Optical Fiber Basics

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Questions and Answers

What is the primary cause of temporal pulse spreading in optical fibers?

Variation in external light sources

Variation in the length of the fiber

Variation in the velocity of different wavelengths (correct)

Variation in light intensity

What type of dispersion is always present in optical fibers?

Intra-modal dispersion (correct)

Material dispersion

Chromatic dispersion

Intermodal dispersion

Which term refers to the dispersion that occurs within a single mode?

Intermodal dispersion

Chromatic dispersion

Polarization mode dispersion

Intramodal dispersion (correct)

Which type of optical fiber experiences intermodal dispersion?

Multimode step index and graded index fibers Signup and view all the answers

What does 'intermodal' signify in the context of dispersion?

Between different modes Signup and view all the answers

Which factor primarily affects the velocity of light in an optical fiber leading to dispersion?

The wavelength of light Signup and view all the answers

Which statement correctly differentiates between intra- and intermodal dispersion?

Intra-modal is caused by wavelength variation within a mode, intermodal involves different modes. Signup and view all the answers

What is the effect of dispersion on data transmission in optical fibers?

Causes signal overlap and reduces clarity Signup and view all the answers

What is the main disadvantage of multimode fiber compared to single-mode fiber?

Dispersion is more significant. Signup and view all the answers

How does the core diameter of single-mode fiber compare to that of multimode fiber?

It is smaller in single-mode fiber. Signup and view all the answers

What effect does attenuation have on the light signal in optical fibers?

It causes a reduction in signal intensity. Signup and view all the answers

What is the relationship between dispersion and the information transmission capacity of fiber?

Capacity is inversely proportional to dispersion. Signup and view all the answers

Which aspect makes the installation of single-mode fiber more challenging than multimode fiber?

It has a higher installation cost. Signup and view all the answers

What is intramodal dispersion in relation to light travel through optical fibers?

Variation in light pulse spreading within the same mode. Signup and view all the answers

What is the effect of multimode fiber's characteristics on data transmission distance?

It limits information transmission to shorter distances. Signup and view all the answers

Which of the following is a benefit of using single-mode fiber?

No dispersion. Signup and view all the answers

What is the primary cause of microscopic bending loss in optical fibers?

Strains or stresses distributed along the fiber Signup and view all the answers

How can micro-bend losses be minimized in optical fibers?

By extruding a compressible jacket over the fiber Signup and view all the answers

What happens to pulse width after transmission through optical fiber?

The pulse width is consistently expanded Signup and view all the answers

What is the effect of chromatic dispersion in optical fibers?

It spreads a pulse that causes overlap of adjacent pulses Signup and view all the answers

Which types of dispersion are combined to create chromatic dispersion?

Material and waveguide dispersion Signup and view all the answers

What determines the maximum information carrying capacity of an optical fiber?

The broadening of the pulse at the output end Signup and view all the answers

Which statement accurately describes intramodal dispersion?

It results from different speeds of light wavelengths within the same mode Signup and view all the answers

Which of the following factors does NOT contribute to losses in optical fibers?

Well-coated fibers Signup and view all the answers

Study Notes

Optical Fiber Propagation

Optical fibers are flexible structures of glass or plastic, transmitting light over long distances at high speeds.
Light propagates through the fibers using total internal reflection, bouncing off the core-cladding interface.
Key components include:
- Core: The central part of the fiber with a higher refractive index.
- Cladding: The outer material with a lower refractive index that reflects light back into the core.
- Coating: A protective layer around the cladding.
- Jacket: An outer layer that protects the bundled fibers.

Types of Optical Fibers

Step-index fibers:
- Refractive index changes abruptly at the core-cladding interface.
- Multimode step-index fibers support multiple light paths (modes).
- Single-mode step-index fibers support only one mode.
Graded-index fibers:
- Refractive index gradually decreases from the center to the cladding.
- This guides light through a curved path.
- Multimode graded-index fibers support multiple modes but with reduced modal dispersion.

Fiber Characteristics

Numerical Aperture (NA): Measures a fiber's light-gathering ability. A higher NA implies a higher light acceptance.
Attenuation: Loss of light intensity as it travels. Expressed in dB/km.
Dispersion: Spreading of light pulses along the fiber.
- Intermodal dispersion: Occurs in multimode fibers due to different paths light rays take.
- Intramodal (Chromatic) dispersion: Occurs when different wavelengths of light travel at different speeds.

Applications of Optical Fibers

Telecommunications: Transmission of data over long distances.
Medicine: Endoscopy for viewing internal body parts.
Data transmission.
Sensors.

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Description

This quiz covers the fundamental concepts of optical fiber propagation, including its structure and the mechanism of light transmission through fibers. It also explores various types of optical fibers, such as step-index and graded-index fibers. Test your knowledge on fibers and their applications!