Influence of the Number of Degrees of Freedom on the Capacity of Incoherent Optical Fiber Communication Systems

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" Influence of the Number of Degrees of Freedom on the Capacity of Incoherent Optical Fiber Communication Systems "

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	150213
Doc. No	:	ET22005
Main Entry	:	Seemant Teotia
Title Proper	:	Influence of the Number of Degrees of Freedom on the Capacity of Incoherent Optical Fiber Communication Systems
Note	:	This document is digital این مدرک بصورت الکترونیکی می باشد
Abstract	:	The purpose of this dissertation is to find the channel capacity in optical fibercommunication systems when incoherent detection is used with single (polarizationfiltering) and two-polarizations (no polarization filtering).Optical fiber systems employ photodetectors that convert optical intensity to electricalcurrent. Bandpass vector fields may be represented by four orthogonal basebandcomponents corresponding to two quadrature phases and two orthogonal polarizations.Intensity is proportional to the sum of the squares of these four components. In the caseof a coherent receiver, a strong optical local oscillator (in phase and with samepolarization as the signal) is added to the signal prior to the photodetector. This results inthe removal of the quadrature phase and polarization components, and reduces to the onedegree of freedom (DOF) case of signal plus local oscillator shot noise for which theShannon channel capacity formula applies. Electrical noise following the photodetectormay also be neglected if there is an optical amplifier before the photodetector in thereceiver. The amplifier introduces amplified spontaneous emission noise containing bothquadrature phase components and both polarizations (4 DOFs), but the 2 DOF casewould result if a polarization filter were used. Although the 1 and 2 DOF cases are of lesspractical interest than the 4 DOF case, they provide useful benchmarks for comparingperformance limits.We evaluate both spectral efficiency limits (bps/Hz) in the limit of high and low SNR forthe 1,2 and 4 DOF cases and also find the power efficiency (minimum number of photonsper bit) for each of these cases. It is shown that for high SNR the spectral efficiency is thesame independent of the number of DOFs and that the half-Gaussian distribution..,..tested for theQ1 PC1 bus cardBoth these projects mere sofixare des elopment efforts tonards contributing to dlfferentaspects of Roboucs and lZ1echatronics projects m the Controls and Roboucs Group..
Subject	:	Electericl tess
	:	برق
electronic file name	:	TL45201.pdf
Title and statement of responsibility and	:	Influence of the Number of Degrees of Freedom on the Capacity of Incoherent Optical Fiber Communication Systems [Thesis]