The Evaluation for Required Bit Resolution of Digital-Analog-Converter in Optical OFDM Signal Generation

Hidenori TAKAHASHI  Itsuro MORITA  Hideaki TANAKA  

Publication
IEICE TRANSACTIONS on Communications   Vol.E94-B   No.2   pp.425-429
Publication Date: 2011/02/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E94.B.425
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Extremely Advanced Optical Transmission Technologies and Transmission Optical Fiber Technologies towards Exabit Era)
Category: 
Keyword: 
OFDM,  DAC,  resolution,  

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Summary: 
The required bit resolution of digital-analog-converter (DAC) for optical OFDM was evaluated through simulation and experiment. We found that the signal degradation caused by quantization depends on the number of subcarriers theoretically, but the other noise generated in experiment suppresses the dependency. Additionally, signal degradation caused by quantization is independent of subcarrier modulation, and the performance improvement saturates with increasing bit resolution. With the criteria for the BER of 110-3, the required DAC resolution by simulation with ideal analog-digital-converter at receiver is 3 bits for QPSK, 4 bits for 8-QAM and 5 bits for 16-QAM and 32-QAM. From the experimental result, the required bit resolution is increased as 6 bits for 32-QAM.