TOP 250+ Fiber Optics Interview Questions and Answers 13 September 2022 - Fiber Optics Interview Questions | Wisdom Jobs India (2022)

  • Question 1. Do Signals Really Travel Faster In Fiber Optics?

    Answer :

    You know that "sending communications at the speed of light" means the speed of light in glass (about 2/3 C), but you might be surprised to know that signals in UTP (unshielded twisted pair) cables like Cat 5e travel at about the same speed (2/3 C). Coax, meanwhile, has a faster NVP (nominal velocity of propagation), about 0.9C, due to it's design. Fibers "speed" is not referring to the speed of the signal in the fiber, but the bandwidth potential of the fiber.

  • Question 2. Can You Give Me A Definition Of Structured Cabling?

    Answer :

    "Structured Cabling" refers to a standardized cabling architecture, specified by EIA/TIA 568 in the US and ISO 11801 internationally. It uses twisted pair and fiber optic cables to create a standardized cabling system designed for telephones and LANs built by many manufacturers. The nomenclature here is even less precise. Vendors also refer to this as "structured cabling", data-voice cabling, low-voltage cabling and limited-energy cabling.

  • Networking Interview Questions
  • Question 3. What Are Some Of The Uses Of Fiber Optic Cabling In The Business World?

    Answer :

    The biggest use is telephony, followed by CATV, then LAN backbones, connecting hubs. Next is connecting remote video cameras for security systems. The building management and security systems are switching to fiber in many buildings due to distance and EMI requirements. Fiber is not often used to the desk because it is perceived to be too expensive, but it allows a system without wiring closets, making the cost less in most instances. Gigabit Ethernet will drive even more fiber into networks, since UTP applications will be too difficult to install.

  • Question 4. Will "intelligent Buildings" Use Fiber Optics Or Copper Wiring To Carry Voice/data/video Throughout The Structure?

    Answer :

    Both. Fiber will be used when the distances are longer than 90 meters or data rates are higher (e.g. Gigabit Ethernet). Most backbones will be fiber. Desktop connections to telecom closets will be copper for the near future, until network managers find out what a telecom closet really costs! Phones will continue to use copper until we all go to voice over IP. Video (CCTV) uses fiber for distances over about 150-250 meters.

  • Networking Tutorial
  • Question 5. I Need To Be Able To Measure The "true" Or "useful" Power Of A Vcsel Laser Diode. To Do This, I Believe I Need To Measure The Peak-to-peak Power (the Extinction Ratio?).

    (Video) Information & Communication Technology - Revision Series Paper 1 Oct 2021 Dr Trupti

    Answer :

    All FO power meters measure average power. This is simply peak power diluted by duty cycle. If you know the duty cycle of the signal and the average power, you can calculate peak power as (Avg pwr/duty cycle). If you are measuring a signal with a clock of 50% duty cycle (1-0-1-0, etc), the meter will read half the peak power. Most high speed networks are sending random data, so the duty cycle can probably be assumed to be 50%. Many systems have a test mode that transmits 50% duty cycle just for optical testing.

  • Telecommunication Project Management Interview Questions
  • Question 6. How Do You Classify Fiber Optic Cable?

    Answer :

    By NEC - UL - flame retardancy

    By cable types (tight buffer/distribution/breakout/loose tube)

    By fiber types (multimode/singlemode/hybrid)

    Whether it has fiber and wire (composite cable)

  • Question 7. What Type Of Fiber Is Required To Run At Gigabit Speed?

    Answer :

    Depends on how far you want to go. Plain old FDDI fiber (160 MHz-km bandwidth @ 850 nm and 500 MHz-km @ 1300 nm ) will go ~240 m with a 850 VCSEL or 500 m with a 1300 laser. Practically every fiber manufacturer has 50/125 laser-optimized premium fiber (OM2/OM3/OM4) that will go a lot further -as far as 2 km - and while it's more expensive, we recommend it for any backbone applications.

  • Telecom Billing Tutorial Network Administrator Interview Questions
  • Question 8. What Is Modal Bandwidth, And How Does It Effect What Distances Gigabit Ethernet Can Travel Over Fiber?

    Answer :

    Modal bandwidth is caused by the fact that light in multimode fiber travels in rays or "modes" that take different times to get to through the fiber, causing dispersion. The longer the fiber, the greater the effect. This is a major factor in the distance limitation of GBE and the incentive for fiber manufacturers to develop better multimode fiber. While the worst case distance for 62.5/125 FDDI-spec fiber using a 850 nm VCSEL source is only 220 m, laser-optimized 50/125 fiber capable of 1 km is now available.

  • Question 9. What Is The Difference In Connectorization In Tight Buffered And Loose Tube Type Of Cables?

    Answer :

    A tight buffer cable can be terminated directly. THe 900 micron coating on the fiber is rugged enough to allow the connection to be connected directly and if there is a 3 mm jacket, it is crimped to the connector for strength.

    A loose tube cable has 250 micron buffer on the fiber in it and is too fragile to attach a connector directly. It has be be used with a breakout kit that sleeves the fiber in a protective tube before termination.

  • Telephone Etiquette Interview Questions
  • Question 10. Can I Splice 62.5/125 Fiber To 50/125 Fiber? If So What Type Of Nominal Loss Would I Be Looking At At For My Loss Budget?

    Answer :

    If you splice it, you will get directional losses. Transmitting from 50 to 62.5 fiber, you'll get virtually no losses but from 62.5 to 50, you will get a minimum of 1.6-1.9 dB loss due to the size and NA mismatch. (50 micron fiber has a lower numerical aperture (NA) than 62.5) for a table of interconnection losses with different size fibers.

  • Question 11. Does This Still Hold True With Six Fiber Or 12 Fiber Premise Style Cable?

    Answer :

    Absolutely. Remove the jacket, cut off the fibers and central strength member and tie a swivel onto the kevlar. You'll need about 6 inches of kevlar, tie with a double knot on the swivel then tape the kevlar back along the cable, esp. covering the end of the jacket, to prevent the kevlar from pulling loose or the cable snagging while pulling.

  • Ethernet Interview Questions
  • Question 12. Is There Any Independent Testing Procedures On "rodent Proof" Optical Cables And What Sort Of Qualification/s Being Used To Justify?

    Answer :

    There is a test referenced in GR-20 issue 2. I have heard that there are facilities which still perform the test, but I am not familiar with any of them. I know of no-one who is trying to justify the test.

  • Networking Interview Questions
  • Question 13. What Measurements Are Manufacturers Using When They Claimed That Their Products Are Of "rodent Resistance", "rodent Proof" And "rodent Protection".

    Answer :

    The test referenced above did not use any of these terms, but just gave a damage rating. There is anecdotal information that some cable / duct types have less rodent damage in the field than other cable / duct types.

  • Question 14. How Are These Three Terms Differentiate In Terms Of Classification With Respect To The Rodent Issue"?

    Answer :

    There is no organization, of which I am aware, which gives any formal definition to the terms. Rodent resistance" and "rodent protection" are currently used by some organizations, for cable designs which they feel have experienced less damage in the field. "Rodent proof" , to the best of my knowledge, has only been used by a company which makes ductwork .

  • Question 15. Can You Give Me A Definition Of Fiber Optics?

    Answer :

    What we call "fiber optics" is communications by modulated light guided through a transparent optical fiber. As a relatively young technology, the nomenclature can be quite varied among users. In the UK, it's fiber optics, sometimes its fiber optics or fiber optics (as one word). Within the business, we generally say "fiber" when we refer to the optical fiber itself, although some use it to mean a cable of optical fiber. Lennie Lightwave has a fiber optic glossary on the web.

  • Telecom Billing Interview Questions
  • Question 16. What Do I Need For Connecting Optic Fibre Cable To A Cat 5 Cable?

    Answer :

    You need a device called a "media converter" available from a number of companies for $100-200.

  • Question 17. Will A Single Mode Connector Work On Multi-mode Cable?

    Answer :

    The answer is maybe you can use SM connectors on MM but NOT the reverse. SM connectors are made to tighter tolerances - as is SM fiber - so the ferrule hole may be too small for some MM fibers. MM connectors have bigger holes for the fiber and will have high loss (>1dB) with SM. Also MM connectors may not be PC (physical contact) polish - terrible for return loss. MM fiber may not fit the smaller hole in SM connectors.

  • Question 18. If You Have A 50 Micron Fiber Backbone, Can You Use 62.5 Fiber Jumpers On Each End?

    Answer :

    NO! On the receiver end it is OK, but on the transmitter end, the larger core of 62.5 into smaller 50 micron fiber will have losses of 2-4 dB.

  • Telecommunication Project Management Interview Questions
  • Question 19. Why Do Some Power Meters Have Calibration At 1300 Nm While Others Are 1310 Nm?

    Answer :

    Convention. The "official" laser center wavelength is 1310 nm, but vary between 1290 and 1330 nm. LEDs are broad spectral output devices that have outputs over a broad range of wavelengths, roughly centered around 1300 nm. We prefer to just say 1300 nm, and so does NIST, who calibrate at this wavelength with a 1300 nm YAG laser.

  • Question 20. Where Do I Find The Best Information On Fiber Optics For Lighting?

    Answer :

    We're not into fiber optic lighting but we have a tutorial on lighting on our website.

  • FAQs

    What are the 3 fiber optics parts? ›

    The three basic elements of a fiber optic cable are the core, the cladding and the coating.

    What is optical fiber and its types? ›

    Types of optical fiber

    There are two primary types of fiber, each of which has a different application. These are multimode (MM) fiber, which has a large core and allows for multiple paths through the fiber, and single-mode (SM) fiber, which has only one path, through a much smaller core.

    What are the basics of fiber optics? ›

    Fiber Basics

    Optical fiber is a highly-transparent strand of glass that transmits light signals with low attenuation (loss of signal power) over long distances, providing nearly limitless bandwidth. This technology enables telecommunications service providers to send voice, data, and video at ever increasing rates.

    What is 2 core fiber cable? ›

    2 Core Fiber Optic Cable

    The optical fiber unit is positioned in the centre. Two parallel Fiber Reinforced Plastics (FRP) are placed at the two sides.

    What is the size of fiber optic cable? ›

    Let's talk about fiber optic types and core sizes. There are three common core sizes: 9/125, 50/125, and 62.5/125. Each of those numbers stands for a measurement, and that measurement is in microns.

    What type of fiber optic cable is used for internet? ›

    There are two types of fiber optic cabling, single mode and multimode. Single mode, which can transmit a single wavelength of light long distances, is used primarily for WAN connections. Multimode can transmit multiple signals at one tim, but is more limited in length and typically used in LANs.

    Why is fiber optic faster than cable? ›

    The throughput of the data is determined by the frequency range that a cable will carry — the higher the frequency range, the greater the bandwidth and the more data that can be put through per unit time. And this is the key difference — fibre optic cables have much higher bandwidths than copper cables.

    What is fiber internet speed? ›

    Fiber-optic internet, commonly called fiber internet or simply “fiber,” is a broadband connection that can reach speeds of up to 940 Megabits per second (Mbps), with low lag time. The technology uses fiber-optic cable, which amazingly can send data as fast as about 70% the speed of light.

    What are the types of fibers? ›

    There are 2 different types of fiber -- soluble and insoluble.

    What is V number in optical fiber? ›

    The V number determines the fraction of the optical power in a certain mode which is confined to the fiber core. For single-mode fibers, that fraction is low for low V values (e.g. below 1), and reaches ≈ 90% near the single-mode cut-off at V ≈ 2.405.

    How many types of fiber optic cable are there? ›

    There are two types of fibre optic cables – multimode and single-mode. Multimode optical fibre or OFC is capable of carrying multiple light rays (modes) at the same time as it has varying optical properties at the core.

    Are there different types of fiber cable? ›

    There are three types of fiber optic cable commonly used: single mode, multimode and plastic optical fiber (POF).

    What are modes of light? ›

    The mode theory is used to describe the properties of light that ray theory is unable to explain. The mode theory uses electromagnetic wave behavior to describe the propagation of light along a fiber. A set of guided electromagnetic waves is called the modes of the fiber.

    How many fibers are in a cable? ›

    Modern fiber cables can contain up to a thousand fiber strands in a single cable although the highest strand-count single-mode fiber cable commonly manufactured is the 864-count, consisting of 36 ribbons each containing 24 strands of fiber.

    How do you calculate fiber optic cable? ›

    A value of “002” means 2 fiber strands, “048” means 48 fiber strands. Valid fiber counts are: 002, 004, 006, 008, 012, 024, 036, 048, 72, 96 144, 288. “01” means 1 fiber per sub unit (tube).

    What is critical angle in optical fiber? ›

    critical angle, in optics, the greatest angle at which a ray of light, travelling in one transparent medium, can strike the boundary between that medium and a second of lower refractive index without being totally reflected within the first medium.

    What is the largest fiber optic cable? ›

    Fibre-optic Link Around the Globe (FLAG) is a 28,000-kilometre-long (17,398 mi; 15,119 nmi) fibre optic mostly-submarine communications cable that connects the United Kingdom, Japan, India, and many places in between. The cable is operated by Global Cloud Xchange, a subsidiary of RCOM.

    What is 24 core fiber cable? ›

    24 Core Fibre Cable – Internal/External TightBuffered OM4 50/125µm. Molex OM4 fibre is a graded-index multimode fibre with extended reach, optimised for 10Gb/s transmission speeds. The fibre is designed for use at 850nm, but can also be used at 1300nm. Applications include backbone cabling, LAN premise cabling.

    How many fibers are in a tube? ›

    Since most loose tube cables have 12 fibers per tube, colors are specified for fibers 1-12, then tubes are color coded in the same manner, up to 144 fiber cables.

    What color is fiber optic cable? ›

    Cable Jacket Colors
    Fiber TypeColor Code
    Multimode (62.5/125) (OM1)OrangeOM1, 62.5/125
    Multimode (100/140)Orange100/140
    Single-mode (OS1, OS1a, OS2)YellowOS1, OS1a, OS2, SM/NZDS, SM
    Polarization Maintaining Single-modeBlueUndefined (2)
    4 more rows

    What is an OTDR machine? ›

    Network Cabling Contractors and Installers. An Optical Time Domain Reflectometer (OTDR) is a device that tests the integrity of a fiber cable and is used for the building, certifying, maintaining, and troubleshooting fiber optic systems.

    What type of cable is used for internet? ›

    An Ethernet cable is used for faster speeds, like Cat 5e and Cat 6e (or higher). Ethernet cables connect your modem, router, computer, and other wired Internet-capable devices to carry broadband signals.

    Which is faster cable or fiber? ›

    Fiber optic internet speed is about 20 times faster than regular cable internet and 80 times faster than DSL. With prices only $10 to $20 more monthly, fiber is the right choice for most internet users.

    How many types of losses are there in optical Fibre? ›

    There are two basic loss mechanisms in optical fibres. These are absorption and scattering: 1. Absorption loss.

    What is the difference between cable and fiber optic? ›

    Fiber-optic internet services is faster compared to the cable network with a speed of not less than 250-1,000 Mbps in both directions. Many people can access the fiber network at the same time without affecting the overall performance.

    What is a good fiber optic speed? ›

    Most fiber Internet providers offer speeds up to 100 Gbps, or the equivalent of 100,000 Mbps. At 100 Gbps, a download of a 2GB file would take approximately 1 second, while the same file would take roughly 7 minutes over a 40 Mbps connection.

    What is the highest Internet speed? ›

    Google Fiber is the fastest internet provider in the United States, delivering the fastest average speeds to its customers on the most consistent basis. With maximum advertised speeds up to 2,000 Mbps and 12-month average download speeds of 167.1 Mbps, the fiber provider earns an integrated speed score (ISS) of 185.2.

    Is 5G faster than fiber? ›

    Fiber internet is faster and more reliable than the 5G network, becoming the preferred choice among tech experts. With speeds up to 100 times faster than traditional broadband, a fiber connection can easily handle all of your online needs.

    Which type of fiber is best? ›

    A review of 44 studies on fiber treatments found that only viscous fibers reduced food intake and caused weight loss ( 19 ). Viscous fibers include glucomannan, beta-glucans, pectins, guar gum and psyllium. Good whole-food sources include legumes, asparagus, Brussels sprouts, oats and flax seeds.

    What are the two types of natural fibre? ›

    Plant fibres include seed hairs, such as cotton; stem (or bast) fibres, such as flax and hemp;leaf fibres, such as sisal; and husk fibres, such as coconut. Animal fibres include wool, hair and secretions, such as silk.

    What are the main sources of fibre? ›

    Great sources are whole grains, whole fruits and vegetables, legumes, and nuts.

    What is AV number? ›

    And, when a call arrives on our phone with the caller ID starting with a V + a long string of digits, we wonder what it might be. What in the world is a caller ID V02873828347838? A V in your caller ID refers to a number from a telemarketing company. It is likely this call is Spam.

    What is the value V? ›

    V-Value (V) or normalized frequency is the fundamental relationship between numerical aperture, cut-off wavelength and core radius in step-index fibers. By definition V=2.405 at the cut-off wavelength of every single-mode fiber waveguide.

    What is bending loss? ›

    Bend losses mean that optical fibers exhibit additional propagation losses by coupling light from core modes (guided modes) to cladding modes when they are bent. Typically, these losses rise very quickly once a certain critical bend radius is reached.

    Who invented Fibre optic? ›

    Charles Kuen Kao is known as the “father of fiber optic communications” for his discovery in the 1960s of certain physical properties of glass, which laid the groundwork for high-speed data communication in the Information Age.

    What are two applications for optical fibers? ›

    Applications of Optical Fiber
    • Medical. Used as light guides, imaging tools and also as lasers for surgeries.
    • Defense/Government. ...
    • Data Storage. ...
    • Telecommunications. ...
    • Networking. ...
    • Industrial/Commercial. ...
    • Broadcast/CATV.

    What are optical Fibres two uses? ›

    They are arranged In a bundles called optical cables and used to transmit light signals over long distances. Main applications of Optical fibers are communication system, medicine, sensors, military, and electronics.

    What is difference between single and multimode fiber? ›

    single mode fiber is designed to propagate a single light mode whereas multimode supports multiple simultaneous light modes. This difference impacts bandwidth, signal transmission distance and signal stability which we'll explore later.

    What is a fiber optic port called? ›

    Most fiber optic connectors are plugs or so-called male connectors with a protruding ferrule that holds the fibers and aligns fibers for mating. They use a mating adapter to mate the two connector ferrules that fits the securing mechanism of the connectors (bayonet, screw-on or snap-in.)

    What is OS1 and OS2 fiber? ›

    OS1 fiber optic cable is designed for premises where the maximum distance is 2,000 metres with transmission speeds of 1 to 10 gigabit Ethernet. OS2 fiber optic cable is designed for larger transmission distances in the range of 5,000 to 10,000 metres with similar transmission speed of 1 to 10 gigabit Ethernet.

    Which light is used in optical Fibre? ›

    Laser light is used for optical fiber communications for the simple reason that it is a single wavelength light source. Sunlight or the light emitted by a light bulb is a mixture of many different wavelengths of light.

    What is mode of fiber? ›

    Fiber types

    There are basically three types of optical fiber: single mode, multimode graded index, and multimode step-index. They are characterized by the way light travels down the fiber and depend on both the wavelength of the light and the mechanical geometry of the fiber.

    Which ray is used in optical fiber? ›

    For fiber optics with glass fibers, we use light in the infrared region which has wavelengths longer than visible light, typically around 850, 1300 and 1550 nm.

    What are the 3 main layers of Fibre optic cabling and list their function? ›

    Typically, a fiber optic cable contains three basic components: the core, which carries the light signals; the cladding, which surrounds the core with a lower refractive index and contains the light; and the coating, which protects the fragile core and cladding within it.

    What are the major components of an optical system? ›

    An optical system consists of a succession of elements, which may include lenses, mirrors, light sources, detectors, projection screens, reflecting prisms, dispersing devices, filters and thin films, and fibre-optics bundles.

    What are the components of optical fibre communication system? ›

    The basic components are light signal transmitter, the optical fiber, and the photo detecting receiver. The additional elements such as fiber and cable splicers and connectors, regenerators, beam splitters, and optical amplifiers are employed to improve the performance of the communication system.

    What is structure of optical fiber? ›

    Optical fiber is composed of three elements – the core, the cladding and the coating. These elements carry data by way of infrared light, thus propagating signal through the fiber. The core is at the center of the optical fiber and provides a pathway for light to travel.

    What are the 4 types of optical fiber cable construction? ›

    A fiber optic cable consists of five main components: core, cladding, coating, strengthening fibers, and cable jacket.

    What type of cable is used for fiber Internet? ›

    The technology uses fiber-optic cable, which amazingly can send data as fast as about 70% the speed of light. In addition, fiber-optic cables are not as susceptible to severe weather conditions as other types of traditional cables, which helps minimize outages. It also resists electrical interference effectively.

    What are the four parts of a fiber optic cable? ›

    The different components that make up a fiber cable are the core, cladding, Kevlar®, ferrule, and connector. After assembly, the fiber core is polished and then it is ready to transmit data. The core is a continuous strand of super thin glass that is roughly the same size as a human hair.

    What are two types of optical detector? ›

    That is the where the optical detectors come in .
    • Photoelectric effect.
    • Semiconductor Photodiode.
    • Summary.
    24 Jul 2018

    Which method is used in optical fiber? ›

    An optical fiber cable consists of a core, cladding, and a buffer (a protective outer coating), in which the cladding guides the light along the core by using the method of total internal reflection.

    What is minimum number of layers in an optical fiber? ›

    The basic optical fiber consists of two concentric layers—the inner core and the outer cladding, which has a refractive index lower than the core.

    Which are the five main parts of optical fibre? ›

    The cladding of the Optical fibre is made up of Glass / Plastic. Buffer: The Buffer is the moisture substance that is coated over the surface of the cladding. They are mainly used to provide flexibility to the optical fibre's core and cladding. Jacket: The jacket is the outer surface of the optical fibre.

    What is the maximum bandwidth of fiber optic cable? ›

    The current maximum bandwidth for fiber-optic cabling is 100Gbps. But research is being done to try and increase both speed and bandwidth even further. In 2021, Japanese scientists set a new world record by developing a four-core optical fiber achieving record-breaking speeds of 319 terabits.

    Why is fibre optic used? ›

    Fiber optic cables are commonly used because of their advantages over copper cables. Some of those benefits include higher bandwidth and transmit speeds. Fiber optics is used for long-distance and high-performance data networking.

    What is the color code for fiber optic cable? ›

    Cable Jacket Colors
    Fiber TypeColor Code
    Multimode (62.5/125) (OM1)OrangeOM1, 62.5/125
    Multimode (100/140)Orange100/140
    Single-mode (OS1, OS1a, OS2)YellowOS1, OS1a, OS2, SM/NZDS, SM
    Polarization Maintaining Single-modeBlueUndefined (2)
    4 more rows

    Who invented fibre optic? ›

    Charles Kuen Kao is known as the “father of fiber optic communications” for his discovery in the 1960s of certain physical properties of glass, which laid the groundwork for high-speed data communication in the Information Age.

    What are modes of light? ›

    The mode theory is used to describe the properties of light that ray theory is unable to explain. The mode theory uses electromagnetic wave behavior to describe the propagation of light along a fiber. A set of guided electromagnetic waves is called the modes of the fiber.

    You might also like

    Latest Posts

    Article information

    Author: Pres. Lawanda Wiegand

    Last Updated: 06/04/2022

    Views: 6226

    Rating: 4 / 5 (71 voted)

    Reviews: 94% of readers found this page helpful

    Author information

    Name: Pres. Lawanda Wiegand

    Birthday: 1993-01-10

    Address: Suite 391 6963 Ullrich Shore, Bellefort, WI 01350-7893

    Phone: +6806610432415

    Job: Dynamic Manufacturing Assistant

    Hobby: amateur radio, Taekwondo, Wood carving, Parkour, Skateboarding, Running, Rafting

    Introduction: My name is Pres. Lawanda Wiegand, I am a inquisitive, helpful, glamorous, cheerful, open, clever, innocent person who loves writing and wants to share my knowledge and understanding with you.