Optical communications

Chapter 2.1Chapter 2.1

Pham Quang Thai

Pqthai.hcmut@gmail.com

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Content

• Geometrical optics

• Optical propagation in fiber

• Fiber fabrication

• Signal degradation in fiber• Signal degradation in fiber

• Types of fiber

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Think-pair-share

• Broken pencil?

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Think-pair-share

• Broken pencil?

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Think-pair-share

• Bending light

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Think-pair-share

• Guiding light

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Snell’s law

Willebrord van Royen Snell

1580 - 1626

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• Critical angle &

total internal

reflection

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Guiding light using total reflection

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Condition for light to travel inside a

fiber: n1>n2

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Condition for light to enter a fiber:

acceptance angle

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Examples for chapter 2.1

• Problems 2-11:

– Calculate the numerical aperture (NA) of a step

index fiber having n1=1.48 and n2=1.46. What is

the maximum entrance angle θ0max? (nair=1)the maximum entrance angle θ0max? (nair=1)

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