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Authors
Affiliations
1 Guru Nanak Dev Engineering College, Ludhiana, IN
Source
Digital Signal Processing, Vol 3, No 5 (2011), Pagination: 198-203
Abstract
We investigate the complex interaction between direct detection and coherent detection optical-OFDM systems at 10 Gb/s and 4-QAM. We show how fibre dispersion causes different quadrature amplitude modulation (QAM) constellation phase rotations as a function of OFDM sideband frequency. We investigated that in case of DDO-OFDM we need to extend constellation amplitude up-to 2m whereas in CDO-OFDM it is limited to 1m. In case of DDO-OFDM double side band is produced which makes lot of bandwidth wastage. We also investigate that Carrier boosting at the receiver enables direct detection optical OFDM (DDO-OFDM) to outperform coherent OOFDM in the nonlinear limit.
Keywords
Optical-Orthogonal Frequency Division Multiplexing (O-OFDM), Direct Detection Optical-Orthogonal Frequency Division Multiplexing (DDO-OFDM), Coherent Detection Optical-Orthogonal Frequency Division Multiplexing (CDO-OFDM), Quadrature Amplitude Modulation (QAM), Fast Fourier Transform (FFT).
