Introducing Fiber-Optic Networks Exam 2023 with Complete Solutions

Monitoring the status of optical nodes - ANSWER-By remote means is not critical for maintaining network stability and reliability???? Explaining Status Monitoring Remote monitoring of optical nodes is a critical function for network stability and reliability. All scalable nodes support status monitoringTechnology that allows the network operator to remotely monitor and pinpoint malfunctions anywhere in the network and analyze them on a computer. technology. A status monitoring node transponder monitors a number of critical functions, including power supply voltages, transmitter/receiver status, and temperature, and it usually monitors a tamper switch mechanism as well. A status monitoring transponder receives downstream information from a controller located in the headend. It also generates an upstream telemetry carrier that is combined into the reverse optical transmitter input. This telemetry carrier allows the transponder to continuously communicate node functions with the controller located at the headend. Any parameters exceeding a preset threshold will generate an alarm. Digital return path transmissions - ANSWER-Use dense wavelength division multiplexing (DWDM) digital return transmitters in hub-to-headend architectures. What is channel bonding? - ANSWER-A 3.0 revision to Data Over Cable Service Interface Specification (DOCSIS) that significantly increases upstream and downstream transport data rates. What is MPEG (Moving Picture Experts Group)? - ANSWER-A universally accepted standard for digital television, first released in 1992. Which of the following is true about optical nodes? - ANSWER-They contain four main sections: the optical receiver, the RF amplifier module, the reverse optical transmitter, and the DC power supply. What product based on the Data Over Cable Service Interface Specification (DOCSIS) defines the protocols for Internet protocol (IP) telephony over hybrid fiber/coax (HFC) networks? - ANSWER-PacketCable In a centralized server video-on-demand (VOD) architecture, - ANSWER-The number of servers needed for video content storage is smaller than in the distributed server architecture Which of the following statements about local ad insertion is true? - ANSWER-Local ad insertion is performed usually by a video server. In regard to providing high-speed data (HSD) service, - ANSWER-The cable modem termination system (CMTS) can provide a data transfer rate up to 38 Mbps, using 256-QAM in a single 6 MHz channel. Which of the following is true about the synchronous optical network (SONET) transmission standard? - ANSWER-SONET is the North American standard used for telephony applications. Why was the zero-dispersion point in single-mode fiber moved to 1,550 nm? - ANSWER-To take advantage of the low intrinsic absorption and lower attenuation at 1,550 nm in single-mode fiber. What type of single-mode fiber is intended for fiber-to-the-home (FTTH) installations? - ANSWER-The ITU-T G.657 bend-insensitive fiber (BIF). What are the primary causes of intrinsic loss in single-mode fiber? - ANSWER-Excessive bending and Rayleigh scattering.??? The phenomenon, total internal reflection, is what enables an optical fiber to guide light. What characteristic of optical fiber causes total internal reflection? - ANSWER-The difference in refractive indexes, between cladding and core, causes light to be reflected off the cladding and back into the core along the optical fiber. Where would you expect Fresnel reflections to occur in a fiber-optic network? - ANSWER-At connections and mechanical splices where the signal source is entering or exiting the cable. Chromatic dispersion is a combination of which two dispersions? - ANSWER-Material and waveguide dispersion. What is one advantage and one disadvantage of single-mode fiber with a large mode field diameter (MFD)? - ANSWER-The larger the MFD, the easier it is to splice and connectorize the fiber, although it becomes more sensitive to bending losses. What is the current standardized outside diameter (OD) of the cladding of single-mode fiber? - ANSWER-It is 125 μm, with an accuracy of ±1 μm. What do diameter differences between spliced fibers look like on an optical time domain reflectometer (OTDR)? - ANSWER-Gain in one direction and high loss in the opposite direction. Besides protection, what else must the coating on an optical fiber do? - ANSWER-Function over a wide temperature range; be compatible with cable gels; adhere to the glass cladding over the lifetime of the cable; and be mechanically strippable for splicing operations. How do technicians know the specific type of single-mode fiber used in a particular project? - ANSWER-They have read the project's specification records. Which type of fiber-optic cable provides the most stable transport characteristics and additional protection from stresses caused by macrobends and microbends? - ANSWER-Ribbon fiber requires different tools and equipment to perform splicing. What are the two critical elements that align the optical fibers in a connection? - ANSWER-The C-clip and adapter. In an optical network, what is reflectance? - ANSWER-Reflectance is the reflected light from a single Fresnel reflection event How should surface particulates usually be removed from optical connectors? - ANSWER-By using a compressed-air cleaner designed for optical connectors Since they provide the same functions, what is the primary difference between the fiber distribution hub (FDH) and fiber access terminal (FAT)?. - ANSWER-The FAT is typically easier to install and has lower fiber counts than the FDH. Which statement about pigtails used for optical fiber terminations is true? - ANSWER-Prior to splicing, pigtails should be labeled to correspond with the correct color code and patch panel designation. How are optical splitters used in the forward path? - ANSWER-In the forward path, optical splitters are used as passive branching devices that divide an optical signal across multiple output fibers. Which optical splitter package is similar in appearance and size to a standard fusion splice protector? - ANSWER-Fused biconical taper (FBT). In what applications is a splice closure used? - ANSWER-Splice closures are used to house electronics and spare cable, along with optical patch or splice panels.???? When preparing a fiber-optic cable for splicing, what is the purpose of removing approximately 2.5 cm (1 inch) of jacket and any armor that is present, from the end of the cable? - ANSWER-To access the cable's rip cord and to check the cutting depth of the knife or ringing tool. What does water do to the glass core of an optical fiber? - ANSWER-Water causes the glass core of the optical fiber to become opaque, which degrades the signal as it's transported through the fiber. When preparing a splice closure, what should be done with the fiberglass rod strength member that runs down the center of loose-tube fiber-optic cable? - ANSWER-Trim the strength member back for convenience, but leave it long enough to be tightly clamped to a strain-relief lug in the closure. What is the purpose of splice trays inside splice closures? - ANSWER-Splice trays are designed to provide protection for mechanical splices, fusion splice protectors, and optical splitters as well as provide storage for the required fiber slack. How should the buffer tubes be secured in the closure? - ANSWER-The buffer tubes should be secured with tie wraps to allow slight movement without pulling or stressing the optical fibers. How are optical splices secured in a splice tray? - ANSWER-Cable clips hold optical splices in place in a splice tray.???? What is the purpose of buffer tubes in fiber-optic cable? - ANSWER-Buffer tubes protect and separate the optical fiber in smaller bundles. When splicing fiber-optic cable, why is it a good safety practice to clean off fiber strippers and other hand tools after each use? - ANSWER-To prevent the accidental transfer of fiber debris or fiber chips onto clean hands. Where would you expect to install a mid-entry splice in a fiber-optic cable network? - ANSWER-A location where a select number of optical fibers need to be spliced, and the remaining buffer tubes and fibers remain untouched. Which type of fusion splicer is ideal for fiber-to-the-x (FTTx) splicing? - ANSWER-The fixed V-groove splicer. What are some prerequisites before performing a fusion splice of optical fibers? - ANSWER-A controlled environment such as a splicing van, trailer, or tent and a stable work surface that is large enough to accommodate the fusion splicer, tools, and the splice closure. When would a mid-entry splice in a fiber-optic network be used? - ANSWER-In a self-healing ring network that requires only two fibers to feed an optical fiber drop. What is required of mechanical splices used for acceptance testing? - ANSWER-A mechanical splice used for acceptance testing should be simple to use and reusable. Why are Velcro straps preferred over standard plastic tie wraps when bundling pigtails for storage in a splice panel? - ANSWER-Because Velcro straps are removable and can hold the pigtails together without placing undue strain on the optical fibers. When preparing fiber-optic cable for connection to a patch panel, how much buffer tube and fiber slack should be provided? - ANSWER-Leave enough slack in the buffer tubes