The Need For More Efficient Electronics The Internet will soon have - - PowerPoint PPT Presentation

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The Need For More Efficient Electronics The Internet will soon have - - PowerPoint PPT Presentation

Apr 01, 2024 1.52k likes •1.73k views

The Need For More Efficient Electronics The Internet will soon have a carbon footprint equivalent to a large industrialized country -The Gaurdian- https://www.theguardian.com/environment/2010/aug/12/carbon-footprint-internet Googles Big

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The Need For More Efficient Electronics

“The Internet will soon have a carbon footprint equivalent to a large industrialized country”

  • The Gaurdian- https://www.theguardian.com/environment/2010/aug/12/carbon-footprint-internet

http://fortune.com/2016/09/30/amazon-google-add-data-centers/

Why Photonics? ØExtremely Low Loss at 1.55 μm for Long Distance communications ØLarge Bandwidth

https://www.merrymesh.com/fiber-optic-cable.html http://www.pngmart.com/image/58330

Information Is Processed with Photonic Devices Google’s Big Data Center

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n1 ncore> ncladding => undergoes total internal reflection and propagates through waveguide Laser Reflected light forms standing wave patterns called modes Fundamental Mode 1st Order Mode

Waveguide Fundamentals

2D Waveguide ncore

Energy Distribution Amplitude

ncladding ncladding

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Waveguide Optical Fiber

Better Efficiency Solutions

1)Reduction of Modal Size Mismatch

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Fiber Vs Semiconductor Waveguide Mode Size

1.0

10 μm 0.5 μm

Field Strength

Fiber Waveguide

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2) Reduce effective index to minimize power reflection

Better Efficiency Solutions

𝚫 =

𝒐𝒇𝒈𝒈%𝒐𝒃𝒋𝒔 𝒐𝒇𝒈𝒈)𝒐𝒃𝒋𝒔 𝟑

𝒐𝑫𝒎𝒃𝒆𝒆𝒋𝒐𝒉 𝒐𝑫𝒑𝒔𝒇 𝒐𝑫𝒎𝒃𝒆𝒆𝒋𝒐𝒉 Waveguide 𝒐𝒇𝒈𝒈 > 𝟐 𝒐𝒃𝒋𝒔 = 1 𝒐𝒇𝒈𝒈 depends upon: Ø 𝒐𝑫𝒑𝒔𝒇 & 𝒐𝑫𝒎𝒃𝒆𝒆𝒋𝒐𝒉 𝒐𝑫𝒎𝒃𝒆𝒆𝒋𝒐𝒉 < 𝒐𝒇𝒈𝒈 < 𝒐𝑫𝒑𝒔𝒇 Ø Waveguide geometry Optical Fiber

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a-Si Waveguide GaAs Waveguide

Waveguide Design using Rsoft BeamPROP

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Mode Profile

GaAs Waveguide

Cross-Sectional View

1.2 μm 0.42 μm 0.65 μm 0.05 μm

Width

GaAs (n = 3.377) AlGaAs (n = 2.939) AlGaAs (n = 2.939)

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Si Substrate

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Taper designed to reduce effective index 𝒐𝒇𝒈𝒈 𝛃 w

GaAs Waveguide

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BCB Upper Cladding (n=1.535) BCB Lower Cladding (n = 1.535)

Si Substrate a-Si

a-Si Waveguide

a-Si Waveguide Cover Material Options 𝒐𝒇𝒈𝒈 𝛃 w

w

Si3N4 Upper Cladding (n=1.91) BCB Lower Cladding (n = 1.535) v

Si Substrate a-Si

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Concept

a-Si Waveguide Fiber Mode profile gradually varies along taper 1.55 μm laser

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a-Si with BCB Cladding Index Matching Results

t = .1μm w = .7μm BCB Upper Cladding (n=1.535) BCB Lower Cladding (n = 1.535) Si Substrate a-Si Neff = 2.076 w = .25μm

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a-Si GaAs

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a-Si with SiN4 Cladding Index Matching Results

a-Si Si3N4 Cladding (n=1.91) BCB Substrate N = 1.535 Neff = 2.287 t = .1μm w = 1.2μm w = .29μm Si Substrate

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a-Si GaAs

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Power Efficiency GaAs a-Si

Removing top two layers of structure

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Conclusions and Future Work

In general, III-V waveguides have tightly confined modes which are undesired. By introducing the tapered design, I have demonstrated a low loss passive coupling interface with a larger mode profile. I have also simulated the coupling loss into the Si waveguide – approximately 3.9dB per coupling interface. By reducing the Si waveguide width further, we can reduce this loss.

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Acknowledgements

Wendy Ibsen (Program Coordinator) Prashanth Bhasker (Graduate Mentor) Jhonattan Ramirez (Post Doctoral Researcher)

  • Dr. Nadir Dagli (Principal Investigator)