Design and Fabrication of Anti-Reflection Thin Design and Fabrication of Anti-Reflection Thin

Films for Fiber Optic Communication SystemsFilms for Fiber Optic Communication Systems

Advisors

Dr. H. Masoudi

Dr. E. Khawaja

Dr. S. Ayub

Group E

Mansour Al-Hagwi

Ahmed Afif

Amjad Sindi

Rayyan Al-Ghamdi

King Fahd University of Petroleum and Minerals

Electrical Engineering Department

19 May 2002

In This PresentationIn This Presentation

IntroductionIntroduction

Fabrication of Thin FilmsFabrication of Thin Films Physical Vapor DepositionPhysical Vapor Deposition Controlling the ThicknessControlling the Thickness

MeasurementsMeasurements SpectrophotometerSpectrophotometer

Single Layer Anti-Reflection Film (SLAR)Single Layer Anti-Reflection Film (SLAR) Design and FabricationDesign and Fabrication ResultsResults

Double Layer Anti-Reflection Film (DLAR)Double Layer Anti-Reflection Film (DLAR) Design and FabricationDesign and Fabrication ResultsResults

Inhomogeneous FilmsInhomogeneous Films

ConclusionConclusion

IntroductionIntroduction

Fiber Optic

Incident Wave

Reflected Wave (4.3%)Transmitted Wave (95.7%)

Glass Air

The aim of the project is to The aim of the project is to minimize the losses minimize the losses

due to reflectiondue to reflection

IntroductionIntroduction

Fiber Optic

Incident Wave

No ReflectionTransmitted Wave (100%)Thin

FilmGlass Air

n0

n1

n2

IntroductionIntroduction

Anti-Reflection Mechanism: Multi-Reflection

Glass

Film

Air

Destructive Interference

Constructive Interference

n1

Refractive index

Thickness

d

Important Parameters of Thin FilmsImportant Parameters of Thin Films

Refractive index (Refractive index (nn))

Thickness of the film (Thickness of the film (dd))

Physical Vapor DepositionPhysical Vapor Deposition

Need of VacuumNeed of Vacuum

ApproachesApproachesResistive HeatingResistive Heating

Electron BeamElectron Beam

Controlling the ThicknessControlling the Thickness

Quartz Crystal Thickness MonitoringQuartz Crystal Thickness Monitoring Optical Thickness MonitoringOptical Thickness Monitoring

Fabrication of Thin FilmsFabrication of Thin Films

Fabrication of Thin FilmsFabrication of Thin Films

Physical Vapor DepositionPhysical Vapor Deposition

Resistive HeatingResistive Heating

Apply voltage to the terminalsApply voltage to the terminals

High current will passHigh current will pass

Temperature increases Temperature increases

Material evaporates Material evaporates in a shape of a conein a shape of a cone

Small Boat

Terminals

Coating Material

Fabrication of Thin FilmsFabrication of Thin Films

Physical Vapor DepositionPhysical Vapor Deposition

Electron BeamElectron Beam

High powerHigh power

Concentration on Concentration on a small surfacea small surface

PocketFilament

Electron Beam

e-

Fabrication of Thin FilmsFabrication of Thin Films

Controlling the ThicknessControlling the Thickness

Quartz CrystalQuartz Crystal

Quartz crystal is fixedQuartz crystal is fixed

Substrate is rotatingSubstrate is rotating

=> => Different positionsDifferent positions

=>=> Different amounts of evaporant Different amounts of evaporant

=>=> Geometrical Factor ( Geometrical Factor (GG))

taluartz crysd on the qm depositeof the filThickness

ubstrate d on the sm depositeof the filThickness G

Fabrication of Thin FilmsFabrication of Thin Films

Controlling the ThicknessControlling the Thickness

Optical Thickness MonitoringOptical Thickness Monitoring

MeasurementsMeasurements

Dual Beam SpectrophotometerDual Beam Spectrophotometer

Light SourceSlit

Grating Monochromator

Sample

Splitter

Reflector

Detector 2

Detector 1Reference Beam

Sample Beam

1011 ,nngg

γgggg

ggnnT

2cos21

)1()1)(/(

2122

21

22

2102

Single Layer Anti-Reflection FilmsSingle Layer Anti-Reflection Films

Design of SLARDesign of SLAR

Fabrication of MgFFabrication of MgF22 Film Film

Resistive HeatingResistive Heating

Quartz Crystal Thickness Quartz Crystal Thickness MonitorMonitor

41

dn

201 nnn

Film (n1)

Glass (n2=1.52)

Air (n0=1)

4

2122 ,nngg

dn12

MgF2 (n1=1.38)Film (n1=1.23)

Single Layer Anti-Reflection FilmsSingle Layer Anti-Reflection Films

Results of MgFResults of MgF22 Film Film

RExperimental = 0.7%

RTheoretical = 1.3%

Double Layer Anti-Reflection FilmsDouble Layer Anti-Reflection Films

Design of Double Layer FilmDesign of Double Layer Film

0

3

1

2

n

n

n

n WO3 (n2 = 2)

Glass (n3 = 1.52)

(n0 = 1)Air

NdF2 (n1 = 1.6)4

4

Fabrication of Double Layer FilmFabrication of Double Layer Film

Resistive HeatingResistive Heating

Optical Thickness MonitorOptical Thickness Monitor

Film 1 (n1)

Film 2 (n2)23.1

1

2 n

n

Double Layer Anti-Reflection FilmsDouble Layer Anti-Reflection Films

Results of Double Layer FilmResults of Double Layer Film

RTheoretical = 0.02%

RExperimental = 0.5%

Inhomogeneous FilmsInhomogeneous Films

Microscopic view of inhomogeneous films (from literature)

Region 1

Region 2

=>=>=>=>

Inhomogeneous FilmsInhomogeneous Films

0

5

10

15

20

25

0.7 0.8 0.9 1 1.1 1.2 1.3

Normalized Wavelength

Ref

lect

ance

(%

)

Fabrication of CeOFabrication of CeO22 Film Film

Electron BeamElectron Beam Quartz CrystalQuartz Crystal

Experimental ResultsExperimental Results

RExperimental = 0.1%

ConclusionConclusion

Uncoated Glass

Single Layer Films Double Layer Film

Material _____ MgF2 CeO2 NdF2 + WO3

Theoretical Reflectance (%)

4.3

Experimental Reflectance (%)

4.2

Improvement in Reflectance (%)

_____

1.3

0.7

3.5

_____

0.1

4.1

0.02

0.5

3.7??

Thank YouThank YouThank YouThank You