Fiber Optics Communications System (1)

7/27/2019 Fiber Optics Communications System (1)

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DIELECTRIC WAVEGUIDE &

FIBER OPTICS TRANSMISSION

MEDIA

COMEC 513 L1

SABILE, s.s.


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DIELECTRIC WAVEGUIDE & OPTICAL FIBER

Index of Refraction

Snells Law

Critical angle

Reflection Coefficient


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Dielectric Waveguide

Let us consider the simpler case of a rectangular

slab of waveguide.

r

i r

1 1 1 2 2 2and

Snells Law of Reflection

1

2

sin

sin

t

i

Snells Law of Refraction

21

1

sinr

i critical

r

Critical Angle:

Case(1): i criticali Case(ii): i criticali

When the incident angle is greater than the critical angle, the wave is totally

reflected back and this phenomenon is known as Total internal reflection.

Total internal

reflectionIncident

waveReflected

wave

Refracted

wave

Incident

wave


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Velocity of light in Free Space

Velocity of light in the mediumu

r r

cn

u


The index of refraction, n, is the ratio of the speed of light in a vacuum to the

speed of light in the unbounded medium, or

In nonmagnetic material

rn

1 2

1

sini critical

n

n

1

2

sin

sin

t

i

n

n

1 1 1 1u

o r o r o o r r r r

cu

1

o o

c

1r

Where

Critical Angle:

Snells Law of Refraction:

Snells Law of Refraction can be expressed in terms of refractive index:

Index of refraction:


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A slab of dielectric with index of refraction 3.00 sits in air. What is the relative

permittivity of the dielectric? At what angle from a normal to the boundary willlight be totally reflected within the dielectric? (Ans: 9, 19.5)

Dielectric WaveguideExample

What is the relative permittivity of the dielectric?

1 3n 2 1 (air)n

Criticali

11 rn

2

1 1r n

2

13 9r

At what angle from a normal to the boundary will

light be totally reflected within the dielectric?

1 12

1

1sin sin

319.5

i critical

n

n


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Dielectric WaveguideTE wave

1 2

1 2

cos cos

cos cos

i t

i t

n n

n n

22

2 11sin

2tan

cos

i

TE

i

n n

Ex

Hy

Hz

222 1

22

2 1

cos sin

cos sin

i i

TE

i i

j n n

j n n

TE

Using Snells Law of refraction

The reflection coefficient of a TE plane wave

(See Chapter 5) is given by

22

2 1

1

sincostan

2 2 cos

i

i

i

n na m

TE modes (50 mm thick dielectric ofr= 4 or

n=2 operating at 4.5 GHz)

TE wave

LHS RHS

RHS

LHS

For this example only three TE

modes are possible;

A) TE0 at i = 74.4,

B) TE1 at i = 57.9, and

C) TE2 at i = 39.8.

(A)(B) (C)

Possible modes can be obtained by evaluating

the phase expression for various values of m.


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Dielectric WaveguideTM wave

Ex

Hy

Ez

22

2 1

22

2 1

cos sin

cos sin

i i

TE

i i

j n n

j n n

TE

Using Snells Law of refraction

The reflection coefficient of a TM plane wave

(See Chapter 5) is given by

TM modes (50 mm thick dielectric ofr

= 4 or n=2 operating at 4.5 GHz)

TM wave

1 2

1 2

cos cos

cos cos

t i

TM

t i

n n

n n

22

2 11

2

2 1

sincostan

2 2 cos

ii

i

n na m

n n

For this example only three TM

modes are possible;

A) TM0 at i = 71.6,

B) TM1 at i = 52, and

C) TM2 at i = 33.

RHS

LHS

(A)

(B)(C)

LHS RHS

Possible modes can be obtained by evaluating

the phase expression for various values of m.


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A larger ratio of n1/n2 results in

a) a lower critical angle and therefore

b) more propagating modes.

22

2 11

2

2 1

sincos

tan 2 2 cos

ii

i

n na m

n n

LHSRHS for various mRHS

For single mode operation:

2 2

1 2

1 1

2o

a

n n

2 2

1 2

1

2

o

n n

a

(or)

:Slab thicknessa

2 2

1 2

1

2

c

n nf

a

oc

f

Using


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D7.6: Suppose a polyethylene dielectric slab of thickness 100 mm exists in

air. What is the maximum frequency at which this slab will support only onemode?

100 mma

2 21 2

1

2

c

n n

f

a

1 1.5n

2 1 (air)n

From Table E.2, for polyethylene

1 2.26 1.5n 1 2.26r

2 1 (air)n

The maximum frequency at which this

slab will support only one mode is

2 2

1 2

8

max2 23

1 1

2 2

3 101.2 GHz

100 10 1.5 1.0

c

n nf

a

Example


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D7.6: Find e and up at 4.5 GHz for the TE0 mode in a 50 mm thick n1 = 2.0

dielectric in air. (Ans: 35 mm and 1.6 x 10

8

m/s)

Example

1 1

8

9sin sin sin sin

3 1035 mm

4.5 10 2 74.4

u o

e

i i i

c

n fn

The effective wavelength in the guide is

1

8

8

sin sin

3 101.6 10 m/s

2 74.4p

e i

cu

n

The propagation velocity is

50 mma

1 2.0n

2 1 (air)n

2 1 (air)n From Fig. 7.16, the critical incident angle for

the TE0 mode

TE0 at i = 74.4



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FIBER OPTICS

COMMUNICATIONS SYSTEM


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FIBRE OPTIC COMMUNICATION SYSTEM

Introduction

Fibre optic system is a communication system that

carries information through a guided fibre optic

cable

Light frequencies used in fibre optic systems are

between 1014 and 4x1014 Hz

Thus, the higher the carrier frequency, the wider

the bandwidth and consequently, the greater the

information carrying capacity

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OPTICAL FIBER

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OPTICAL FIBER - BENEFITS

Greater capacity

Data rates of hundreds of Gbps

Smaller size & weight

Lower attenuation

Electromagnetic isolation

Greater repeater spacing

10s of km at least

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OPTICAL FIBER - TRANSMISSION CHARACTERISTICS

Act as wave guide for 1014 to 1015 Hz

Portions of infrared and visible spectrum

Light Emitting Diode (LED)

Cheaper

Wider operating temp range

Last longer

Injection Laser Diode (ILD)

More efficient

Greater data rate

Wavelength Division Multiplexing15


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THE LIGHT SOURCE


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Fibre optics Long thin strand of glass or plastic fibre used to guide light rays from

a point to another point

Fibre-to-detector coupler Interface between fibre and light detector to couple as much light as

possible from the fibre cable into the light detector

Light detector PIN (p-type-intrinsic-n-type) diode / an APD (avalanche photodiode)

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Fibre optic - Basic elements


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FIBER OPTIC TYPES

multimode step-index fiber

the reflective walls of the fiber move the light pulses to the

receiver

multimode graded-index fiber acts to refract the light toward the center of the fiber by

variations in the density

single mode fiber

the light is guided down the center of an extremely narrowcore

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OPTICAL FIBER TRANSMISSION MODES

19


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FIBER OPTIC SIGNALS

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fiber optic multimode

step-index

fiber optic multimode

graded-index

fiber optic single mode


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PROPAGATION MODE Monomode fiber (core 8 ~

12 m)

Only one path for the light

to propagatealong fiber

All light rays follow the

same path down

the cable and take the

same time to

travel the length of the

cable

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input pulse output pulse

only one mode, no modal dispersion

Monomode step-index fiber


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PROPAGATION MODE

Multimode step index fiber

(50 ~200 m)

More than one path for lightpropagate along fiber

Light rays are propagated down

the cable in a zig-zag pattern

and all the light rays do notfollow the same path with

different propagation time

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fastest modeslowest mode


Multimode step-index fiber


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PROPAGATION MODE

Multimode graded indexfiber

Light is propagated downthe fiber by refractionwhich result a continuousbending at the light rays

the rays travel near thecenter, so that all the raysarrive at the end point atthe same time

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Multimode graded-index


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FIBEROPTIC - ADVANTAGES

Wider bandwidth: have higher information to carry Lower loss/attenuation: there is less signal attenuation

over long distance

Light weight: higher than copper cable and offer good

benefit where weight is critical (plane) Small size: smaller diameter than electrical cable

Strength: as it has cladding, they offer more strength

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FIBER OPTIC ADVANTAGES

greater capacity (bandwidth of up to 2 Gbps)

smaller size and lighter weight

lower attenuation

immunity to environmental interference

highly secure due to tap difficulty and lack of signalradiation (Security: cannot be tapped easily aselectrical cable)

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FIBER OPTIC DISADVANTAGES

expensive over short distance

requires highly skilled installers

adding additional nodes is difficult

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ATTENUATION

The attenuation in fiber optics are due mainly to:

Scattering losses

Absorption losses

Bending losses Splicing loss

Coupling losses

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ATTENUATIONSTANDARDFIBER

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1st window wavelength :0.85 um The lowest minimum loss: 5 to 10 db/km

2nd window 1.30 um 0.5 to 2 dB/km

3rd window 1.55 um 01. to 0.5 dB/km


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FIBREOPTIC - BASICELEMENTS

The main elements are:

Driving circuitry:

Serves as an electrical interface between the inputcircuitry and light source and to drive the light source

Light source

LED / LASER

Convert electrical energy to optical energy, where theamount of light emitted is proportional to the amount ofdrive current

Light source-to-fiber coupler

An interface to couple the light emitted by the sourceinto the optical fibre cable

Fibre optics

Long thin strand of glass or plastic fibre used to signalin a form of light from a point to another point

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FIBRE OPTIC COMMUNICATION SYSTEM

Elements in an optical fibre communication link

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OPTICAL TRANSMISSION MULTIPLEX SYSTEM


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APPLICATIONOFFIBEROPTICCABLE

Some of the applications of fiber optic

Long haul, backbone public and private networks

Local loop networks

Fiber backbone networks (LAN connectivity)

High resolution image and digital video Computer networks, wide area and local area

Shipboard communications

Aircraft communications and controls

Interconnection of measuring and monitoringinstruments in plants and laboratories

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Fiber to the node / neighborhood(FTTN) / Fiber to the cabinet

(FTTCab)

Fiber to the curb (FTTC) / Fibre to the

kerb (FTTK)- Also sometimes called

FTTP for "to the pole", which usage

conflicts with use of the "P" to mean

"to the premises".

Fiber to the building (FTTB) which

does not imply any fiber actually

inside a home.

Fiber to the home (FTTH) which

actually means "into the home" to

internal fiber optic outlets.


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Numerical Aperture

Wavelength

Acceptance angle


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Optical FiberA typical optical fiber is shown in Figure. The fibercore iscompletely encased in a fibercladdingthat has a slightly

lesser value of refractive index. Signals propagate along the

core by total internal reflection at the core-cladding boundary.

f cn n

A cross section of the fiber with rays traced for two

different incident angles is shown. If the phase matching

condition is met, these rays each represent propagating

modes.

The abrupt change in n is a characteristic of a step-index

fiber. Optical fiber designed to support only one

propagating mode is termed single-mode fiber. More

than one mode propagates in multi-mode fiber.

2 2

01

2f c

a n n

k

In step-index optical fiber, a single mode will propagate so long as the

wavelength is big enough such that

where k01 is the first root of the zeroth order

Bessel function, equal to 2.405


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Optical Fiber

For step-index multi-mode fiber, the total number of propagating modes is

approximately

2

2 22

f c

aN n n

Example 7.3: Suppose we have an optical fiber core of index 1.465 sheathed in

cladding of index 1.450. What is the maximum core radius allowed if only one mode

is to be supported at a wavelength of 1550 nm?

01

2 22 f c

ka

n n

2 2

01

2f c

a n n

k

How many modes are supported at this maximum radius for a source wavelength of

850 nm?

9

2 2

2.405 1550 10or 2.84

2 (1.465) (1.450)

x ma a m

2

6

2 2

9

(2.84 10 )2 (1.465) (1.450) 9.6

850 10

x mN

x m

The fiber supports 9 modes!

O i l Fib


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Optical FiberNumerical Aperture

Light must be fed into the end of the fiber to initiate

mode propagation. As Figure shows, upon incidence

from air (no) to the fiber core (nf) the light is refracted

by Snells Law:

FiberLaser Source

sin sino a f b

n n

cos cos 90 sinb c c

2 2sin cos 1

b b

2sin 1 cos

o a f bn n

2

sin 1 sino a f cn n

90 180c b

90b c

The sum of the internal angles in a

triangle is 180 deg.

90

The numerical aperture, NA, is defined as

21 sin

sinf c

a

o

nNA

n

O ti l Fib


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The incident light make an angle c with a normal to

the corecladding boundary. A necessary condition

for propagation is that c exceed the critical angle(i)critical, where

sin ci critf

n

n

2 2

f c

o

n nNA

n

Therefore, the numerical aperture, NA, can bewritten as

21 sin

f c

o

nNA

n

FiberLaser Source

sin ci critf

n

n

O ti l Fib


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Example 7.4: Lets find the critical angle within the fiber described in Example

7.3. Then well find the acceptance angle and the numerical aperture.

1 1.450sin sin 81.8 .

1.465

c

c

f

n

n

2 2

1 (1.465) (1.450)sin 12.1 .

1a

The critical angle is

The acceptance angle

Finally, the numerical aperture is

sin 0.209.a

NA


O ti l Fib


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Optical FiberSignal Degradation

Intermodal Dispersion: Let us consider the case when a single-frequency source (called a

monochromaticsource) is used to excite different modes in a multi-mode fiber. Each mode

will travel at a different angle and therefore each mode will travel at a different propagationvelocity. The pulse will be spread out at the receiving end and this effect is termed as the

intermodal dispersion.

Waveguide Dispersion: The propagation velocity is a function of frequency. The spreading

out of a finite bandwidth pulse due to the frequency dependence of the velocity is termed as

the waveguide dispersion.

Material Dispersion: The index of refraction for optical materials is generally a function of

frequency. The spreading out of a pulse due to the frequency dependence of the refractive

index is termed as the material dispersion.

Attenuation

Electronic Absorption: The photonic energy at short wavelengths may have the right amount

of energy to excite crystal electrons to higher energy states. These electrons subsequently

release energy by photon emission (i.e., heating of the crystal lattice due to vibration).

Vibrational Absorption: If the photonic energy matches the vibration energy (at longer

wavelengths), energy is lost to vibrational absorption.

O ti l Fib


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Optical FiberGraded-Index Fiber

One approach to minimize dispersion in a

multimode fiber is to use a graded index fiber (or

GRIN, for short).

The index of refraction in the core has an

engineered profile like the one shown in Figure.

Here, higher order modes have a longer path to

travel, but spend most of their time in lower index

of refraction material that has a faster propagationvelocity.

Lower order modes have a shorter path, but travel

mostly in the slower index material near the center

of the fiber.

The result is the different modes all propagate

along the fiber at close to the same speed. The

GRIN therefore has less of a dispersion problem

than a multimode step index fiber.


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FIBER LINK BUDGET


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LINK BUDGET

A link budgetis the accounting of all of the gains and

losses from the transmitter, through the medium (freespace, cable, waveguide, fiber, etc.) to the receiver in atelecommunication system.

It accounts for the attenuation of the transmitted signal due topropagation, as well as the antenna gains, feedline andmiscellaneous losses.

Randomly varying channel gains such as fading are taken intoaccount by adding some margin depending on the anticipatedseverity of its effects. The amount of margin required can be reducedby the use of mitigating techniques such as antenna diversity orfrequency hopping, in case of a wireless media.

A simple link budget equation looks like this:

Received Power (dBm) = Transmitted Power (dBm) + Gains(dB) Losses (dB)


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Cable Plant Link Loss Budget Analysis

In fiber optic comm. System, loss budget

analysis is the calculation and verification of

a fiber optic system's operating

characteristics.

This encompasses items such as routing,

electronics, wavelengths, fiber type, and

circuit length.

Attenuation and bandwidth are the key

parameters for budget loss analysis.


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Prior to designing or installing a fiber optic system, a loss

budget analysis is recommended to make certain the system

will work over the proposed link.

Both the passive and active components of the circuit have to

be included in the budget loss calculation.

Passive loss is made up of fiber loss, connector loss, splice

loss, and couplers or splitter loss.

Active components are system gain, wavelength, transmitter

power, receiver sensitivity, and dynamic range.

Prior to system turn up, test the circuit with a source and FO

power meter to ensure that it is within the loss budget.

Analysis of Link Loss In The Design Stage


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The idea of a loss bud get is to insu re the network

equipment w i l l work o ver the instal led f iber opt ic l ink .

It is normal to be cons ervat ive over the specif icat ions!

Don't use the best pos sible specs fo r f iber attenuat ion

or con nector loss - give you rself som e margin!

Analysis of Link Loss In The Design Stage

For example, we have a 2 km multimode link with 5 connections (2

connectors at each end and 3 connections at patch panels in the

link) and one splice in the middle.


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Cable Length 2.0 2.0 2.0

Fiber Type Multimode Single mode

Wavelength (nm) 850 1300 1300 1550

Fiber Atten. dB/km 3 - 3.5 1 -1.5 0.4 -1/0.5 0.3 - 1/0.5

Total Fiber Loss 6.0 - 7.0 2.0 - 3.0

Cable Plant Passive Component Loss

Step 1. Fiber loss at the operating wavelength

(All specs in brackets are maximum values perEIA/TIA 568 standard. For

single mode fiber, a higher loss is allowed for premises applications. )


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Step 2. Connector Loss

Multimode connectors will have losses of 0.2- 0.5 dB typically. Single

mode connectors, which are factory made and fusion spliced havelosses of 0.1- 0.2 dB. Field terminated single mode connectors may

have losses as high as 0.5-1.0 dB.

Let's calculate it at both typical and worst case values.

Connector Loss0.3 dB (typical

adhesive/polish conn)

0.75 dB (TIA-568 max

acceptable)

Total # of Connectors 5 5

Total Connector Loss 1.5 dB 3.75 dB

(All connectors are allowed 0.75 max perEIA/TIA 568 standard)


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Step 3. Splice Loss

Multimode splices are usually made with mechanical splices, although

some fusion splicing is used. The larger core and multiple layers makefusion splicing about the same loss as mechanical splicing, but fusion is

more reliable in adverse environments. 0.1-0.5 dB is for multimode

splices, 0.3 being a good average for an experienced installer. Fusion

splicing of single mode fiber will typically have less than 0.05 dB (that's

right, less than a tenth of a dB!)

Typical Splice Loss 0.3 dB

Total # splices 1

Total Splice Loss 0.3 dB

(All splices are allowed 0.3 max perEIA/TIA 568 standard)


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Best Case TIA 568 Max

850 nm 1300 nm 850 nm 1300 nm

Total Fiber Loss (dB) 6.0 2.0 7.0 3.0

Total Connector Loss (dB) 1.5 1.5 3.75 3.75

Total Splice Loss (dB) 0.3 0.3 0.3 0.3Other (dB) 0 0 0 0

Total Link Loss (dB) 7.8 3.8 11.05 7.05

Step 4. Total Passive System Attenuation

Add the fiber loss, connector and splice losses to get the link loss.

Remember these should be the criteria for testing. Allow +/- 0.2 -0.5dB for measurement uncertainty and that becomes your pass/fail

criterion.


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Equipment Link Loss Budget Calculation:

Link loss budget for network hardware depends

on the dynamic range, the difference between the

sensitivity of the receiver and the output of the

source into the fiber.

You need some margin for system degradation

over time or environment, so subtract that margin

(as much as 3dB) to get the loss budget for thelink.


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Step 5. Data From Manufacturer's Specification for Active

Components (Typical 100 Mb/s link)

Operating Wavelength (nm) 1300

Fiber Type MM

Receiver Sens. (dBm@ required BER) -31

Average Transmitter Output (dBm) -16

Dynamic Range (dB) 15

Recommended Excess Margin (dB) 3

St 6 L M i C l l ti


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Step 6. Loss Margin Calculation

Dynamic Range (dB) (above) 15 15

Cable Plant Link Loss (dB) 3.8 (Type) 7.05 (TIA)

Link Loss Margin (dB) 11.2 7.95

As a general rule, the Link Loss Margin should be greater than

approximately 3 dB to allow for link degradation over time.

LEDs in the transmitter may age and lose power, connectors or splicesmay degrade or connectors may get dirty if opened for rerouting or

testing.

If cables are accidentally cut, excess margin will be needed to

accommodate splices for restoration.


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CRITERIA & CALCULATION FACTORS

Basic Items Used To Determine General

Transmission System Performance

Fiber Loss Factor

Type of fiber

Transmitter

Receiver Sensitivity

Number and type of splices

Margin


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TRANSMISSIONDISTANCECLASSIFICATIONS

Very Short Reach : 300-600 m or less

Short: 2Km

Intermediate: 10-40 Km

Long: 40- 80 Km

Very Long Reach: 120 Km


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EXAMPLE:

Two operation centers are located about 8 miles apart based on

map distance. Assume that the primary communication devices ateach center are a wide area network capable router with fiber opticcommunication link modules, and that the centers are connected bya fiber optic cable. The actual measured distance based on walkingthe route , is a total measured length (including slack coils) of 9miles. There are no additional devices installed along the cable path.

Future planning provides for the inclusion of a freeway managementsystem communication link within 5 years.

Note:

All distance measurements must be converted to kilometers. Fiber

cable is normally shipped with a maximum reel length of 15,000 feet(or 4.5km). 9 miles is about 46,000 feet or 14.5km. Assume that thissystem will have at least 4 mid-span fusion splices.


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From the Table: Fiber Loss Budget Calculation

Fiber Loss: 14.5 km 0.35 dB = -5.075 Fusion splice Loss: 4 0.2 dB = - 0.8

Terminating Connectors: 2 1.0 dB = -2.0

Margin: -5.0

Total Fiber Loss = -12.875

The manufacturer of the router offers threetransmitter/receiver options for single mode fiber:

REACH TRANSMIT POWER RECEIVER SENSITIVITY

Short: -3 dBm -18 dBm

Intermediate: 0 dBm -18 dBm

Long: +3 dBm -28 dBm


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To determine the correct power option add the transmit

power to the fiber loss calculation.

REACH TRANSMIT POWER FIBER LOSS LOSS BUDGET

Short: -3 dBm -12.875 -15.875 dBm

Intermediate: 0 -12.875 -12.875 dBm

Long: +3 dBm -12.875 -9.875 dBm

Compare this to the receiver sensitivity specification

REACH RCVR SENSITIVITY LOSS BUDGET DIFFERENCE

Short: -18 dBm -15.875 +3.0

Intermediate: -18 dBm -12.875 +6.0

Long: -28 dBm -9.875 +19.0


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Because a loss margin of 5.0dB was included in the

fiber loss calculation, the short reach option will

provide sufficient capability for this system.

In fact, the total margin is 8.0db because the

difference between the loss budget and receiver

sensitivity is 3.0 db.


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Problem: Assume a system with the following specifications:

Light transmitter LED output power: 30 W

Light receiver sensitivity: 1 W

Cable Length: 6 km

Cable attenuation: 3 dB/Km, 3X6 = 18 dB total

Four connectors: attenuation 0.8 dB = 3.2 dB total

LED-to-connector loss: 2 dB Cable dispersion: 8 ns/km

Data rate: 3 Mbps

1. Calculate for all the losses.2. What power gain is needed to overcome this loss?

S


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SOLUTION:

First calculate all the losses; add all the dB loss factors.

Total Loss, dB = 18 + 3.2 + 2 + 2 = 25.2 dB

If we add 4-dB contingency factor, making the total loss:

25.2 + 4 = 29.2 dB

What power gain is needed to overcome this loss? dB = 10 log Pt/Pr

where Pt is the transmit power; Pr is the received power

29.2 dB = 10 log Pt/Pr

Pt/Pr = 831.8

Pt = 30/831.8 = 0.036 W


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Note that if the receiver sensitivity is 1 W, 0.036 W is

below the threshold of the receiver.

The problem may be solved in one of the three ways:

Increase transmitter power

1.

Get a more sensitive receiver2. Add repeater.

If the transmitter power is increased to 1 mW or 1000 W:

The Pr= 1000 831.8 = 1.2 W this value is > 1 W


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PERFORMANCE CONSIDERATION:

The performance of a cable is indicated by the bitrate-distance product.

This rating is the fastest bit rate that can be

achieved over a 1 km cable.

R = 1/5dD (s/km)

R maximum data bit rate in Mbps for a given

distance D in Km of the cable with dispersion factor ofd, given in s/km.


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Problem :

A measurement is made on a fiber-optic cable 1200 ft long.

Its upper frequency limit is determined to be 43 Mbps. What

is the dispersion factor D?

1 km = 3274 ft.

D = 1200 ft or 1200/3,274 = 0.367 km

R = 1/5dD

D = 1/5Rd = 1/ [5(43 x 106)(0.367)] = 12.7 ns/km


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HOW TO ESTIMATE TOTAL LINK LOSS

HOW TO ESTIMATE TOTAL LINK LOSS


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Example:

Assume a 40km single mode link at 1310 nm with 2connector pair and 5 splices. Calculate the link loss.


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HOW TO ESTIMATE FIBER DISTANCE

E l


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Example:

Assume a Fast Ethernet Single mode link at 1310nm with 2 connector pairs and 5

splices. Estimate the possible distance of the fiber before dissipating the optical

power to a value below the receiver sensitivity. What are the factors that will

determine the maximum distance of the fiber?


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Fiber Optics Communications System (1)

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