Design and Fabrication of Anti-Reflection Thin Films for Fiber Optic Communication Systems

King Fahd University of Petroleum and Minerals Electrical Engineering Department Design and Fabrication of Anti-Reflection Thin Films for Fiber Optic Communication Systems Group E Mansour Al-Hagwi Ahmed Afif Amjad Sindi Rayyan Al-Ghamdi Advisors Dr. H. Masoudi Dr. E. Khawaja Dr. S. Ayub 19 May 2002

In This Presentation • Introduction • Fabrication of Thin Films • Physical Vapor Deposition • Controlling the Thickness • Measurements • Spectrophotometer • Single Layer Anti-Reflection Film (SLAR) • Design and Fabrication • Results • Double Layer Anti-Reflection Film (DLAR) • Design and Fabrication • Results • Inhomogeneous Films • Conclusion

Introduction Transmitted Wave (95.7%) Reflected Wave (4.3%) The aim of the project is to minimize the losses due to reflection Incident Wave Glass Air Fiber Optic

Introduction Transmitted Wave (100%) No Reflection Thin Film Incident Wave Glass Air Fiber Optic

Introduction Anti-Reflection Mechanism: Multi-Reflection • Important Parameters of Thin Films • Refractive index (n) • Thickness of the film (d) Destructive Interference Refractive index n0 Air n1 Film n1 d Glass n2 Thickness Constructive Interference

Fabrication of Thin Films • Physical Vapor Deposition • Need of Vacuum • Approaches • Resistive Heating • Electron Beam • Controlling the Thickness • Quartz Crystal Thickness Monitoring • Optical Thickness Monitoring

Fabrication of Thin Films • Physical Vapor Deposition • Resistive Heating • Apply voltage to the terminals • High current will pass • Temperature increases • Material evaporates in a shape of a cone Coating Material Small Boat Terminals

Fabrication of Thin Films • Physical Vapor Deposition • Electron Beam • High power • Concentration on a small surface Electron Beam e- Filament Pocket

Thickness of the fil m deposite d on the s ubstrate = G Thickness of the fil m deposite d on the q uartz crys tal Fabrication of Thin Films • Controlling the Thickness • Quartz Crystal • Quartz crystal is fixed • Substrate is rotating => Different positions => Different amounts of evaporant => Geometrical Factor (G)

Fabrication of Thin Films • Controlling the Thickness • Optical Thickness Monitoring

Measurements • Dual Beam Spectrophotometer Reflector Detector 1 Reference Beam Slit Light Source Sample Beam Sample Detector 2 Grating Monochromator Splitter

Single Layer Anti-Reflection Films • Design of SLAR • Fabrication of MgF2 Film • Resistive Heating • Quartz Crystal Thickness Monitor Air (n0=1) MgF2 (n1=1.38) Film (n1=1.23) Film (n1) Glass (n2=1.52)

Single Layer Anti-Reflection Films • Results of MgF2 Film RTheoretical = 1.3% RExperimental = 0.7%

Double Layer Anti-Reflection Films • Design of Double Layer Film Air (n0= 1) NdF2 (n1 = 1.6) Film 1 (n1) Film 2 (n2) WO3 (n2 = 2) Glass (n3 = 1.52) • Fabrication of Double Layer Film • Resistive Heating • Optical Thickness Monitor

Double Layer Anti-Reflection Films • Results of Double Layer Film RExperimental = 0.5% RTheoretical = 0.02%

Inhomogeneous Films Region 1 Region 2 => Microscopic view of inhomogeneous films (from literature)

Inhomogeneous Films • Fabrication of CeO2 Film • Electron Beam • Quartz Crystal • Experimental Results RExperimental = 0.1%

Conclusion ? _____ 1.3 0.02 0.7 0.1 0.5 3.5 4.1 3.7

Thank You

Design and Fabrication of Anti-Reflection Thin Films for Fiber Optic Communication Systems