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 : APD stands for: a. Avalanche Photodiode b. Advanced Photodiode c. Avalanche Photo Detector d. Advanced Photo Detector
Last Answer : a. Avalanche Photodiode
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 : A pn-junction diode emits light by spontaneous emission ∙ A. LED ∙ B. APD ∙ C. PIN
Last Answer : A. LED
Description : . Is a non-coherent light source foe optical communications system. ∙ a. ILD ∙ b. LED ∙ c. APD ∙ d. PIN Diode
Last Answer : ∙ b. LED
Description : Which optical detector is used when high sensitivity and bandwidth are required? ∙ a. PMT ∙ b. APD ∙ c. PIN ∙ d. Phototransistor
Last Answer : a. PMT
Description : One of the following is not a solid-state optical detector ∙ a. APD ∙ b. PIN ∙ c. PMT ∙ d. Phototransistors
Last Answer : . PMT
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 : Which of the following is used as an optical transmitter on the Fiber Optical Communications? ∙ a. APD ∙ b. LSA diode ∙ c. PIN diode ∙ d. LED
Last Answer : d. LED
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 : 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 : 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 : 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 : 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 ____________________ diode is the usual light detector for single-mode
Last Answer : PIN
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 : 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 : When connector losses, splice losses and coupler losses are added, what is the limiting factor? ∙ A. source power ∙ B. fiber attenuation ∙ C. connector and splice loss ∙ D. detector sensitivity
Last Answer : D. detector sensitivity
Description : The three major groups of the optical system are ∙ A. the components, the data rate and the response time ∙ B. the source, the link and the receiver ∙ C. the transmitter, the cable and the receiver ∙ D. the source, the link and the detector
Last Answer : B. the source, the link and the receiver
Description : The _____ of a detector is the fraction of incident photons that produce a photoelectron or electron-hole pair ∙ a. Responsitivity ∙ b. Photon efficiency ∙ c. Aperture ∙ d. Quantum efficiency
Last Answer : d. Quantum efficiency
Description : The most common device used as a light detector in fiber optic communications system. A. LED B. Darlington phototransistor C. APDs D. PIN diode
Last Answer : C. APDs
Description : Which of the following is used as an optical receiver in fiber optics communications ∙ a. APD ∙ b. Tunnel diode ∙ c. Laser diode ∙ d. LED
Last Answer : a. APD
Description : A sensor which changes light intensity into electric voltage. (a) LDR (b) thermistor (c) photodiode (d) photovoltaic
Last Answer : (a) LDR
Description : For a light detector, responsivity is measured in: a. amps per watt b. µW per amp c. mA per joule d. µsec per µW
Last Answer : a. amps per watt
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 of the following is not a common application of fiber-optic cable? ∙ A. computer networks ∙ B. long-distance telephone system ∙ C. closed-circuit TV ∙ D. consumer TV
Last Answer : ∙ D. consumer TV
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 : ∙ a. Single-mode step-index
Description : Which of the following is not a common application of fiber-optic cable? ∙ a. Computer networks ∙ b. Long-distance telephone systems ∙ c. Closed circuit TV ∙ d. Consumer TV
Last Answer : d. Consumer TV
Description : Avalanche photodiode receivers can detect bits of transmitted data by receiving a. 100 photons b. 200 photons c. 2000 photons d. 300 photons
Last Answer : 200 photons
Description : Avalanche photodiode receivers candetect hits of transmitted databy receiving A. 100 photons B. 200 photons C. 300 photons D. 400 photons E. None of the above
Description : Draw the construction of Avalanche photodiode. State its working principle.
Last Answer : Avalanche photodiode are used to obtain the large gain, i.e. large output because Conventional photodiodes and PIN photodiodes obtain the limited gain. CONSTRUCTION: APD's are usually variation ... in avalanche with the number of carriers growing exponentially as the process continues.
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 : 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 : 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 : 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 : 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