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 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 : 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 : 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 : ____ is a light that can be coherent ∙ a. Spontaneous emission ∙ b. Monochromatic and in-phase ∙ c. Narrow beam divergence ∙ d. Monochromatic
Last Answer : ∙ b. Monochromatic and in-phase
Description : The first laser emitted ∙ a. Pulses of 694 nm red light ∙ b. A continuous red beam ∙ c. Pulses of white light from a helical flash lamp ∙ d. Spontaneous emission
Last Answer : ∙ a. Pulses of 694 nm red light
Description : Laser light is ______ emission. ∙ a. Coherent ∙ b. Stimulated ∙ c. Spontaneous ∙ d. Coherent and stimulated
Last Answer : ∙ d. Coherent and stimulated
Description : The process of moving from one energy level to another is called ____________. ∙ A. Spontaneous emission ∙ B. Excited emission ∙ C. Absorption ∙ D. Spontaneous decay
Last Answer : C. Absorption
Description : The process of decaying from one energy level to another energy level is called __________. ∙ A. Spontaneous emission ∙ B. Excited emission ∙ C. Absorption ∙ D. Any of these
Last Answer : A. Spontaneous emission
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 : Is a non-coherent light source foe optical communications system. a. ILD b. LED c. APD d. PIN Diode
Last Answer : b. LED
Description : A non-coherent light source for optical communications system. A. PIN Diode B. ILD C. APD D. LED
Last Answer : D. LED
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
Description : Which laser emits light in the visible range 400 to 700 nm? ∙ a. Argon-ion ∙ b. Nitrogen ∙ c. Carbon-dioxide ∙ d. Neodymium-YAG
Last Answer : a. Argon-ion
Description : They wrote a paper describing how it was possible to use stimulated emission for amplifying light waves (laser) as well as microwaves (maser). ∙ A. Theodore Maiman ∙ B. KC Kao and GA Bockham ∙ C. Charles Townes and Arthur Schawlow ∙ D. Kapron, Keck and Maurer
Last Answer : C. Charles Townes and Arthur Schawlow
Description : Which of the following contributes to the broadening of laser emission bandwidth? ∙ a. Doppler shift of moving atoms and molecules ∙ b. Amplification within the laser medium ∙ c. Coherence of the laser light ∙ d. Optical pumping of the laser transition
Last Answer : Doppler shift of moving atoms and molecules
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 : Any energy above the ground state is called ___________. ∙ A. normal state ∙ B. above-ground state ∙ C. excited state ∙ D. spontaneous state
Last Answer : D. spontaneous state
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 : 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 : 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 : Which light emitter is preferred for high-speed data in a fiber-optic system? ∙ A. incandescent ∙ B. LED ∙ C. neon ∙ D. laser
Last Answer : D. laser
Description : Which light emitter is preferred for high speed data in a fiber-optic system ∙ a. Incandescent ∙ b. LED ∙ c. Neon ∙ d. Laser
Last Answer : ∙ d. Laser
Description : Optical power is sometimes called __________. ∙ A. Radiant emission ∙ B. Radiant power ∙ C. Radiant flux ∙ D. Radiant optics
Last Answer : C. Radiant flux
Description : The emission in which the atom emits a photon of energy hf = E2 – E1 , in any arbitrary direction is a) Spontaneous emission b) stimulated emission c) induced emission d) both a & c
Last Answer : d) both a & c
Description : APD stands for: a. Avalanche Photodiode b. Advanced Photodiode c. Avalanche Photo Detector d. Advanced Photo Detector
Last Answer : a. Avalanche Photodiode
Description : What is the spectral width of a standard LED? ∙ A. 20 to 40 nm ∙ B. 30 to 50 nm ∙ C. 10 to 30 nm ∙ D. 40 to 60 nm
Last Answer : 30 to 50 nm
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
Description : An ohmmeter used to test for front-to-back resistance of a PN junction diode should produce roughly what ratio? A. 100:01:00 B. 500:01:00 C. 1000:01:00 D. 5000:01:00
Last Answer : Answer: A
Description : Write some applications of PN junction diode
Last Answer : 1. Rectifier circuit ii. clipping and clamping iii voltage multiplier iv AM detection v. Feedback diodes vi Freewheeling diode
Description : What is the purpose of a PN junction diode?
Last Answer : To convert alternating current into direct current
Description : State any Four applications of PN junction diode.
Last Answer : 1. Rectifiers in power supplies, 2. Detectors in RF, 3 .Clippers, 4. In clamping networks used as DC Restorers, 5. As switches in digital logic circuits.
Description : Describe the working of PN junction diode with neat sketch under forward biased condition.
Last Answer : If the p-region (anode) is connected to the positive terminal of the external DC source and nside (cathode) is connected to the negative terminal of the DC source then the biasing ... The large number of majority carriers crossing the junction constitutes a current called as the forward current.
Description : Plot and explain I -V characteristics of a PN junction diode.
Last Answer : V-I characteristics of PN junction diode: Explanation: Forward Bias: If the external voltage applied on the silicon diode is less than 0.7 volts, the silicon diode ... reverse breakdown voltage. * Diode breakdown occurs by two mechanisms: Avalanche breakdown and Zener breakdown.
Description : LASER stands for: a. Light Amplification by Simulated Emission of Radiation b. Light Amplification by Stimulated Emission of Radiation c. Light Amplification by Simulated Emitted Rays d. Light Amplification by Stimulated Emitted Rays
Last Answer : b. Light Amplification by Stimulated Emission of Radiation
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 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 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 : 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