1. Optical fibers primarily use which principle to transmit light?
Answer:
Explanation:
Optical fibers transmit light based on the principle of total internal reflection, where light is confined within the core of the fiber due to the refractive index difference between the core and the cladding.
2. The main advantage of optical fiber communication over copper wire communication is:
Answer:
Explanation:
Optical fiber communication provides significantly higher data transmission speeds compared to copper wire communication, along with greater bandwidth and lower signal attenuation.
3. The component in an optical communication system that converts electrical signals to light signals is called a:
Answer:
Explanation:
A laser diode in an optical communication system converts electrical signals into light signals. It emits light through stimulated emission of radiation and is more efficient than LEDs for high-speed communication.
4. In optical communication, the loss of signal strength as light travels through the fiber is known as:
Answer:
Explanation:
Attenuation in optical fibers refers to the reduction in signal strength as light propagates through the fiber, mainly due to absorption and scattering losses.
5. Chromatic dispersion in optical fibers is caused by:
Answer:
Explanation:
Chromatic dispersion in optical fibers occurs due to the variation in the speed of light propagation for different wavelengths, leading to broadening of pulses over distance.
6. An optical amplifier is used in fiber optic communication to:
Answer:
Explanation:
Optical amplifiers boost the strength of light signals directly, without the need for conversion to electrical signals, allowing for longer transmission distances without significant signal loss.
7. Single-mode fiber is typically used for:
Answer:
Explanation:
Single-mode fibers, with their small core diameter, are used for long distance communication as they allow light to travel straight down the fiber, minimizing signal loss and dispersion.
8. The principle of Wavelength Division Multiplexing (WDM) involves:
Answer:
Explanation:
Wavelength Division Multiplexing (WDM) is a technique in optical communication that combines multiple light signals on a single fiber by using different wavelengths (colors) for each signal, significantly increasing the capacity.
9. The purpose of cladding in an optical fiber is to:
Answer:
Explanation:
The cladding in an optical fiber, having a lower refractive index than the core, reflects light back into the core, enabling total internal reflection and preventing light from escaping the fiber.
10. A Photodetector in an optical communication system is used to:
Answer:
Explanation:
Photodetectors in optical communication systems are used to convert incoming light signals back into electrical signals, enabling the reception and processing of the transmitted information.
11. The term 'fiber optic bandwidth' refers to:
Answer:
Explanation:
Fiber optic bandwidth refers to the data carrying capacity of the optical fiber, which is the amount of data that can be transmitted per unit of time, typically measured in gigabits per second (Gbps).
12. In optical fiber communication, Raman scattering is:
Answer:
Explanation:
Raman scattering in optical fibers is a phenomenon where some of the light signal energy is scattered due to the interaction with the fiber material, causing signal loss.
13. An 'optical coupler' in fiber optic systems is used to:
Answer:
Explanation:
Optical couplers are devices used in fiber optic systems either to combine light signals from multiple fibers into a single fiber or to split a light signal from one fiber into multiple paths.
14. Dense Wavelength Division Multiplexing (DWDM) is used in optical communication to:
Answer:
Explanation:
Dense Wavelength Division Multiplexing (DWDM) is a technology that increases the transmission capacity of optical fibers by using closely spaced wavelengths, allowing more data to be transmitted simultaneously.
15. The primary reason for using an erbium-doped fiber amplifier (EDFA) in optical communication is to:
Answer:
Explanation:
An erbium-doped fiber amplifier (EDFA) is used in optical communication to amplify light signals and compensate for signal losses over long distances, allowing for extended reach without the need for electrical repeaters.
16. In optical communication, 'modal dispersion' is a phenomenon that occurs in:
Answer:
Explanation:
Modal dispersion is a type of signal distortion that occurs in multi-mode fibers, caused by the different propagation modes of light traveling at different speeds, leading to signal broadening.
17. The 'numerical aperture' of an optical fiber is a measure of:
Answer:
Explanation:
The numerical aperture of an optical fiber is a measure of its ability to gather light and confine it within the core. It is determined by the refractive indices of the core and cladding.
18. Polarization mode dispersion (PMD) in optical fibers is:
Answer:
Explanation:
Polarization mode dispersion (PMD) is a form of signal distortion affecting the quality of signals in high-speed optical communication systems. It arises from the different polarization states of light traveling at slightly different speeds.
19. A 'fiber Bragg grating' in an optical fiber is used for:
Answer:
Explanation:
A fiber Bragg grating is a structure within an optical fiber that reflects specific wavelengths of light while transmitting others. It is used for wavelength filtering and stabilizing laser outputs.
20. The primary use of optical fiber in telecommunications is for:
Answer:
Explanation:
Optical fiber is predominantly used in telecommunications for high-speed, long-distance data transmission, owing to its low attenuation and high bandwidth capabilities.
21. Dispersion compensation in optical fibers is necessary to:
Answer:
Explanation:
Dispersion compensation is crucial in optical fibers to correct signal distortion caused by different types of dispersion, such as chromatic and polarization mode dispersion, ensuring signal integrity over long distances.
22. The main purpose of an optical circulator in fiber optic systems is to:
Answer:
Explanation:
An optical circulator is a non-reciprocal device used in fiber optic systems to direct light signals in a unidirectional way, allowing them to be routed from one port to another sequentially.
23. The 'cut-off wavelength' of an optical fiber refers to:
Answer:
Explanation:
The cut-off wavelength of an optical fiber is the minimum wavelength below which the fiber supports only a single propagation mode (single-mode operation) and higher-order modes are cut off.
24. An optical isolator in fiber optic communication is used to:
Answer:
Explanation:
An optical isolator is used in fiber optic communication to prevent undesired back reflections of light from returning to the optical source, which can cause interference and destabilize the source.
25. Which component in a fiber optic system is used to join two optical fibers end-to-end?
Answer:
Explanation:
Fiber optic connectors are used in fiber optic systems to join two optical fibers end-to-end, allowing light to pass from one fiber into another with minimal loss.