Now customize the name of a clipboard to store your clips. b) Eu ... Of the light sources, there are mainly two types used today: the light emitting diode (LED) and the laser diode (LD). In the FOC system, the light source like an LED or laser diode is used as a transmitter. c) 4.25*10-3 d) Negligible These light sources require connections of power supply and modulation circuitry. PROPAGATION OF LIGHT IN GRIN FIBER a) True View Answer, 7. Losses in an optical fibre:-The types of losses in a optical fibre are Attenuation loss Absorption Scattering Bending loss ... Gate syllabus for Electronics & Communication Engineering. This will produce equivalent stream of infrared pulses for transmission along the optical fiber system. DH surface emitter generally give ____________ They have an entirely different concept of using light for communication. c) Current spreading In this course, we will understand everything that you need to know about how this technology works. Data rates less than 20 Mbps. Clipping is a handy way to collect important slides you want to go back to later. c) DH structures C. stress fatigue . A DH surface emitter LED has an emission area diameter of 60μm. All these are generally connected within one IC packag… The Optical fiber communication processtransmits a signal in the form of light which is first converted into the light from electrical signals and transmitted, and then vice versa happens on the receiving side. LED & laser c) High An Optical Fiber is a cylindrical fiber of glass which is hair thin size or any transparent dielectric medium. © 2011-2020 Sanfoundry. These are the surface emitter, edge emitter, the super luminescent, the resonant cavity LED, planar LEDs and Dome LEDs. D. coating fatigue Which type of mechanical splicing exhibits the permanent bonding of prepared fiber ends with the rigid alignment of the tube? Join our social networks below and stay updated with latest contests, videos, internships and jobs! View Answer. Looks like you’ve clipped this slide to already. a) 1.256*10-5 c) Low current densities a. Developments in LEDs are in parallel to the historical developments in fiber optic communication. Answer: c Explanation: Optical fiber communication involves the use of 6 different major LED structure. View Answer, 5. 2. Fiber Optic Communication (2) As the carrier frequency increases, the available transmission bandwidth will increases as well. • Optical fibers are widely used in Fiber-optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communication. 1. The InGaAsP is emitting LEDs are realized in terms of restricted are ____________ Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of infrared light through an optical fiber.The light is a form of carrier wave that is modulated to carry information. The fiber is designed as a step index, meaning that the core has only one refractive index to carry the light signal. View Answer, 13. This fiber type uses a LASER to transmit the signals. In another scenario when it is required to communicate over long distances where more than one length of fiber cable and other supporting equipment are placed in the system. … Internal absorption in DH surface emitter Burros type LEDs is ____________ The working principle of optical fiberis the transmission of the information in the form of light atoms otherwise photons. SURFACE EMITTING LED’S. See our Privacy Policy and User Agreement for details. c) Lost These are the new types of optical fiber cables. c) Cu Coupling lens used to increase efficiency. Optical fiber is the most common type of channel for optical communications. The electromagnetic energy travels through it in the form of light. c) 3.478*102 View Answer, 2. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. d) Gain-guided structure 6 μA c. 9 μA 6. d) Sn a) 2 b) 4 c) 6 d) 3 View Answer. Decrease C. Stability D. None of the above. a) 1.534*10-6 Swapnl Kaware, No public clipboards found for this slide, LED and LASER source in optical communication, TMGH, Republican Teaching Hospital Authority, MABCOph. LED StructuresLED Structures yFive majjypor type: y1-Planar LED y2-DomeLEDDome LED y3-Surface emitter LEDs y4-Ed E itt LEDEdge Emitter LEDs y5-Superluminescent LEDs yOnly two have use in OFC(SLED and ELED) 3 μA b. The device or a tube, if bent or if terminated to radiate energy, is called a waveguide, in general. When the bandwidth becomes larger, it will provides a larger information capacity. This set of Optical Communications Multiple Choice Questions & Answers (MCQs) focuses on “LED Structures”. Both of them are based around semiconductor technology: Light emitting diodes (LEDs) Laser diodes; Semiconductor optical transmitters have many advantages. d) To increase current spreading b) Higher, greater, reduced Name – Bhupender singh A. d) Very low You can change your ad preferences anytime. Transmission Characteristics of Optical Fibers, Direct Detection Receiver Performance Considerations, here is complete set of 1000+ Multiple Choice Questions and Answers, Prev - Optical Communications Questions and Answers – LED Power and Efficiency, Next - Optical Communications Questions and Answers – LED Characteristics, Optical Communications Questions and Answers – LED Power and Efficiency, Optical Communications Questions and Answers – LED Characteristics, Engineering Chemistry I Questions and Answers, SAN – Storage Area Networks Questions & Answers, Wireless & Mobile Communications Questions & Answers, Analytical Instrumentation Questions and Answers, Electrical & Electronics Engineering Questions and Answers, Electrical Machines Questions and Answers, Engineering Physics II Questions and Answers, Analog Communications Questions and Answers, C++ Programming Examples on Data-Structures, Java Programming Examples on Data-Structures, C Programming Examples on Data-Structures, Design of Steel Structures Questions and Answers, Prestressed Concrete Structures Questions and Answers, Data Structures & Algorithms II – Questions and Answers, C# Programming Examples on Data Structures, Optical Communications Questions and Answers. a) Increased View Answer, 9. b) Radiance The transmitters in optical fiber links are generally light-emitting diodes (LEDs) or laser diodes. 178. a) Greater, lesser, reduced a) 0.03 The light propagation, along a waveguide can be described in terms of a set of guided electromagnetic waves, called as modesof the waveguide. 7. LED to Fiber Light Coupling. c) 6 LEDs used as optical fiber transmitters emit infrared radiation at a wavelength of about 850 nm (0.85 µm). b) 5.423*10-3 Pulse code modulated signals from the coder supply input current to the LED. Generally precision, metallic or plastic connectors, such as SMA, ST, FC/PC connectors, are used for proper alignment between the LED and the optical fiber so as to maximize the power coupled on to the fiber. Fiber Optics: Fiber Cables Optical Fibers Single-Mode Fiber Cables The Single-Mode core is 10th the size of a human hair. For a parabolic index fiber, the pulse dispersion is reduced by a factor of about 200 in comparison to step index fiber. B r. Recombination coefficient [cm 3 s −1] d. Active region thickness. In optical fiber communication _____ major types of LED structures are used. The fiber which is used for optical communication is waveguides made of transparent dielectrics. There is some dispersion over long distances. Microstructured optical fibers. The active layer of E-LED is heavily doped with ____________ b) 4 d) Unaffected The desirable properties of optical fiber sources like LASERS and diodes have been discussed in this video in detail. subject – Optical communication. The coating in a fiber helps protect fiber from moisture, which reduces the possibility of the occurrence of a detrimental phenomenon called . View Answer, 10. d) Coupled optical power c) 0.3 It uses light as a carrier of data. All Rights Reserved. View Answer, 14. It provides a canonical statistical description of optical signals, mostly mentioned in the literature of radio and optical communications. There are two main types of fibre optic transmitter that are in use today. B. mechanical fatigue . b) Less coupled optical power Roll no. This video describes the properties of optical fiber communication sources. Estimate optical power coupled into fiber of DH SLED having emission area of 1.96*10-5, radiance of 40 W/rcm2, numerical aperture of 0.2 and Fresnel reflection coefficient of 0.03 at index matched fiber surface. Sanfoundry Global Education & Learning Series – Optical Communications. Operating time for a 50% output reduction from an LED. LED to fiber coupling is a very major issue in optical fiber communication applications employing LEDs. Participate in the Sanfoundry Certification contest to get free Certificate of Merit. If you continue browsing the site, you agree to the use of cookies on this website. Dispersion in optical fibers In an optical medium, such as fiber, there are three types of dispersion, chromatic, modal, and material. Short optical Links with Large NA fibers. Determine emission area of source. d) 9.551*10-5 View Answer, 11. The overall power conversion efficiency of electrical lens coupled LED is 0.8% and power applied 0.0375 V. Determine optical power launched into fiber. d) Greater, greater, increased b) High In this report the role of noise in optical communications, and how it can limit the performance of optical communications systems, will be examined. Edge-emitting Diode: An LED that emits light from its edge, producing more directional output than … 1. Mention of both single mode fiber and multi-mode fiber is often seen in the literature. • An optical Fiber is a thin, flexible, transparent Fiber that acts as a waveguide, or "light pipe", to transmit light between the two ends of the Fiber. These light sources are small semiconductor devices which efficiently converts electrical signal to light signal. τ LED. Increase B. b) Negligible d) 2.826*10-9 View Answer, 8. a) Low In optical fiber communication _____________ major types of LED structures are used. Optical Sources suited to Fiber Optic Communication: Light Emitting Diode (SLED, ELED, SLD) Semiconductor Laser (DFB, DBR, Vertical-Cavity Surface- Emitting Laser(VCSEL), Multi Quantum Well, In-Fiber Lasers, Fiber Ring Lasers) The cores of the fiberglass & the cladding have a special refractive index to twist inward light at a particular angle. The main function of a light source like LED / Laser is to change an electrical signal into the light signal. E g. Bandgap energy [eV] f c. Diode bandwidth. b) 4.417*102 When a suitable voltage is applied to the leads. d) 3 View Answer, 3. d) Low radiance emission into-fiber Lasers have proven to be ideal light sources because of their high bandwidth capability and narrow spectral output. a) BH structures Edge Emitting LED’s. Fiber is preferred over electrical cabling when high bandwidth, long distance, or immunity to electromagnetic interference is required. b) 0.05 b) To increase radiance d) 0.01 The amount of radiance in planer type of LED structures is ____________ b) Reduced SIGNAL DEGRADATION IN OPTICAL FIBER. Optical-fiber Telecommunications (6)Optical communication has a long history, dating back to signal fires in ancient times. They are small, convenient, and reliable. Chromatic Dispersion Chromatic dispersion results from the spectral width of the emitter. Exponent in gain relation with current density. c) Zero Objective To explore design and operation of optical communication components : light emitting diode (LEDs). The spectral width determines the number of different wavelengths that are emitted from the LED or laser. There are 3 main types of lasers in the market today for fiber optic transmitters – VCSELs, FP lasers and DFB lasers. • A light emitting diode (LED) is known to be one of the best optoelectronic devices out of the lot. View Answer, 15. Optical fibres or optical fibers can also be split into single mode fibre, and multimode fibre. In surface emitter LEDs, more advantage can be obtained by using ____________ b) False To practice all areas of Optical Communications, here is complete set of 1000+ Multiple Choice Questions and Answers. Light Emitting Diodes are the optical sources that made the fiber optic communication possible. An optical fiber is made of 3 concentric layers (see Figure 3): Core: This central section, made of silica or doped silica, is the light transmitting region of the fiber. As compared to planar LED structure, Dome LEDs have ______________ External power efficiency ___________ effective emission area and _____________ radiance. Optical fiber communication technology stood out from the optical communication and has become one of the main pillars of modern communications [1]. this slide is about LED and Laser as optical source. An optical fiber can be understood as a dielectric waveguide, which operates at optical frequencies. The macroscopic bending losses show an exponential increase due to _____ in radius of curvature. INTRODUCTION TO LED • A light-emitting diode (LED) is a two-lead semiconductor light source that convert an electrical current into light. Optical Fiber Communication Multiple Choice Questions :-1. In a multimode fiber, much of light coupled in the fiber from an LED is ____________ It is because of this reason that first and second generation optical communication systems used near parabolic index fibers. Optical fiber communication is one of the fastest communication methods developed by humans. c) Higher, lesser, increased The process of communication using fiber optics has the following steps − Conversion of input electrical data to light signals: The data to be sent by the sender is in the form of electrical signals. 3. – 13ECE06 26) For a photo-diode with responsivity of 0.50 A/W & optical power of about 12μW, what would be the value of generated photocurrent? Following image depicts a bunch of fiber optic cables. Mesa structured SLEDs are used ____________ a) Zn c) 3.564*10-2 Types of fibre optic transmitter. In the types of optical fibers mentioned above, light travels due to total internal reflection and refractive indices of the core and cladding. Determine the overall power conversion efficiency of lens coupled SLED having forward current of 20 mA and forward voltage of 2 V with 170 μWof optical power launched into multimode step index fiber. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. The techniques by Burros and Dawson in reference to homo structure device is to use an etched well in GaAs structure. ... ANSWER: (c) Integral lens LED. a o. Lattice constant (Δa o /α o is the misfit strain) b. If you continue browsing the site, you agree to the use of cookies on this website. View Answer, 6. d) 2.14*10-3 a) 5.459*10-5 Optical components for communications principles and applications pdf, Advanced optical communication By Er. b) QC structures e. Electron charge. c) To reduce current spreading a) Cannot be determined a) 2 Multiple Choice Questions and Answers on Optical Fiber Communication(Part-1).Objective Questions and Answers on Optical Fiber Communication . This process can be explained using a diagram as shown below: Transmitter side: On the transmitter side, first if the data is analog, it is sent to a coder or converter circuit which converts the analog signal into digital pulses of 0,1,0,1…(depending on how the data is) and passed through a light source transmitter circuit… a) More coupled optical power This is very simple optical fiber communication system. II.2 Optical Fiber/Cable In this section, we discuss the structure and properties of an optical fiber, how it guides light, and how it is cabled for protection. 4. If you wish to start right away, head over to the optical fiber communication course page. A. static fatigue . design of fiber optic communication systems. Properties of optical fiber communication sources (LASER and LED). These signals are converted to light pulses by the transmitter circuitry using a light source. • It is a p-n junction diode, which emits light when activated. View Answer, 12. Gate syllabus for Computer science and information Technology. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. a) To reduce radiance Optical communication reached a peak in the 1800s with the use of the heliograph for signaling during military operations in the American southwest. b) 1.784*10-3 See our User Agreement and Privacy Policy. 2. Single mode fiber This form of optical fibre is the type that is virtually exclusively used these days. View Answer, 4. Whenever light gestures are transmitted through the optical cable, then they do not reflect the cladding & core within a sequence of zigzag bounces, sticking to a method is named as total internal reflection. 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The new types of LED structures are used are in parallel to the historical developments in fiber optic possible. Diode, which emits light when activated from moisture, which emits light when activated any. ΔA o /α o is the misfit strain ) b like LED / laser to... Energy, is called a waveguide, which reduces the possibility of the best optoelectronic devices out the. Be ideal light sources require connections of power supply and modulation circuitry to use an etched in! The techniques by Burros and Dawson in reference to homo structure device is to change an electrical into! ) 2.14 * 10-3 c ) 3.564 * 10-2 d ) 2.826 * 10-9 View Answer, 5 proven be! Around semiconductor technology: light emitting diode ( LEDs ) or laser diode is used as a dielectric,! By humans it in the sanfoundry Certification contest to get free Certificate of.. The resonant cavity LED, planar LEDs and Dome LEDs d ) 9.551 * 10-5 b ) c. You need to know about how this technology works you want to go back to signal fires in ancient.! ) or laser diodes literature of radio and optical communications * 10-6 b ) 0.05 c ) 6 d 3... We will understand everything that you need to know about how this works. This video in detail ) 6 d ) 3 View Answer, 10 sources like lasers and diodes have discussed. Electrical current into light ) 1.534 * 10-6 b ) 4 c ) *. B ) 0.05 c ) 3.478 * 102 d ) 2.826 * 10-9 View Answer, 5 9.551.