000 m
550 m
150 m
150 m
Determining Link bit rate
•Link bit rate limited by
–linewidth (bandwidth) of the optical source
–rise time of the optical source and detector
–dispersion (linear/nonlinear) properties of the fiber
•All above cause pulse spreading that reduces link bandwidth
Chromatic dispersion
• Chromatic dispersion (or material dispersion) is produced when different
frequencies of light propagate in fiber with different velocities.
• Therefore chromatic dispersion is larger the wider source bandwidth is. Thus it
is largest for LEDs (Light Emitting Diode) and smallest for LASERs (Light
Amplification by Stimulated Emission of Radiation) diodes.
• LED BW is about 5% of 𝛌0 , Laser BW about 0.1 % or below of 𝛌0
• Optical fibers have dispersion minimum at 1.3 µm but their attenuation
minimum is at 1.55 µm. This gave motivation to develop dispersion shifted
fibers .
Chromatic and Waveguide dispersion
•In addition to chromatic dispersion, there exists also waveguide dispersion that is
significant for single mode fibers in longer wavelengths
•Chromatic and waveguide dispersion are denoted as intra- modal dispersion and
their effects cancel each other at a certain wavelength.
•This cancellation is used in dispersion shifted fibers.
•Total dispersion is determined as the geometric sum of intra-modal and inter-modal
(or mode) dispersion with the net pulse spreading:
Plot of Material & Waveguide Dispersions
SM Fiber Dispersions
Formulae:
Sample Numericals:
1. Consider a 1-km long
multimode step-index fiber
in which n1 = 1.480 and Δ =
0.01, so that n2 = 1.465.
What is the modal delay per
length in this fiber?
Formulae:
Sample Numericals:
1. A manufacturer’s data sheet
lists the material dispersion
Dmat of a GeO2-doped fiber
to be 110 ps/(nm.km) at a
wavelength of 860 nm. Find
the rms pulse broadening per
kilometer due to material
dispersion if the optical source
is a GaAlAs LED that has a
spectral width 𝞼𝛌 of 40 nm at
an output wavelength of 860
nm.
MindMap
Comparison
-
Based on the study, students should be able to compare different
types of fibers used for telecommunication.
https://community.fs.com/blog/itu-tstandards-for-various-opticalfibers.html
-
-
There
are
seven
common
ITU-T
Recommendations currently in effect at the
date of its publication:
ITU-T G.651.1, ITU-T G.652, ITU-T G.653, ITUT G.654, ITU-T G.655, ITU-T G.656, and ITU-T
G.657.
MindMap
Optical Fibers for 5G Networks
• 5G is the next global wireless network, the latest mobile network technology,
which connects billions of people and things. In addition to machines, objects,
and gadgets, 5G networks are intended to connect virtually everyone and
everything.
• 5G networks' enhanced bandwidth capacity, lower latency requirements and
complicated outdoor deployments bring challenges as well as unlimited
possibilities for optical fiber manufacturers, but our optical networks must
Optical Fibers for 5G Networks
Using 5G, we can enhance our lives by getting :
● faster downloads,
● lower latency, and
● more capacity and connectivity for billions of devices (especially in the fields of
virtual reality, the Internet of Things, and artificial intelligence)
• For example, you may access a variety of new and enhanced services, including
near-instant access to cloud services, multiplayer cloud gaming, augmented
reality shopping, real-time video translation and collaboration, and much more.
5 Types of Optical Fibers for 5G Networks
https://community.fs.com/blog/5-types-of-optical-fibers-for-5gnetworks.html
• It's known that 5G networks will offer consumers high-speed and low-latency
services with more reliable and stronger connections.
• But to make this happen, more 5G base stations have to be built due to the
higher 5G frequency band and limited network coverage.
• And it's estimated that by 2025, the total number of global 5G base stations will
reach 6.5 million, which puts forward higher requirements for the optical fiber
cable performance and production.
5 Types of Optical Fibers for 5G Networks
1. Bend Insensitive Optical Fiber for Easy 5G Indoor Micro Base Stations
2. OM5 Multimode Fiber Applied to 5G Core Networks
3. Micron Diameter Optical Fibers Enable Higher Fiber Density
4. ULL Fiber with Large Effective Area Can Extend 5G Link Length
5. Optical Fiber Cable for Faster 5G Network Installation
MindMap
Fiber Optic Communication-Course Details
CO-PO Mapping
Course
Outcome
Bloom’s
Taxonomy
Level
After successful completion of the course students will be able to
CO404190.1
2
Explain the working of components and measurement equipments
in optical fiber networks.
1,2,3,4,6
PO1
1,2,3,4
PO1, PO2
CO404190.2
3
Calculate the important parameters associated with optical
components used in fiber optic telecommunication systems.
CO404190.3
4
Compare and contrast the performance of major components in
optical links.
1,2,3,4
PO1
4
5
Evaluate the performance viability of optical links using the power
and rise time budget Analysis.
PO1, PO2,
PO5
1,2,3,4
6
Design digital optical link by proper selection of components and
check its viability using simulation tools.
1,2,3,4,5,6
6
Compile technical information related to state of art components,
standards, simulation tools and current technological trends by
accessing the online resources to update their domain knowledge.
PO1, PO2,
PO3, PO4,
PO5
PO1, PO2,
PO5, PO10
CO404190.4
CO404190.5
CO404190.6
Mapping
PO
with Syllabus
MAPPING
Unit
117
Revised Bloom’s Taxonomy Action Verbs
Teaching Methodology
Refer to the Teaching Methodology pdf.
Sample Numericals/Question Bank at different Cognitive Levels of Bloom’s
Taxonomy with mapping COs
Refer to the Sample Question Bank pdfs.
404195: Fiber Optic Lab
Experiments related to Unit 1
Group A
1. To estimate the numerical aperture of given MMSI optical fiber.
2. To measure attenuation coefficient and bending losses in optical fibers.
3. Tutorial on optical key components: numerical on optical fiber
Group C
2. Study of current trends in: fibers for telecommunication.
Simulation Software Recommended for Fiber Optic Lab
Optiwave Photonic Software
- Register on https://optiwave.com/register/
- Use domain email id for registration.
- Download OptiPerformer 19 version (latest version)- Evaluation software for 30
days.
- Click New and start to drag and drop components from the Components Library on
to the canvas.
- Set parameters for all components.
- Save, Run and simulate and verify the results.
404195: Fiber Optic Lab
Experiments related to Unit 1
Group C Faculty can plan ppt/write ups on state-of art components (brief) to be
compiled by group of students and submitted for TW.
2. Study of current trends in: fibers for telecommunication - Compile from Internet
[Sample] Type-wise Submarine OF cable length of Chennai-Andaman Sea
Link
Submarine Cables: Light weight (LW) Submarine OF Cable:
- These are types of cables that are used at 8000 meters’ depth of sea. It is suitable for
laying, recovery, and operation, where no special protection is required.
- At such depth the cables are to be protected mainly against strong sea bottom
currents, for this purpose the cables are provided with an extra layer of 2 to 3mm
diameter steel wires.
- These cables provide 1000 times abrasion resistance than Light Weight Protected
(LWP).
Optical fibre cables G.650–G.659 : This Recommendation describes a singlemode optical fibre and cable which has zero-dispersion wavelength around 1310
nm and which is optimized for use in the 1310 nm wavelength region
Fibers for LAN, MAN, and access networks
Application of G652D fibers:
● ITU-T G652D single-mode fibers are primarily used in networking and
communication.
● These G652D fibers have eliminated the water peak for the complete spectrum.
Hence, you can use both 1310 nm and 1550 nm. Therefore, you can use these
fibers for Coarse Wavelength Division Multiplexing (CWDM) transmissions.
Technical Specification of Fibre-ITU-T G.652.D
MOOC/NPTEL Courses
1. NPTEL Course on “Advanced Optical Communication”, by Prof R K Shevgaonkar, IIT Madras
Link of the Course: https://nptel.ac.in/courses/117101002
2. NPTEL Course on “Fiber Communication Technology”, by Prof Deepa Venkitesh, IIT Madras
Link of the Course: https://nptel.ac.in/courses/108106167
3. NPTEL Course on “Fiber- Optic Communication Systems & Techniques”, by Dr Pradeep Kumar K, IIT
Kanpur
Link of the Course: https://nptel.ac.in/courses/108104113
References
•Text Books:
1. Gerd Keiser, “Optical Fiber Communications” , 4th Edition, Tata McGraw Hill.
2. John M Senior, “Optical Fiber Communications”, 2nd Edition, PHI.
•Reference Books:
1. Djafar K Mynbaev and Lowell L Scheiner, “Fiber Optic Communications Technology”, 1stEdition, Pearson
Education.
2. Uyless Black, “Optical Networks- Third Generation Transport Systems,Pearson Education.
3. Govind P Agrawal, “Fiber Optic Communication Systems”, 3rd Edition, Wiley India.
● Internet Resources
Webliography
www.optiwave.com
https://optiwave.com/register/
https://finolex.com/optical-fibre-cables/
https://www.stl.tech/
https://www.corning.com/optical-communications/in/en/home/products/fiber-optic-cable.html
https://www.infinera.com
https://www.ciena.com/
https://www.itu.int/rec/dologin_pub.asp?lang=s&id=T-REC-G.652-200911-S!!PDFE&type=items#:~:text=652%20describes%20the%20geometrical%2C%20mechanical,in%20the%201550%20nm%20region.
https://www.flukenetworks.com/edocs/wp-demystifying-fiber-test-methods-backbasics#:~:text=The%20one%2Dcord%20method%20is,both%20ends%20of%20the%20cabling.
References
●
Prof. Hugo L. Fragnito, Fundamentals of Fiber-Optic Communication Systems, Optics and Photonics Research Center at Unicamp,
Brazil
●
Understanding ITU-T Standards for Various Optical Fibers: https://community.fs.com/blog/itu-t-standards-for-various-optical-
●
fibers.html
Optical Data Transmission in High Energy Physics - T. Flick
Disclaimer
The material for the presentation has been compiled from various sources
such as books, tutorials (online, offline), lecture notes, several resources
available on Internet. The information contained in this lecture/ presentation
is for general information and education purpose only. The information
shared through this presentation material should be used for educational
purpose only.
Suggestions are Welcome!
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