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 : List the types of materials used in fabricating low-loss, long wavelength optical fibers.
Last Answer : Heavy-metal fluorides, chalcogenide glasses, and crystalline materials.
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 : 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 : How can loss be reduced during construction (or fabrication) of optical fibers?
Last Answer : By removing the impurities from optical 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 : Two methods describe how light propagates along an optical fiber. These methods define two theories of light propagation. What do we call these two theories?
Last Answer : The ray theory and the mode theory.
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 : 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 : 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 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 : LEDs operating at 850 nm provide sufficient optical power for short-distance, low-bandwidth multimode systems. List three conditions that prevent the use of LEDs in longer distance, higher bandwidth multimode systems.
Last Answer : Multimode fiber dispersion, the relatively high fiber attenuation, and the LED's relatively low optical output power.
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 : 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 : The amount of backscattered optical power at each point depends on what two properties?
Last Answer : Forward optical power and backscatter capture coefficient.
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 : 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 : Which type of optical source tends to operate at higher drive currents to produce light?
Last Answer : Laser.
Description : Which type of optical source usually lacks reflective facets and in some cases are designed to suppress reflections back into the active region?
Last Answer : LED.
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 : Which part of a fiber optic transmitter converts the processed electrical signal to an optical signal?
Last Answer : The optical source.
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 : List the three techniques used by manufacturers to buffer optical fibers.
Last Answer : Tight-buffered, loose-tube, and gel-filled loose-tube.
Description : List three benefits that properly cabled optical fibers provide.
Last Answer : a. Protect optical fibers from damage or breakage during installation and over the fiber's lifetime. b. Provide stable fiber transmission characteristics compared with uncabled fibers. c. Maintain the physical integrity of the optical fiber.
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 : 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 : 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 : 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 : 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 : 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 : 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 : Will an optical fiber's attenuation coefficient vary with changes in wavelength?
Last Answer : Yes.
Description : Optical fibers or cables should never be bent at a radius of curvature smaller than a certain value. Identify this radius of curvature
Last Answer : Minimum bend radius.
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 : 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 : List the three parts of an optical fiber.
Last Answer : Core, cladding, and coating or buffer.
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 : 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 : What are the two basic types of optical fibers?
Last Answer : Multimode and single mode fibers.
Description : What mechanisms in the fiber waveguides weaken and distort the optical signal?
Last Answer : Scattering, absorption, and dispersion.
Description : Define loss.
Last Answer : Loss is the decrease in the amount of light reaching the end of the fiber.
Description : For a single mode optical cable with 0.25 dB/km loss, determine the optical power 100 km from a 0.1-mW light source. ∙ A. -45 dBm ∙ B. -15 dBm ∙ C. -35 dBm
Last Answer : ∙ C. -35 dBm
Description : What are the basic requirements for any splice or terminal connection?
Last Answer : The connection must be both mechanically and electrically as strong as the conductor or device with which it is used
Description : Which fiber optic component (splice, connector, or coupler) makes a permanent connection in a distributed system?
Last Answer : Splice.
Description : Assurance engagement risk is the risk a. Of expressing an inappropriate conclusion when the subject matter information is not materially misstated. b. That the practitioner expresses an inappropriate ... , adverse publicity, or other events arising in connection with a subject matter reported on
Last Answer : That the practitioner expresses an inappropriate conclusion when the subject matter information is materially misstated.
Description : In case of end to end connection of two or more pipes in series, the __________ each pipe. (A) Same rate of flow passes through (B) Head loss is same through (C) Rate of flow in each pipe is proportional to the length of (D) Total flow rate is the sum of flow rate in
Last Answer : (A) Same rate of flow passes through