Unit 7 Assignments
Physical Networking Unit 7 Assignments
Exercise 1 – Fiber Optics Definitions
1. Crosstalk – The coupling or transfer of unwanted signals from one pair within a cable to another pair. 2. Waveguides – A structure that guides electromagnetic waves along their length. The core fiber in an optical-fiber cable is an optical waveguide. 3. FTTH – Fiber-to-the-home
4. Simplex –
a. A link that can only carry a signal in one direction.
b. A fiber-optic cable or cord carrying a single fiber.
Simplex cordage is mainly used for patch cords and temporary installations 5. Half-Duplex – A system in which signals may be sent in two directions, but not at the same time. In a half-duplex system, one end of the link must finish transmitting before the other end may begin. 6. Full-Duplex – A system in which signals may be transmitted in two directions at the same time. 7. Photodiode – A component that converts light energy into electrical energy. The photodiode is used as the receiving end of a fiber-optic link. 8. Amplitude Modulation – A method of signal transmission in which the amplitude of the carrier is varied in accordance with the signal. With respect to optical fiber cabling, the modulation is done by varying the amplitude of a light wave, common in analog/RF applications. 9. Analog Transmission – a transmission method of conveying voice, data, image, signal or video information using a continuous signal which varies in amplitude, phase, or some other property in proportion to that of a variable. 10. Digital Transmission – The sending of information over a physical communications media in the form of digital signals. 11. Sample Rate – Defines the number of samples per unit of time (usually seconds) taken from a continuous signal to make a discrete signal. 12. Electromagnetic Wave – A wave of energy propagated in an electromagnetic field. 13. Refraction – The bending of a beam of light as it enters a medium of different density. 14. Medium – An intervening substance through which something else is transmitted or carried on. 15. Total Internal Reflection – The reflection of light in a medium of a given refractive index off of the interface with a material of a lower refractive index at an angle at or above the critical angle. Total internal reflection occurs at the core/cladding interface within an optical fiber cable. 16. Fresnel Reflection – Reflection of a small amount of light passing from a medium of one refractive index into a medium of another refractive index. In optical fibers, reflection occurs at the air/glass interfaces at entrance and exit ends. 17. Tensile Strength – Resistance to pulling or stretching forces. 18. Dispersion – A broadening or spreading of light along the propagation path due to one or more factors within the medium (such as optical fiber) through which the light is traveling. 19. Bandwith – Indicates the transmission capacity of media. For optical fiber, wavelength in nanometers (nm) defines bandwidth. Also refers to the amount of data that can be sent through a given channel and is measured in bits per second. 20. Polarity – Identifies which side of an electrical circuit is positive and which is negative. 21. Absorption – The loss of power (signal) in an optical fiber resulting from conversion of optical power (specific wavelengths of light energy) into heat. Caused principally by impurities, such as water, ions of copper or chromium (transition metals), and hydroxyl ions, and by exposure to nuclear radiation. Expressed in dB/km (decibels per kilometer). Absorption and scattering are the main causes of attenuation (loss of signal) of an optical waveguide during transmission through optical fiber.
22. Scattering –
a. A property of glass that causes light to deflect from the fiber and contributes to losses. b. The redirection of light caused by atomic structures and particles along the light’s path. 23. Equilibrium Mode Distribution...
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