Description : What two properties of the launch condition may affect multimode fiber attenuation measurements?
Last Answer : . Launch spot size and angular distribution.
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 : 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 : 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 : The term single mode and multimode are best described as ∙ A. a number of fibers placed into fiber-optic cable ∙ B. the number of voice channels each fiber can support ∙ C. the number of wavelengths each fiber can support ∙ D. the index number
Last Answer : C. the number of wavelengths each fiber can support
Description : Which are more sensitive to alignment errors, single mode or multimode fibers?
Last Answer : Single mode.
Description : Do small core distortions formed by arc fusion's self alignment mechanism have more of an affect on light propagating through multimode or single mode fibers?
Last Answer : Single mode fibers.
Description : Which semiconductor sources (LD or LED) emit more focused light and are capable of launching sufficient optical power into both single mode and multimode fibers?
Last Answer : LDs.
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 : Multimode step-index fibers have relatively large core diameters and large numerical apertures. These provide what benefit?
Last Answer : Make it easier to couple light from a light-emitting diode (LED) into the fiber.
Description : Multimode step-index fibers have a core and cladding of constant refractive index n1 and n2, respectively. Which refractive index, the core or cladding, is lower?
Last Answer : Cladding.
Description : List the standard core sizes for multimode step-index, multimode graded-index, and single mode fibers
Last Answer : Multimode step-index fibers: 50µm and 100µm. Multimode graded-index fibers: 50µm, 62.5µm, 85µm, and 100µm. Single mode fibers: between 8µm and 10µm.
Description : The number of modes propagated in a multimode fiber depends on core size and numerical aperture (NA). If the core size and the NA decrease, will the number of modes propagated increase or decrease?
Last Answer : Decrease.
Description : Will an optical fiber's attenuation coefficient vary with changes in wavelength?
Last Answer : Yes.
Description : The fiber's normalized frequency (V) determines how many modes a fiber can support. As the value of V increases, will the number of modes supported by the fiber increase or decrease?
Last Answer : Increase.
Description : Why can multimode graded-index fiber 1300-nm systems using LEDs operate over longer distances and at higher bandwidths than 850-nm systems?
Last Answer : Longer distances and higher bandwidths are possible because fiber material losses and dispersion are significantly reduced at the 1300-nm region.
Description : What are the most distinguishing characteristics of a multimode graded-index fiber?
Last Answer : Source-to-fiber coupling efficiency and insensitivity to microbending and macrobending losses.
Description : What multimode graded-index fiber offers the best overall performance for most applications?
Last Answer : 62.5/125 mm multimode graded-index fiber.
Description : Light travels faster in a material with a lower refractive index. Therefore, light rays that travel a longer distance in a lower refractive index travel at a greater average velocity. What effect does this have on multimode graded-index fiber modal dispersion and bandwidth?
Last Answer : Decreases the time difference between light rays, which reduces modal dispersion and increases fiber bandwidth.
Description : What four fiber properties determine the number of modes propagating in a multimode gradedindex fiber?
Last Answer : Numerical aperture (NA), relative refractive index difference ( D), profile parameter (α), and normalized frequency (V).
Description : Does underfilling a multimode optical fiber excite mainly high-order or low-order modes?
Last Answer : Low-order modes.
Description : Modal dispersion affects the bandwidth of multimode systems. It is essential to adjust what three fiber properties to maximize system bandwidth?
Last Answer : Core diameter, NA, and index profile properties.
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 : If the length of the fiber point defect changes with pulse duration, is the OTDR signal deviation a point defect or a region of high fiber attenuation?
Last Answer : A point defect.
Description : Why is a dead-zone fiber placed between the test fiber and OTDR when conducting attenuation measurements?
Last Answer : To reduce the effect of the initial reflection at the OTDR
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 : 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 : What is the basic fiber cleaving technique for preparing optical fibers for coupling?
Last Answer : Score-and-break.
Description : The cutoff wavelength of matched-clad and depressed-clad single mode fibers varies according to the fiber's radius of curvature and length. The cutoff wavelength of which single mode fiber type is more sensitive to length
Last Answer : Depressed-clad.
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 : Band loss is ∙ a. A reduction in transmitter power caused by earth’s surface curvature ∙ b. A reduction in strength of the signal caused by folded dipole bends ∙ c. An attenuation increase caused by bends radiating from the side of the fiber ∙ d. All of these
Last Answer : c. An attenuation increase caused by bends radiating from the side of the fiber
Description : Which type of fiber-optic cable is the best for very high speed data? a. Single-mode step-index b. Multimode step-index c. Single-mode graded-index d. Multimode graded-index
Last Answer : a. Single-mode step-index
Description : Which type of fiber optic cable is most widely used? a. Single-mode step-index b. Multimode step-index c. Single-mode graded-index d. Multimode graded-index
Description : Which of the following is not a common type of fiber-optic cable? a. Single-mode step-index b. Multimode graded-index c. Single-mode graded-index d. Multimode step-index
Last Answer : c. Single-mode graded-index
Description : What type of fiber has the highest modal dispersion? a. Step-index multimode b. Graded index multimode c. Step-index single mode d. Graded index mode
Last Answer : a. Step-index multimode
Description : One of the following is among the types of fiber optics used in electronics communication. A. Step-index multimode B. Graded-index multimode C. Semi-graded multimode D. Single mode
Last Answer : C. Semi-graded multimode
Description : Ho w many times bigger does the bandwidth of a fiber optic multimode have over a cable? A. 50 times bigger B. 100 times bigger C. 10 times bigger D. 5 times bigger
Last Answer : B. 100 times bigger
Description : Type of fiber that has the highest modal dispersion A. Step-index multimode B. Step-index single mode C. Graded index mode D. Graded index multimode
Last Answer : A. Step-index multimode
Description : _____uses short-wave850-nm multimode fiber. A) 10GBase-S B) 10GBase-L C) 10GBase-E D) none of the above
Last Answer : 10GBase-S
Description : In multimode fiber, ____________________ index has less dispersion than step index.
Last Answer : graded
Description : Which type of fiber-optic cable is the most widely used? ∙ A. single-mode step-index ∙ B. multimode step-index ∙ C. single-mode graded index ∙ D. multimode graded index
Last Answer : B. multimode step-index
Description : Which of the following is not a common type of fiber-optic cable? ∙ A. single-mode step-index ∙ B. multimode graded-index ∙ C. single-mode graded-index ∙ D. multimode step-index
Last Answer : . single-mode graded-index
Description : Which type of fiber optic cable is best for very high speed data? ∙ A. single-mode step-index ∙ B. multimode step-index ∙ C. single-mode graded-index ∙ D. multimode graded-index
Last Answer : A. single-mode step-index
Description : Which type of fiber-optic cable has the least modal dispersion? ∙ A. single-mode step-index ∙ B. multimode step-index ∙ C. single-mode graded-index ∙ D. multimode graded-index
Description : A type of index of an optical fiber that has no cladding and whose central core has a non-uniform refractive index. ∙ A. graded index ∙ B. multimode ∙ C. single mode ∙ D. step-index
Last Answer : ∙ A. graded index
Description : A type of index profile of an optical fiber that has a central core and outside cladding with a uniform refractive index ∙ A. multimode ∙ B. graded index ∙ C. step-index ∙ D. single mode
Last Answer : ∙ C. step-index
Description : More than one path for light rays to take down the fiber ∙ A. Multimode ∙ B. Step-index ∙ C. Single mode
Last Answer : A. Multimode
Description : Only one path for light rays to take down the fiber ∙ A. Multimode ∙ B. Step-index ∙ C. Single mode ∙ D. Graded index
Last Answer : C. Single mode
Description : The graded-index multimode optical fiber has a core diameter of _____ nm. ∙ a. 0.5 ∙ b. 0.05 ∙ c. 0.0005 ∙ d. 5
Last Answer : ∙ a. 0.5
Description : A step-index multimode optical fiber has a core diameter of _____ nm. ∙ a. 0.02 ∙ b. 0.2 ∙ c. 2 ∙ d. 0.002
Last Answer : b. 0.2