Waveguide Fabrication Techniques - NTUAusers.ntua.gr/eglytsis/IO/Waveguide_Fabrication_p.pdf · Fabrication Techniques . General Methods Deposition Techniques • Deposit a higher

Waveguide Fabrication Techniques

Integrated Optics Prof. Elias N. Glytsis

School of Electrical & Computer Engineering National Technical University of Athens

20/12/2016

Optical Waveguides Fabrication Techniques

General Methods Deposition Techniques

• Deposit a higher index thin-film on a lower-index substrate Substitution Techniques • Create a higher index layer in a substrate by introducing new

atoms

A. Boudrioua, “Photonic Waveguides”, J. Wiley & Sons, 2009

General Criteria for Technique Selection • Thickness and Refractive Index of Thin Layer • Losses of the Substrate • Material Purity • Stability of Process and Thin Film • Reproducibility of the technique • Cost

2 Prof. Elias N. Glytsis, School of ECE, NTUA

Dielectric Materials Step-Index (deposition)

• Sputtered-film • Polymer Film Graded-Index (substitution) • Ion Migration • Proton Exchange • Metal In-diffusion • Ion Implantation

Semiconductor Materials Step-Index (deposition)

• Liquid-Phase Epitaxy (LPE) • Vapor-Phase Epitaxy (VPE) • Molecular Beam Epitaxy (MBE) Graded-Index (substitution) • N/A

Planar (Slab) Waveguides

D. L. Lee, “Electromagnetic Principles of Integrated Optics”,J. Wiley & Sons, 1988

Optical Waveguides Fabrication Techniques


Schematic presentation of different types of optical materials



Sputtered-Film Waveguides

D. L. Lee, “Electromagnetic Principles of Integrated Optics”,J. Wiley & Sons, 1988


Principle of thin film deposition by using pulsed laser deposition (PLD)

http://www.andor.com/learning-academy/pulsed-laser-deposition-an-introduction-to-pulsed-laser-deposition



Magnetron sputtering principle


Sputtered-Film Waveguides

https://www.google.gr/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiUz_7IhIPRAhXFNhoKHfq_B-MQjRwIBw&url=http%3A%2F%2Fwww.polymedia.ch%2FOpArticles%2Fview%2F57&psig=AFQjCNFsy5nyjoaluNW4_S_RtEV2y4Yx3g&ust=1482332373425643


Techniques for Polymer Waveguides


Spin Coating

http://www.brewerscience.com/spin-coating-theory

Process Trend Charts


Techniques for Polymer Waveguides

Plasma Polymerization

https://commons.wikimedia.org/wiki/File:Glow_Discharge_apparatus_color.png


Materials for Polymer Waveguides

X. Colin Tong, “Advanced Materials for Integrated Optical Waveguides”, Springer-Verlag, 2014



Some Advanced Materials for Polymer Waveguides


Ion (Proton) Exchange (H+) in Lithium Niobate



Typical index profile of a H+:LiNbO3 (z-cut) waveguide

H+:LiNbO3 (z-cut) thickness variation versus protonic exchange duration for different temperature values


Proton Exchange (H+) in Lithium Niobate


Ti-Indiffusion in Lithium Niobate



Typical temperature profile for titanium diffusion

index profile of a titanium diffusion guide

Ti In-diffusion in Lithium Niobate



Scheme of the Van de Graaff accelerator (300 KeV – 2.2 MeV)


Ion Implantation


Ion Implantation Waveguide Fabrication Process



Effects of implantation on the material refractive index



Ordinary and extraordinary index profiles of LiNbO3 -LiTaO3 waveguide fabricated by He+ implantation

A. Boudrioua, “Photonic Waveguides”, J. Wiley & Sons, 2009 D. L. Lee, “Electromagnetic Principles of Integrated Optics”,J. Wiley & Sons, 1988

dose = 2×1016 ions/cm2 and energy = 2 MeV

LiNbO3 LiTaO3


Semiconductor Waveguides Ga1-xAlxAs System

Controlling Al concentration can engineer band-gap energy

Eg(x) = 1.439 + 1.042x + 0.468x2 (eV)

R. G. Hunsperger, “Integrated Optics”, 6th Ed., Springer-Verlag, 2009


Semiconductor Waveguides GaxIn1-xAsyP1-y System

Eg(y) = 1.35 – 0.775y + 0.149y2 (eV)

x = 0.1894y/(0.4184-0.013y) Lattice match


P. Capper & M. Mauk ,“Liquid Phase Epitaxy”, J. Wiley & Sons, 2007

Liquid Phase Epitaxy (LPE)


Liquid Phase Epitaxy (LPE)


Hydride/Chloride Vapor Phase Epitaxy


Hydride/Chloride Vapor Phase Epitaxy


Metal-Organic Vapor Phase Epitaxy (MOVPE) Metal Organic Chemical Vapor Deposition (MOCVD)


Molecular Beam Epitaxy (MBE)

http://web.tiscali.it/decartes/phd_html/III-Vms-mbe.png


Epitaxial Growth Example

Blue laser diodes grown by MBE

SEM image showing fabricated laser.

Gold contact

M. Kauer et al. “InGaN laser diodes fabricated by molecular beam epitaxy”


Epitaxial Growth Example Violet Laser Diodes Grown by MBE

F. Heffermann et al, Phys. Stat. Sol. (a) 201, No. 12, 2688–2671 (2004) / DOI 10.1002/pssa.200405034


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Waveguide Fabrication Techniques - NTUAusers.ntua.gr/eglytsis/IO/Waveguide_Fabrication_p.pdf · Fabrication Techniques . General Methods Deposition Techniques • Deposit a higher