Unit 7.Exercise 1. Fiber Optics--Definitions

Cross Talk- Fiber-optic cabling is immune to crosstalk because optical fiber does not conduct electricity and uses light signals in a glass fiber, rather than electrical signals along a metallic conductor, to transmit data. So it cannot produce a magnetic field and thus is immune to EMI.
Waveguides- A structure that guides electro-magnetic waves along their length. The core fiber in an optical fiber cable is an optical waveguide
FTTH- Fiber to the Home
Simplex- A link that can carry a signal in only one direction
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.
Full Duplex- A system in which signals may be transmitted in two directions at the same time
Photodiode- A component that converts light energy into electrical energy. The photo-diode is used as the receiving end of a fiber optic leak
Amplitude Modulation- A method of signal transmission in which the amplitude of the carrier is varied in accordance with the signal.
Analog Transmission- effected by noise and attenuation more than digital transmission
Digital Transmission- the FCC changed the signal from analog to digital on 12 Jun 2009
Sample Rate- When an analog signal is digitized, any information between the samples is lost, so instead of a smooth transition over time, the digital information jumps from one voltage to the next in the signal. To smooth out the transitions and retain more of the information from the original analog signal
Electro-Magnetic Wave- An alignment of electrical and magnetic fields make up an electro-magnetic field. Refraction- The bending of a beam of light as it enters a medium of different density. Refraction occurs as the velocity of the light changes between materials of two different refractive indexes. Medium- The type of material used to transfer data such as fiber or copper as a medium 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.
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.
Tensile Strength- A type of electrical conductor composed of a number of tiny threads, each having a fine, flat ribbon of copper or other metal closely spiraled about it. Used for small sized cables requiring limpness and extra-long flex life.
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. There are three major types of dispersion: modal, material, and waveguide
Bandwidth- Indicates the transmission capacity of media. For copper cables, bandwidth is defined using signal frequency and specified in hertz (Hz). 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.
Polarity- Identifies which side of an electrical circuit is positive and which is negative.
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.
Scattering- A property of glass that causes light to deflect from the fiber and contributes to losses. (2) The redirection of light caused by atomic structures and particles along the light’s path. See also Rayleigh scattering.
Equilibrium Mode Distribution- Is a condition in which the light traveling through the fiber populates the available modes in an orderly way
Personal Protective Equipment- Personal protective equipment consists of anything that you would wear to protect yourself from materials or situations. PPE can include protective gloves and eyewear for cutting and grinding operations, respirators for working with chemicals that put out harmful vapors, and specialized goggles for working with lasers.

Good Work Habits-
 Keep a clean workspace. Clean up at the end of your work day and store tools properly. A “rat’s nest” can hide problems and add to confusion.
 Observe your surroundings. Look up from what you are doing once in a while to make sure everything around you is the way it should be.  Use tools for the job they were designed to perform. Misuse of tools is one of the most common causes of accidents in the workplace.
 Do not eat or drink in the work area. In addition to accidentally drinking from the wrong bottle, you could accidentally ingest glass fiber or other dangerous materials that might get mixed in with your food.
 Report problems or injuries immediately. Let your facility supervisors know about hazards so they can correct them as soon as possible.
 Know how to reach emergency personnel. Have emergency numbers posted by the nearest telephone so you don’t waste time fumbling through a directory in an emergency.
 Put your emergency contact information in your cell phone.