Description : Dark current in light detectors is caused by ∙ a. Thermally generated carriers in the diode ∙ b. The absence of light input ∙ c. Small leakage current ∙ d. Its imperfection
Last Answer : a. Thermally generated carriers in the diode
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 : Which of the following is the fastest light sensor? ∙ A. PIN photodiode ∙ B. Photovoltaic diode ∙ C. Photodiode ∙ D. Avalanche photodiode
Last Answer : Avalanche photodiode
Last Answer : D. Avalanche photodiode
Description : Which of the following is the fastest light sensor ∙ a. PIN photodiode ∙ b. Photovoltaic diode ∙ c. Phototransistor ∙ d. Avalanche photodiode
Last Answer : ∙ d. Avalanche photodiode
Description : Which of the following is NOT a common light detector ∙ a. PIN photodiode ∙ b. Photovoltaic diode ∙ c. Photodiode ∙ d. Avalanche photodiode
Last Answer : ∙ b. Photovoltaic diode
Description : In a PIN diode, leakage current in the absence of light is called: a. baseline current b. zero-point current c. dark current d. E-H current
Last Answer : c. dark current
Description : It is described as the flow of light energy past a given point in a specified time ∙ A. Optical radiation ∙ B. Optical impedance ∙ C. Optical illusion ∙ D. Optical power
Last Answer : D. Optical power
Description : In radiometric terms, it measures the rate at which electromagnetic waves transfer light energy ∙ A. Optical radiation ∙ B. Optical impedance ∙ C. Optical illusion ∙ D. Optical power
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 : 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 : 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 : 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 measure of conversion efficiency of a photodetector. ∙ A. Efficiency ∙ B. Responsivity ∙ C. Dark current ∙ D. Spectral response
Last Answer : B. Responsivity
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 : APD stands for: a. Avalanche Photodiode b. Advanced Photodiode c. Avalanche Photo Detector d. Advanced Photo Detector
Last Answer : a. Avalanche Photodiode
Description : They experimented with light transmission cables through bundle of fibers and lead to the development of flexible fiberscope. ∙ A. Townes, Schawlow and Kao ∙ B. Maiman, Kao and Bockham ∙ C. Maurer, Kapron and Keck ∙ D. Van Heel, Hopkins and Kapany
Last Answer : D. Van Heel, Hopkins and Kapany
Description : Coherence of laser light is important for _________ ∙ a. Light propagation ∙ b. Getting laser light to pass through air ∙ c. Drilling holes ∙ d. Holography
Last Answer : d. Holography
Description : What is used to block light from a laser and let other light through ∙ a. Neutral density ∙ b. Color ∙ c. Interference ∙ d. Spatial
Last Answer : ∙ c. Interference
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 : 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 : 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 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 : 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 : 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 : The loss in signal power as light travels down a fiber is called ∙ a. Dispersion ∙ b. Scattering ∙ c. Absorption ∙ d. Attenuation
Last Answer : ∙ d. Attenuation
Description : Cable attenuation is usually expressed in terms of ∙ A. loss per foot ∙ B. dB/km ∙ C. intensity per mile ∙ D. voltage drop per inch
Last Answer : . dB/km
Description : Cable attenuation is usually expressed in terms of ∙ a. Loss per foot ∙ b. dB/km ∙ c. intensity per mile ∙ d. voltage drop per inch
Last Answer : ∙ b. dB/km
Description : Photodiodes used as fiber optic directors are ∙ a. Unbiased to generate a voltage same as a solar cell ∙ b. Forward bias ∙ c. Reversed bias ∙ d. Thermoelectrically cooled
Last Answer : ∙ c. Reversed bias
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 : The wavelength of light has no role in ∙ a. Diffraction ∙ b. Interference ∙ c. Polarization ∙ d. Reflection
Last Answer : c. Polarization
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 : 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 : 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 : 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 : 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 : 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 : 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 : 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 : 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 : 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 : 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 : 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