Description : A popular light wavelength fiber-optic cable is ∙ A. 0.7 micrometer ∙ B. 1.3 micrometer ∙ C. 1.5 micrometer ∙ D. 1.8 micrometer
Last Answer : B. 1.3 micrometer
Description : Optical fibers for telecommunications are typically about _____ mils thick and consists of a glass core, a glass cladding of lower index of refraction, and a protective coating ∙ a. 5 ∙ b. 6 ∙ c. 7 ∙ d. 8
Last Answer : ∙ a. 5
Description : Single-mode step-index cable has a core diameter in the range of ∙ A. 100 to 1000 micrometer ∙ B. 50 to 100 micrometer ∙ C. 2 to 15 micrometer ∙ D. 5 to 20 micrometer
Last Answer : . 2 to 15 micrometer
Description : Light rays that are emitted simultaneously from an LED and propagated down an optical fiber do not arrive at the far end of the fiber at the same time results to ∙ A. intramodal dispersion ∙ B. pulse length dispersion ∙ C. modal dispersion ∙ D. wavelength dispersion
Last Answer : D. wavelength dispersion
Description : Infrared light has a wavelength that is ∙ A. less than 400 nm ∙ B. more than 700 nm ∙ C. less than 700 nm ∙ D. a little over 400 nm
Last Answer : B. more than 700 nm
Description : The higher the index number ∙ A. the higher the speed of light ∙ B. the lower the speed of light ∙ C. has no effect on the speed of light ∙ D. the shorter the wavelength propagation
Last Answer : B. the lower the speed of light
Description : Which of the following terms best describes the reason that light is refracted at different angles? ∙ A. Photon energy changes with wavelength ∙ B. Light is refracted as a function of surface smoothness ∙ ... determined partly by a and b ∙ D. The angle is determined by the index of the materials
Last Answer : ∙ D. The angle is determined by the index of the materials
Description : ange of wavelength of visible light ∙ A. 670 nm to 10^3 nm ∙ B. 440 nm to 540 nm ∙ C. 110 nm to 240 nm ∙ D. 390 nm to 770 nm
Last Answer : D. 390 nm to 770 nm
Description : What is the typical wavelength of light emitted from epitaxially grown LEDs? ∙ a. 840 nm ∙ b. 490 nm ∙ c. 480 nm ∙ d. 940 nm
Last Answer : ∙ d. 940 nm
Description : What parameter of light detector determines the range or system length that can be achieved for a given wavelength? ∙ a. Transit time ∙ b. Spectral response ∙ c. Dark current ∙ d. Responsitivity
Last Answer : ∙ b. Spectral response
Description : A popular light wavelength in fiber-optic cable is ∙ a. 0.7 um ∙ b. 1.3 um ∙ c. 1.5 um ∙ d. 1.8 um
Last Answer : b. 1.3 um
Description : The wavelength of visible light extends from ∙ a. 0.8 to 1.0 nm ∙ b. 400 to 750 nm ∙ c. 200 to 660 nm ∙ d. 700 to 1200 nm
Last Answer : b. 400 to 750 nm
Description : The laser frequency when the light has the wavelength 800 nm is ∙ a. 375 x 1012 Hz ∙ b. 475 x 1015 Hz ∙ c. 375 x 109 Hz ∙ d. 375 x 1018 Hz
Last Answer : d. 375 x 1018 Hz
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 : The wavelength of light has no role in ∙ a. Diffraction ∙ b. Interference ∙ c. Polarization ∙ d. Reflection
Last Answer : c. Polarization
Description : When a beam of light enters one medium from another, which quantity will not change? ∙ a. Direction ∙ b. Speed ∙ c. Frequency ∙ d. Wavelength
Last Answer : c. Frequency
Description : Is the different angle of entry of light into an optical fiber when the diameter of the core is many times the wavelength of the light transmitted. ∙ a. Acceptance angle ∙ b. Modes ∙ c. Sensors ∙ d. Aperture
Last Answer : b. Modes
Description : Which color has the shortest wavelength of light? ∙ a. Red ∙ b. Yellow ∙ c. Blue ∙ d. Green
Last Answer : c. Blue
Description : The wavelength of a visible extends from ∙ A. 0.8 to 1.6 um ∙ B. 400 to 750 nm ∙ C. 200 to 660 nm ∙ D. 700 to 1200 nm
Last Answer : B. 400 to 750 nm
Description : The range of wavelength values that a given photodiode will respond. ∙ A. spectral response ∙ B. permeance ∙ C. dark current ∙ D. reluctance
Last Answer : A. spectral response
Description : How many modes possible with a multimode step-index with a core diameter of 50 um, a core refractive index of 1.6, a cladding refractive index of 1.584, and a wavelength of 1300 nm. ∙ A. 456 ∙ B. 213 ∙ C. 145 ∙ D. 372
Last Answer : D. 372
Description : The bandwidth of a fiber is limited by ∙ a. Mode ∙ b. Wavelength ∙ c. Dispersion ∙ d. Frequency
Last Answer : c. Dispersion
Description : Modal dispersion is caused by the ∙ a. Dependence of wavelength on index of refraction ∙ b. Dependence of propagation constant on index of refraction ∙ c. Dependence of the propagation constant on the wavelength ∙ d. Dependence of the propagation constant on the mode number
Last Answer : d. Dependence of the propagation constant on the mode number
Description : Material dispersion is caused by the ∙ a. Wavelength dependence of the index of refraction ∙ b. Wavelength independence of the index of refraction ∙ c. Dependence of the propagation constant on the mode number ∙ d. Independence of the propagation constant on the mode number
Last Answer : d. Independence of the propagation constant on the mode number
Description : Light intensity is generally described in terms of __________ and measured in _________. ∙ A. Luminous flux density; Lumens per unit area ∙ B. Luminous flux intensity; Lumens per unit area ∙ C. Luminous flux density; Lumens per unit volume ∙ D. Luminous flux intensity; Lumens per unit volume
Last Answer : Luminous flux density; Lumens per unit area
Description : What is the unit of responsitivity? ∙ a. Ampere/volt ∙ b. Ampere/watt ∙ c. Watt/ampere ∙ d. Volts/ampere
Last Answer : ∙ a. Ampere/volt
Description : Refraction is the ∙ A. bending of light ∙ B. reflection of light waves ∙ C. distortion of light waves ∙ D. diffusion of light waves
Last Answer : A. bending of light
Description : The main benefit of light wave communications over microwaves or any other communications media are ∙ A. lower cost ∙ B. better security ∙ C. wider bandwidth ∙ D. freedom from interface
Last Answer : C. wider bandwidth
Description : EMD is best described by which statement? ∙ A. 70 percent of the core diameter and 70% of the fiber NA should be filled with light. ∙ B. 70 percent of the fiber diameter and 70% of the ... be measured at the output. ∙ D. 70 percent of the unwanted wavelengths should be attenuated by the fiber.
Last Answer : 70 percent of the core diameter and 70% of the fiber NA should be filled with light.
Description : The speed of light in plastic compared to the speed of light in air is ∙ A. less ∙ B. more ∙ C. the same ∙ D. zero
Last Answer : A. less
Description : The upper pulse rate and information-carrying capacity of a cable is limited by ∙ A. pulse shortening ∙ B. attenuation ∙ C. light leakage ∙ D. modal dispersion
Last Answer : D. modal dispersion
Description : Total internal reflection takes place if the light ray strikes the interface at an angle with what relationship to the critical angle? ∙ A. less than ∙ B. greater than ∙ C. equal to ∙ D. zero
Last Answer : ∙ B. greater than
Description : The minimum optical power a light detector can receive and still produce a usable electrical output signal. ∙ A. light responsivity ∙ B. light sensitivity ∙ C. light collectivity ∙ D. illumination
Last Answer : B. light sensitivity
Description : The term responsivity as it applies to a light detector is best described as ∙ A. the time required for the signal to go from 10 to 90 percent of maximum amplitude ∙ B. the ratio of the diode ... . the ratio of the input power to output power ∙ D. the ratio of output current to input current
Last Answer : the ratio of the diode output current to the input optical power
Description : The time it takes a light induced carrier travel across the depletion region of the semiconductor. ∙ A. dispersion ∙ B. response time ∙ C. irradiance ∙ D. transit time
Last Answer : D. transit time
Description : The leakage current that flows through a photodiode with no light input ∙ A. dark voltage ∙ B. dark impedance ∙ C. dark power ∙ D. dark current
Last Answer : D. dark current
Description : A pn-junction diode emits light by spontaneous emission ∙ A. LED ∙ B. APD ∙ C. PIN
Last Answer : A. LED
Description : How can modal dispersion reduced entirely? ∙ A. Use a graded index fiber ∙ B. Use a single-mode fiber ∙ C. Use a monochromatic light source ∙ D. Use a very sensitive light detector
Last Answer : Use a single-mode fiber
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 : As light is coupled in a multiport deflective device, the power is reduced by ∙ A. 1.5 dB ∙ B. 0.1 dB ∙ C. 0.5 dB ∙ D. 0.001 dB
Last Answer : C. 0.5 dB
Description : Chromatic dispersion can be eliminated by __________. ∙ A. using a monochromatic light source ∙ B. using a very small numerical aperture fiber ∙ C. using a graded-index fiber ∙ D. using a very sensitive photo detector
Last Answer : A. using a monochromatic light source
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 : It is caused by hydroxide ions in the material ∙ A. visible light absorption ∙ B. infrared absorption ∙ C. ultraviolet absorption ∙ D. ion resonance absorption
Last Answer : D. ion resonance absorption
Description : t is a result of photons of light that are absorbed by the atoms of the glass core molecule. ∙ A. ion resonance absorption ∙ B. infrared absorption ∙ C. ultraviolet absorption ∙ D. visible light absorption
Last Answer : B. infrared absorption
Description : It is caused by valence electrons in the silica material from which the fiber are manufactured. ∙ A. ion resonance absorption ∙ B. infrared absorption ∙ C. ultraviolet absorption ∙ D. visible light absorption
Last Answer : ultraviolet absorption
Description : It is analogous to power dissipation to copper cables, impurities in the fiber absorb the light and covert it to heat. ∙ A. power loss ∙ B. absorption loss ∙ C. resistive loss ∙ D. heat loss
Last Answer : B. absorption loss
Description : Which of the following is not a factor in cable light loss? ∙ A. reflection ∙ B. absorption ∙ C. scattering ∙ D. dispersion
Last Answer : A. reflection
Description : Results in reduction in the power of light wave as it travels down the cable. ∙ A. power loss ∙ B. absorption loss ∙ C. resistive loss ∙ D. heat loss
Last Answer : A. power loss
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