Fiber Types

7/28/2019 Fiber Types

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TYPES OF FIBER



0.1

0.2

0.5

1.0

2.0

5.0

10

20

50

100

800600 1200100016001400 1800

Early 1970s

First

Window

Second

Window ThirdWindow

1980s

Wavelen th nm

A t t e n u

a t i o n ( d B / k m

)

EVALUATION



Mostly SM fiber is used long distance communication typically 5 Km

to 170 Km with out any problem

MM fiber is only used for the low data rates and short distance

communication typically 100 meter to 1 Km

Distance of reach depends on so many parameters



Normal Single Mode Fiber

DSF (Dispersion shifted fiber)

NZ-DSF ( dispersion shifted fiber ) DCF (Dispersion compensating fiber)

LEAF (Larger effective area fiber)

DFF (Dispersion Flattened Fiber)



Dispersion is zero at 1312 nm wavelength

At 1312 nm the losses in the fiber is high

While Losses minimum at 1550 nm while the dispersion

parameter is +17 ps/nm/Km



Zero dispersion wavelength (nm)

Cutoff wavelength (nm)

Attenuation (dB/Km)

Dispersion (ps/nm Km)

PMD coefficient (ps/Km1/2)

Mode field diameter (micro meter)

Effective area (micro meter 2)



Parameter at different wavelengths are

Attenuation slope (dB/Km/nm)

Dispersion slope (ps/nm2 Km)

Mode field diameter



1 Attenuation only in fiber (dB/km) 1550 nm ≤0.25

2 Attenuation vs. wavelength (dB/km) 0.05

Max Delta from 1550nm value between (1525-1625 nm)

3 Dispersion slope (ps/nm 2 -km) mean At 1550 (nm) ≤ 0.092

4 Zero dispersion wavelength (nm) 1310 or 15505 Dispersion (ps/nm.km) mean @1550nm (P or N)

1530 to 1565 nm 2.6 to 6.0 P

1565 to 1625 nm 4.5 to 11.2 P

6 Mode field diameter (µm) At 1550 nm 9.2 to 10

7 Max Effective area (µm2) Norminal 72

8 Cutoff Wavelength (nm) 1247

9 PMD Coefficient (ps/km1/2), max mean, @1550 nm ≤0.08

10 Effective Group Index of Refraction @ 1550 nm 1.469



G.650 – Definition and test methods for the relevant

parameters of single mode fibers

G.651 – Characteristics of a 50/125 μm multimode graded

index optical fiber cable

G.652 – Characteristics of a single-mode optical fiber cable

G.653 – Characteristics of a dispersion-shifted single-mode

optical fiber cable.



G.654 – Characteristics of a 1550 nm wavelength loss-

minimized single-mode optical fiber cable

G.655 – Characteristics of a non-zero dispersion single- mode

optical fiber cable.



ITU-recommendation G.652 SMF has

Zero chromatic dispersion at 1310

High chromatic dispersion

(approx. 17ps/nm-km) at 1550nm Advantage

Support WDM

Low in cost Disadvantage

Suitable only for short and medium distances

Needs Dispersion Compensation modules



15501310

D i s p e r s i o n ( p s / n m . K m )

0

-10

-20

10

20

nm

EDFA Gain Spectrum

1530 1610



ITU-recommendation G.653

Wave guide dispersion and material dispersion cancel out each other at1310nm

Same cancellation is used at 1550nm band

The reasons are principally:

Fiber attenuation is a lot lower in the 1550 nm band

Erbium doped fiber amplifiers operate in this band Done by increasing the waveguide dispersion



1550

1310

D i s p e r s i o n ( p s / n m . K

m )

0

-10

-20

10

20

nm

EDFA Gain Spectrum

1530 1610

NDSF

DSF



Advantage

Suitable for DWDM applications, with broad channel

spacing

Dispersion compensation is required after long distances

Disadvantage

Not suitable for higher channel count

Suffers from strong nonlinear effectsUnsuitable for narrow channel spacing, due to four wave

mixing



• ITU-recommendation G.655

• Low positive value of dispersion

(4 ps/nm/km in the 1530-1610 nm band)

• Advantages

• Minimizes unwanted effects Four-Wave-Mixing(FWM)

• More distance than SMF

• Disadvantage

• Not able to carry large optical power




m )

0

-5

-10

5

10

nm

EDFA Gain Spectrum

1530

1610

NZ-DSF

DSF

1550

NZ-DSF



• Here dispersion over range from 1300 to 1700 is reduced i.e 3ps/nm/km

• Advantages

• Very less dispersion change within EDFA spectrum

• Efficient for DWDM systems with less number of channels • Disadvantages

• Extremely high attenuation (2dB/Km)

• Severe Four Wave Mixing problems




m )

0

-10

-20

10

20

nm

EDFA Gain Spectrum

1530 1610

DSF

1550

Dispersion

Flattened



Fiber effective is increased to 72 to 80 micro meter 2 from 50 micro

meter 2

This type of fiber can carry large amount of the optical power

Nonlinear interactions will be reduced

Generally used in Undersea applications

Disadvantage

– Difficult fiber design

– Cost is very high



Fiber Type Properties TargetApplication

NetworkImpact

SMF

NZDSF

LEAF

All-Wave™

RNDF

Standard

Reduced

Dispersion

Reduced Fiber

Non Linearity

Eliminates

Water Peak

Reduced Negative

Dispersion

Common

WDM Long

Haul

WDM Long

Haul

WDM Metro

CWDM

Metro,

Regional

-----------------

Reduced No. of

Regenerators

Reduced No. of

regenerators

Increased No. of

Usable & Low

Cost Components

Reduce DCMs &

Regenerators

Fiber Technologies

Fiber Types

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