Description : Delay differences between the source wavelengths occur as the optical signal propagates along the fiber. What is this called?
Last Answer : Differential group delay t(l).
Description : The mode theory uses electromagnetic wave behavior to describe the propagation of the light along the fiber. What is a set of guided electromagnetic waves called?
Last Answer : Modes of the fiber.
Description : In multimode step-index fibers, the majority of light propagates in the fiber core for what reason?
Last Answer : Most modes in multimode step-index fibers propagate far from cutoff.
Description : A light ray incident on the optical fiber core is propagated along the fiber. Is the angle of incidence of the light ray entering the fiber larger or smaller than the acceptance angle
Last Answer : Smaller.
Description : A mode filter is a device that attenuates specific modes propagating in the core of an optical fiber. What mode propagating along single mode fibers do mode filters eliminate?
Last Answer : Second-order mode.
Description : Low-order and high-order modes propagate along an optical fiber. How are modes determined to be low-order or high order modes?
Last Answer : Depends on the bending caused by the velocity difference of the wave traveling through different mediums
Description : Light propagates in multimode graded-index fibers according to refraction and total internal reflection. When does total internal reflection occur?
Last Answer : When the angle of incidence becomes larger than the critical angle of incidence.
Description : In electromagnetic waves, the electric field will be perpendicular to which of the following? a) Magnetic field intensity b) Wave propagation c) Both H and wave direction d) It propagates independently
Last Answer : c) Both H and wave direction
Description : Describe an optical fiber cable component (OFCC).
Last Answer : OFCCs are tight-buffer fiber surrounded by arimid yarn and a low-halogen outer jacket.
Description : The index of refraction measures the speed of light in an optical fiber. Will light travel faster in an optically dense material or in one that is less dense?
Last Answer : Light will travel faster in an optical material that is less dense.
Description : What is the basic optical-material property relevant to optical fiber light transmission?
Last Answer : The index of refraction.
Description : A light wave can be represented as a plane wave. What three properties of light propagation describe a plane wave?
Last Answer : Direction, amplitude, and wavelength of propagation
Description : Which type of fiber optic connector (butt-jointed or expanded beam) brings the prepared ends of two optical fibers into close contact?
Last Answer : Butt-jointed connectors.
Description : Give two reasons why optical fiber manufacturers depart from the traditional circular core and cladding, low-loss glass fiber design?
Last Answer : To increase performance and reduce cost
Description : List the two principal optical detectors used in fiber optic systems.
Last Answer : The semiconductor positive-intrinsic-negative (PIN) photodiode and avalanche photodiode (APD).
Description : Which type of optical splitter (Y-coupler or T-coupler) splits only a small amount of power from the input fiber to one of the output fibers?
Last Answer : T-coupler
Description : What is the basic fiber cleaving technique for preparing optical fibers for coupling?
Last Answer : Score-and-break.
Description : Quality fiber-end preparation is essential for proper system operation. What properties must an optical fiber-end face have to ensure proper fiber connection?
Last Answer : Be flat, smooth, and perpendicular to the fiber axis.
Description : Which types of LEDs are the preferred optical sources for short-distance, low-data-rate fiber optic systems?
Last Answer : SLEDs and ELEDs.
Description : The amount of optical power coupled into an optical fiber depends on what four factors?
Last Answer : (1) The angles over which the light is emitted. (2) The size of the source's light-emitting area relative to the fiber core size. (3) The alignment of the source and fiber. (4) The coupling characteristics of the fiber (such as the NA and the refractive index profile)
Description : Which part of a fiber optic transmitter converts the processed electrical signal to an optical signal?
Last Answer : The optical source.
Description : Multimode optical fibers can have a step-index or graded index refractive index profile. Which fiber, multimode step-index or multimode graded-index fiber, usually performs better?
Last Answer : Multimode graded-index fiber
Description : If an installed optical fiber cable does not have connectors or terminations on both ends, how should the cable be tested?
Last Answer : With an OTDR unless it is less than 50 meters in length. If it is less than 50 meters in length, continuity should be verified with a flashlight.
Description : When is an optical power meter measurement recommended for conducting field measurements on installed optical fiber cables or cable plants?
Last Answer : When an installed optical fiber cable or cable plant is less than 50 meters in length.
Description : optical launch conditions exists if the launch spot size and angular distribution are larger than that of the fiber core?
Last Answer : Overfilled.
Description : Does underfilling a multimode optical fiber excite mainly high-order or low-order modes?
Last Answer : Low-order modes.
Description : What are the main causes of absorption in optical fiber?
Last Answer : Intrinsic and extrinsic material properties.
Description : What type of optical fiber operates below the cutoff
Last Answer : The order of a mode is indicated by the number of field maxima within the core of the fiber. The order of a mode is also determined by the angle that the wavefront makes with the axis of the fiber
Description : List the three parts of an optical fiber.
Last Answer : Core, cladding, and coating or buffer.
Description : Which type of optical fiber (multimode or single mode) tends to have lower loss and produces less signal distortion?
Last Answer : Single mode fiber.
Description : In 1969, what did several scientists conclude about optical fiber loss?
Last Answer : mpurities in the fiber material caused the signal loss in optical fibers. The basic fiber material did not prevent the light signal from reaching the end of the fiber.
Description : What mechanisms in the fiber waveguides weaken and distort the optical signal?
Last Answer : Scattering, absorption, and dispersion.
Description : What are the two methods used by fiber manufacturers to fabricate multimode and single mode glass fibers?
Last Answer : Vapor phase oxidation and direct-melt process.
Description : As the core and cladding modes travel along the fiber, mode coupling occurs. What is mode coupling?
Last Answer : Mode coupling is the exchange of power between two modes.
Description : A wavefront undergoes a phase change as it travels along the fiber. If the wavefront transverses the fiber twice and is reflected twice and the total phase change is equal to 1/2 p, will the wavefront disappear? If yes, why?
Last Answer : Yes, the wavefront will disappear because the total amount of phase collected must be an integer multiple of 2 p. (If the propagating wavefronts are out of phase, they will disappear. ... interfere with the wavefronts out of phase. This type of interference is called destructive interference.)
Description : A dielectric waveguide for the propagation of electromagnetic energy at light frequencies a. Stripline b. Microstrip c. Laser beam d. Fiber optics
Last Answer : d. Fiber optics
Description : ________ dispersion is caused by the difference in the propagation times of light rays that take different paths down a fiber. a. Material dispersion b. Wavelength dispersion c. Modal dispersion d. Delay dispersion
Last Answer : c. Modal dispersion
Description : ECE Board Exam November 1996 The loss in signal power as light travels down a fiber is A. attenuation B. propagation C. absorption D. scattering
Last Answer : A. attenuation
Description : The loss in signal power as light travels down the fiber is called ............. A) Attenuation B) Propagation C) Scattering D) Interruption
Last Answer : A) Attenuation
Description : It is caused by the difference in the propagation time of light rays that take different paths down the fiber. ∙ A. modal dispersion ∙ B. microbending ∙ C. Rayleigh scattering ∙ D. chromatic dispersion
Last Answer : A. modal dispersion
Description : A dielectric waveguide for the propagation of electromagnetic energy at light frequencies ∙ a. Stripline ∙ b. Microstrip ∙ c. Laser beam ∙ d. Fiber optics
Description : ______ dispersion is caused by the difference in the propagation times of light rays that take different paths down a fiber. ∙ a. Material dispersion ∙ b. Wavelength dispersion ∙ c. Modal dispersion
Last Answer : ∙ c. Modal dispersion
Description : What condition causes a light ray to be totally reflected back into its medium of propagation?
Last Answer : Total internal reflection occurs when the angle of refraction approaches 90 degrees. This condition occurs when the angle of incidence increases to the point where no refraction is possible.
Description : Describe the operation of an optical detector
Last Answer : It is a transducer that converts an optical signal into an electrical signal. It does this by generating an electrical current proportional to the intensity of incident optical radiation.
Description : Describe the -3 decibel (dB) optical power frequency (f3dB).
Last Answer : The -3 decibel (dB) is the lowest frequency at which the magnitude of the fiber frequency response has decreased to one half its zero-frequency value.
Description : Define the loss in optical power through a connection.
Last Answer : loss = 10log
Description : What happens to light in optical fiber ?
Last Answer : Full optical reflection of light occurs in optical fiber.
Description : What is a specific path the light takes in an optical fiber corresponding to a certain angle and number of reflection a. Mode b. Grade c. Numerical Aperture d. Dispersion
Last Answer : a. Mode