Hw10-1_1 - disadvantages of using DCM in the transmission....

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1 IEG 4030 (09-10) Assignment 1 Select three problems from each part. Part A. Fiber (Due: Feb 24, 2010, Wed) 1. Consider a piece of step-index optical fiber with a refractive index at the fiber core of 1.47 and a fractional refractive index change for the core and the cladding of 0.02. (a) What should be the maximum fiber core diameter if this fiber is designed to be single-mode for wavelength starting from 1,000nm? (b) Estimate the number of modes if the fiber used for 850nm laser. 2. A 40-km optical fiber transmission link is built using standard single mode fiber (e.g Corning SMF-28e) at a transmission wavelength of 1550nm. In order to compensate the pulse broadening due to fiber chromatic dispersion, we employ dispersion compensation module (DCM), with the specification attached in a separate file, DCM.pdf. Assume the dispersion coefficient of standard single-mode fiber is +17ps/km/nm @ 1550nm. (a) Determine which DCM module should be used by calculating the required value dispersion in “ps/nm” for the DCM. (b) Discuss the
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Unformatted text preview: disadvantages of using DCM in the transmission. 3. To measure the attenuation coefficient of fiber, a cut-back method in the following apparatus can be employed. A sample of fiber is first installed. The output power is measured to be P 1 (dBm). Then the fiber is cut short on the output part by, say, 50 cm. The output power, P 2 , is measured. (a) Find the fiber attenuation (in dB/km) expressed in P 1 and P 2 . (b) Discuss what may affect the accuracy of this measurement technique for fiber attenuation. 4. Simple answer questions (a) State the pros and cons of using a fiber with large numerical aperture (N.A.). (b) Discuss the effects of reducing fiber core diameter for optical transmission on the power coupling between the laser and fiber, the dispersion, fiber bending loss, dispersion, and others. Laser Fiber under test Lens for power coupling Large Area Optical Power Meter...
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This note was uploaded on 05/18/2010 for the course INFORMATIO IEG 4030 taught by Professor Liank.che during the Spring '10 term at CUHK.

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