16-QAM ALL-OPTICAL OFDM SYSTEM PERFORMANCE EVALUATION WITH TIME AND FREQUENCY OFFSETS

In an all-optical orthogonal frequency division multiplexing (AO-OFDM) system, symbol time misalignment (STM) and subcarrier frequency offset (ScFO) between transmitter and receiver result in intercarrier interference (ICI) and intersymbol interference, leading to a degradation of the system performance. In this article, an analytical study of the impacts of STM and ScFO on the bit error rate (BER) performance of superchannel based on 16-QAM modulated all-optical OFDM transmitter with coherent detection is conducted. Under the condition BER=10(-3), maximum acceptable relative deviations for the STM and ScFO are 3.2 and 5.5% in AO-OFDM system. A delay line interferometer (DLI)-based ICI suppression method is proposed, and the results demonstrate that the tolerances to relative deviations for the STM and ScFO increase to 29 and 10% without cyclic prefix. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1593-1597, 2015