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Slide 1: 642-311 Cisco Optical SONET Exam(SONET) Exam 642-311 Demo Edition © 2005- 2006 Test Killer, LTD All Rights Reserved 1 http://www.testkiller.com http://www.troytec.com Slide 2: 642-311 QUESTION: 1 What are three factors that limit the maximum distance of an amplified optical signal without regeneration? (Choose three.) A. fiber dispersion B. signal attenuation C. transmitter power D. amplifier bandwidth E. receiver dispersion tolerance Answer: ABE QUESTION: 2 In order to avoid misconnections due to a failed node in a Bidirectional Line Switched Ring (BLSR), Alarm Indication Signals (AISs) are sent on every channel normally terminating in that node. What is the name of this process? A. trunking B. squelching C. nodal bypass D. bridge and roll E. node failure insertion Answer: B QUESTION: 3 Why are the 1300 nm and 1550 nm regions of the fiber spectrum primarily used for optical communications? A. They are both regions of lowest loss. B. They are both regions of low reflections. C. They are both regions of low index of refraction. D. They are both regions of low chromatic dispersion. E. They are both regions of low Polarization Mode Dispersion (PMD). Answer: A QUESTION: 4 Which device creates an OEO conversion? A. amplifier B. attenuator C. regenerator D. light emitter E. optical switch F. optical receiver G. fiber-optic cable Answer: C http://www.testkiller.com http://www.troytec.com 2 Slide 3: 642-311 QUESTION: 5 What three in combination are factors that can cause four-wave mixing in fiber-optic cables? (Choose three.) A. low optical power B. high optical power C. few optical channels D. many optical channels E. low chromatic dispersion F. high chromatic dispersion G. too much power differential in the optical channels Answer: BDE QUESTION: 6 What is an advantage of an externally modulated laser over a directly modulated laser? A. lower cost B. higher chirp C. easier to manufacture D. higher dispersion tolerance E. higher optical signal-to-noise ratio Answer: D QUESTION: 7 Which three technologies are used to reduce chromatic dispersion accumulation in fiber-optic transmission systems? (Choose three.) A. PIN photodiodes B. zero-chirped lasers C. Erbium-doped fiber amplifiers D. dispersion compensating fiber E. dispersion compensating Bragg grating Answer: BDE QUESTION: 8 What is the difference between the transmitted power and the sensitivity of the receiver? A. OSNR B. dispersion C. attenuation D. power budget E. amplifier spacing F. four wave mixing Answer: D 3 http://www.testkiller.com http://www.troytec.com Slide 4: 642-311 QUESTION: 9 If the power is 0 dBm, what is the power in mW? A. 0 mW B. 1 mW C. 10 mW D. 1.5 mW Answer: B QUESTION: 10 What is the phenomenon called where different wavelengths of light travel at different speeds? A. OSNR B. dispersion C. light skew D. attenuation Answer: B QUESTION: 11 Given the formula: (Fiber Attenuation * Km) + (Splice Attenuation * # of Splices) + (Connector Attenuation * # of Connectors) + (Optical Fiber or OADM) + Buffer(Fiber aging)) With regard to SONET/SDH optical calculations, what will the given formula provide? A. fiber loss B. OSNR level C. post amplification D. index of reflection E. index of refraction F. power post amplification budget Answer: A QUESTION: 12 If the dispersion of a given fiber is 17ps/nmkm at 1550 nm and zero at 1310 nm, then what is the accumulated dispersion of an ITU wavelength after it travels 200 km? A. 0 ps/nm B. 340 ps/nm C. 200 ps/nm D. 3400 ps/nm E. More information is needed. Answer: D 4 http://www.testkiller.com http://www.troytec.com Slide 5: 642-311 QUESTION: 13 The dispersion of a non-zero dispersion shifted fiber is 6 ps/nmkm at 1550 nm and 10 ps/nmkm at 1610 nm. What is the minimum dispersion compensation required if an L-Band DWDM signal travels through 200 km of fiber and has a dispersion tolerance of 1800 ps/nm? A. none B. -600 ps/nm C. -200 ps/nm D. +200 ps/nm E. +600 ps/nm Answer: C QUESTION: 14 How is a Thin Film filter fabricated? A. The glass core is doped with an Erbium in periodic segments of the fiber. B. Layers of high index “H” and low index “L” material are deposited on a glass substrate. C. Thin layers of silica glass are placed onto wafers to produce a prism-like effect. D. Fiber is etched with an ultraviolet laser that is precisely spaced for specific wavelength filtering. Answer: B 15. Click the Exhibit button. Answer: Pending. Please put your suggestions to gary@troytecsupport.com. QUESTION: 15 Which type of multiplexer is shown in the exhibit? A. Thin Film filter B. Fiber Bragg Grating C. Arrayed Wave Guide D. Erbium fiber amplifier Answer: C QUESTION:16 For lasers with tightly controlled wavelengths, approximately how far apart are the centers of adjacent wavelengths when 100 GHz spacing is used in a DWDM system? 5 http://www.testkiller.com http://www.troytec.com Slide 6: 642-311 A. 0.4 nanometers B. 0.6 nanometers C. 0.8 nanometers D. 1.2 nanometers E. 1.6 nanometers Answer: C QUESTION:17 Click the Exhibit button. When designing a DWDM system with multiple amplified spans, a pre-amp is needed at Site B to _____. (Choose three.) A. offset the OADM loss at site B B. overcome the high multiplexer loss at site A C. amplify signal levels after the high loss through Fiber Span 1 D. adjust add channels at site B to be at the same level as the passthrough channels E. ensure that the per channel power is higher than the minimum needed for the post-amp at Site B Answer: ACE QUESTION:18 In the OSNR model for EDFA amplifiers, SNROUT = 1/(1/SNRIN + FhvB/PIN), what does SNRIN represent? A. the signal to noise of the current optical amplifier B. the signal to noise of the previous amplifier or source C. the signal to noise introduced by the optical multiplexer D. the accumulated noise to signal ratio of the optical channel Answer: B QUESTION:19 Click the Exhibit button. http://www.testkiller.com http://www.troytec.com 6 Slide 7: 642-311 What is the maximum allowable loss budget between the ONS 15216 Mux (left side) composite output and the ONS 15216 Demux (right side) composite input, with the optical values given in the exhibit? (Assume the worst case loss of 4.5 dB for 15216 200 GHz Mux/Demux and ignore power penalties or extra margin.) A. 15 dB B. 17 dB C. 21 dB D. 26 dB E. 27 dB Answer: B QUESTION: 20 Click the Exhibit button. 7 http://www.testkiller.com http://www.troytec.com Slide 8*: 642-311 The exhibit shows a 15454/15216 DWDM system and alarm indications. What are two possible sources of trouble shown in the system? (Choose two.) A. fiber failure between Sites A and D B. EDFA failure at Site A (clockwise direction) C. EDFA failure at Site C (clockwise direction) D. 15216 multiplexer at Site A (counter-clockwise direction) E. OADM pass-through (West "OUT") failure at site D (clockwise) F. wavelengths 1 and 3 transmitter failures at Site A (clockwise direction) Answer: AB 8 http://www.testkiller.com http://www.troytec.com