Understanding Fiber Optics - Specjalizowane przyrządy i ... · PDF fileUnderstanding Fiber...
Transcript of Understanding Fiber Optics - Specjalizowane przyrządy i ... · PDF fileUnderstanding Fiber...
Understanding Fiber Optics
Snell's LawSnell's Law
F. O. Communication SystemF. O. Communication System
Fiber Optics ConnectorsFiber Optics Connectors
Applications of F. O.Applications of F. O.
Multimode, Step-Index
Multimode, Graded-Index
Single mode
=n1 sin
sinn2
θ2
θ1
T h e a n g l e o f incidence φ and 1
refraction φ are 2
related to each other and to refractive indices of dielectrics by Snell's Law of Refraction which states that :
WDM Optical SystemWDM Optical SystemTotal Internal ReflectionTotal Internal Reflection
In 1870, , demonstrated that light used internal reflection to follow a specific path.? , in 1880, patented a method of light transfer called “piping light.”? developed an optical voice transmission system he called the photophone.?Fiber optic technology experienced a phenomenal rate of progress in the second half of the twentieth century.?
History History
Light Reflectedfrom surface
Light Gradually
Leaks OutWater
Flowing Out of Basin
Multimode Single mode
Cables
John Tyndall
William Wheeling
Alexander Graham Bell
The Arrival of Optical Revolution
10000
1000
100
10
1
0.1Year
Commercial System
Research Results
TDM CommericalWDM CommercialTDM ResearchWDM Research
1985 1990 1995 2000
Capa
city
/(GB/
s) WDM
Buffer
Core
Cladding
The simplest fiber optic cable consists of two concentric layers of transparent materials. The inner portion (the core) transports the light; the outer covering (the cladding) must have a lower refractive index than the core so the two are made of different materials.To provide mechanical protection for the cladding an additional plastic layer; the Primary Buffer is added. Some constructions of optic fiber have additional layers of buffer, which are then referred to as Secondary Buffer. It is very important to note that the whole fiber Core, Cladding & Primary Buffer is solid and the light is confined to the core by the Total Internal Reflection due to the difference in the refractive index of the core compared to that of cladding.
F.O. Cable ConstructionF.O. Cable Construction
Refractive Indexing MaterialRefractive Indexing Material
Transmitter Receiver
200 meters
Applications - Networks
Applications - Links
l l ll Telecom SONET ATM DWDM l l Fiber Amps CATVl lll AM vs FM vs Digital HFC LANs Ethernetl lll l Token Ring FDDI SANs ESCON Fiber Channel
l l l l Video Security Broadcast TV Industrial Linksl l l RS-232 RS-422 Wireless Antennasl l Utility grid management Sensors
∆ = 25 - 100 GHz(0.4 or 0.8 nm @ 1500 nm)
λ
Optical Fiber
40 - 120 km
Up to 10,000 km
R
R
R
R
Frequency-registeredtransmitters Receivers
WDMMux Amp Amp WDM
DeMux
λ1
λ2
λ3
λN
Numerical Aperture & Acceptance AngleNumerical Aperture & Acceptance Angle
N. A.= (n ) - (n )1 2
1975 : Coax, 274 Mb/s at 1km repeater spacing1980 : 0.8 um GaAs lasers, MMF, 45 Mb/s @10km1987 : 1.3 um InGaAsP lasers, SMF, 1.7 Gb/s @50km1990s : 1.55 um InGaAsP DFB lasers, SMF, 2.5-10 Gb/s @ 40km1990s : WDM, 1.55 um InGaAsP DFB lasers, EDFA, SMF,
2.5-10 Gb/s @ 300-10,000km repeater spacing2002 : 64 WDM chx 10Gbps over 250,000 km span
Lightwave EvolutionLightwave Evolution
Fastmedium(smallerindex ofrefraction)
θ1
θ2
SlowMedium
n1 n2
Low index n2
(Air)
High index n1
(Glass)Partial internalreflection
Incident ray
Exit ray
φ1
φ2
CladdingCore
Acceptance Angle
Acceptance Cone
Connector Insertion Loss Repeatability Fiber Type Applications
0.50-1.00 dB 0.20 dB SM, MM
0.20-0.70 dB 0.20 dB SM, MM
0.15 db (SM)0.10 dB (MM) 0.2 dB SM, MM
0.30-1.00 dB 0.25 dB SM, MM
0.20-0.45 dB 0.10 dB SM, MM
0.20-0.45 dB 0.10 dB SM, MM
FC
LC
SC
ST
SM, MM
Typ. 0.40 dB(SM)
Typ. 0.50 dB(MM)
Typ. 0.40 dB(SM)
Typ. 0.20 dB(MM)
Fiber OpticNetwork
High DensityInterconnection
High DensityInterconnection
Datacom
Datacom
Inter-/Intra-Building,
Security, Navy
Datacom,Telecommuni-
cations
FDDI
MT Array
SC Duplex
Sugar solution (80%)
StrengtheningFibersCore Cladding Coating
Cable Jacket
Vacuum 1.00000Air at STP 1.00029Ice 1.31Water at 20°C 1.33Acetone 1.36Ethyl alcohol 1.36Glycerine 1.473 1.49
Glass 1.5Sodium chloride 1.54Polystyrene 1.55Flint glasses 1.57-1.75Extra dense flint,EDF-3 1.7200 Diamond 2.417Sapphire 1.77
Output Input TransmitterOptical Comm.
ChannelOptical
Receiver
Transmitter Produces and encodes the light signals.
Optical Fiber Conducts the l ight s igna ls over a distance.
Optical Regenerator May be necessary to boost the light signal (for long distances).
l Format l Bandwidth l Protocol l Modulation l Characteristics l Power l Wavelength
l Loss l Dispersion l 4-Wave Mixing l Noisel Crosstalks l Distortion l Amplification
l Bandwidth l Responsivityl Sensitivity l Noise l Wavelength
Fiber is deployed at a rate of 2000 miles every hour.
Losses in F. O.Losses in F. O.1. Attenuation2. Material Absorption Losses 3. Linear Scattering Losses
a. Ray Leigh Scatter b. Mie Scattering4. Non Linear Scattering5. Micro Bending and Macro Bending 6. Dispersion
a. Intermodal Dispersion b. Intramodal Dispersion
F. O. ComponentsF. O. ComponentsTransmitterReceiver
ll- LEDs Laser Diodes l l- PIN Diodes APDs
lCableslConnectors lSplicesl Amplifiersl Hardware (Installation hardware, patch panels,
splice closures, conduit and innerduct, etc.)
Disadvantage of F. O.Disadvantage of F. O.?
The lack of standardization.?More difficult and expensive to splice than wires.?
Fiber optic components are expensive.
?and capacity.Lower signal attenuation (loss)?Immunity to Electrical Noise?Immune to noise ?(electromagnetic interference [EMI] and radio frequency interference [RFI]No crosstalk?Lower bit error rates?Signal Security?Difficult to tap?Nonconductive ?(does not radiate signals) Electrical IsolationNo common ground required?
Greatly increased bandwidth ?short circuit and sparks.Size and Weight?Environmental Protection?Resistant to radiation and ?corrosion.Resistant to temperature ?variations.Improved ruggedness and ?flexibility.Less restrictive in harsh ?environments.Overall System Economy?Low per-channel cost?Lower installation cost?
Freedom from
Advantages of F. O.Advantages of F. O.
62.5 / 125 microns
Core Cladding
+Scientech Technologies Pvt. Ltd. 90 Electronic Complex, Pardesipura, Indore- 452010, lndia. 91-731- 4511100, [email protected] www.ScientechLearning.com
Learning