Description : The profile parameter (α) determines the shape of the multimode graded-index core's refractive index profile. As the value of the aincreases, how does the core's profile change?
Last Answer : From a triangular shape to step.
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 : How does index matching gel affect the amount of coupling loss caused by (a) fiber separation, (b) lateral misalignment, and (c) angular misalignment?
Last Answer : (a) Reduces coupling loss, (b) does not change coupling loss, and (c) increases coupling loss
Description : What connection properties result in fiber optic connector coupling loss?
Last Answer : Poor fiber alignment and end preparation, fiber mismatches, and Fresnel reflection.
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 : It is a graphical representation of the magnitude of the refractive index across the fiber. ∙ A. mode ∙ B. index profile ∙ C. numerical aperture ∙ D. refractive index
Last Answer : B. index profile
Description : Describe the term "refractive index profile."
Last Answer : Refractive index profile describes the value of refractive index as a function of radial distance at any fiber diameter.
Description : Reduction of Fresnel reflection is possible by reducing the step change in the refractive index at the fiber interface. What material reduces the step change in refractive index at a fiber interface?
Last Answer : Index matching gel.
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 : The refractive index of a fiber core is uniform and undergoes an abrupt change at the corecladding boundary. Is this fiber a step-index or graded-index fiber?
Last Answer : graded-index fiber?
Description : Is coupling loss from fiber separation and lateral misalignment more critical in expanded-beam or butt-jointed connectors?
Last Answer : Butt-jointed connectors.
Description : Fiber-to-fiber coupling loss is affected by intrinsic and extrinsic coupling losses. Can intrinsic coupling losses be limited by limiting fiber mismatches?
Last Answer : Yes.
Description : Will fiber coupling loss generally increase or decrease if the mode field diameter of a single mode fiber is decreased?
Last Answer : Increase.
Description : While coupled power and bending loss favor a high D, which Dvalue, smaller or larger, improves fiber bandwidth?
Last Answer : Smaller.
Description : What is the refractive index of optical fiber material ?
Last Answer : The refractive index of optical fiber material is 1.7 .
Description : The core of an optical fiber has a a. Lower refracted index than air b. Lower refractive index than the cladding c. Higher refractive index than the cladding d. Similar refractive index with the cladding
Last Answer : c. Higher refractive index than the cladding
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 : The refractive index number is ∙ A. a number which compares the transparency of a material with that of air ∙ B. a number of assigned by the manufacturer to the fiber in question ∙ C. a number which determines the core diameter ∙ D. a term describing core elasticity
Last Answer : A. a number which compares the transparency of a material with that of air
Description : Optical cable testers are used for ∙ a. Checking refractive index ∙ b. Light power out of a fiber ∙ c. Non-calibrated light into a fiber
Last Answer : b. Light power out of a fiber
Last Answer : ∙ b. Light power out of a fiber
Description : Which of the following is determined by an OTDR? ∙ a. Distance to trouble ∙ b. Length of fiber ∙ c. Refractive index ∙ d. All of these
Last Answer : d. All of these
Description : The core of an optical fiber has a ∙ a. Lower refracted index than air ∙ b. Lower refractive index than the cladding ∙ c. Higher refractive index than the cladding ∙ d. Similar refractive index with the cladding
Description : The claddingwhichsurroundsthe fiber core a. is used to reduce optical interference b. is used to protect the fiber c. acts to help guide the light in the core d. ensures that the refractive index remains constant
Last Answer : c. acts to help guide the light in the core
Description : What is the basic fiber cleaving technique for preparing optical fibers for coupling?
Last Answer : Score-and-break.
Description : In fiber-to-fiber connections, Fresnel reflection is one source of coupling losses. Light is reflected back into the source fiber and is lost. What causes Fresnel reflection?
Last Answer : A step change in refractive index that occurs at fiber joints, caused by fiber separation.
Description : How are source-to-fiber coupling and microbending and macrobending losses affected by changes in core diameter and D?
Last Answer : Coupling efficiency increases with both core diameter and D, while bending losses increase directly with core diameter and inversely with D.
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 : 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 : The dominant loss mechanisms in silica fiber are ∙ a. Absorption and radiation losses ∙ b. Absorption and Rayleigh scattering ∙ c. Coupling and radiation losses ∙ d. Radiation and modal dispersion
Last Answer : b. Absorption and Rayleigh scattering
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 : 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
Description : Is coupling loss from angular misalignment more critical in expanded beam or butt-jointed connectors?
Last Answer : Expanded beam connectors.
Description : What are the main causes of coupling loss?
Last Answer : Poor fiber end preparation and poor fiber alignment.
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 : 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 : 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 fiber property directly affects splice loss in fusion splicing?
Last Answer : The angles and quality of the two fiber-end faces.
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 : Microbend loss is caused by microscopic bends of the fiber axis. List three sources of microbend loss.
Last Answer : Uneven coating applications, improper cabling procedures, and external force.
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 : Which is not a possible cause of optical fiber loss? ∙ a. Impurities ∙ b. Glass attenuation ∙ c. Stepped index operation ∙ d. Microbending
Last Answer : ∙ c. Stepped index operation
Description : Which performance parameter is the minimum amount of optical power required to achieve a specific bit-error rate (BER) in digital systems or a given signal-to-noise ratio (SNR) in analog systems?
Last Answer : Receiver sensitivity.
Description : A large negative voltage is applied to the plate of a diode, and a largewhat tube parameter has been exceeded?
Last Answer : Peak Inverse Voltage (PIV).
Description : The value of the normalized frequency parameter (V) relates the core size with mode propagation. When single mode fibers propagate only the fundamental mode, what is the value of V?
Last Answer : V≤2.405.
Description : The parameter/s of the PQLI is/are a. Life Expectancy Index b. Standard of living index c. Infant mortality rate d. A and C
Last Answer : d. A and C
Description : For a cement plant the parameter, ―kWh/MT of clinker ―indicates a) Energy Index parameter b) Utility factor
Last Answer : Energy Index parameter
Description : For a cement plant the parameter, ―kWh/MT of clinker ―indicates a) Energy Index parameter b) Utility factor c) Production factor d) Load factor
Last Answer : Utility factor