Theoretical and Experimental Evaluation of Optimum Clipping Ratio for Optical OFDM

Orthogonal frequency division multiplexing (OFDM) has recently gained substantial interest in high capacity optical fiber communications. Unlike wireless systems, optical OFDM systems are constrained by the limited resolution of the ultra high-speed digital-to-analog converters (DAC) and analog-to-digital converters (ADC). Additionally, the situation is exacerbated by the large peak-to-average power ratio (PAPR) inherent in OFDM signals. In this paper, we study the effects of clipping and quantization noise on the system performance and derive a closed-form formula that links optimum clipping with the bit resolution of signal converters. © 2011 Optical Society of America OCIS codes: (000.0000) General. References and links 1. B. Schmidt, A. Lowery, and J. Armstrong, “Experimental demonstration of electronic dispersion compensation for long-haul transmission using direct-detection optical OFDM,” J. Lightwave Technol. 26, 196–203 (2008). 2. S. Jansen, I. Morita, T. Schenk, N. Takeda, and H. Tanaka, “Coherent optical 25.8-Gb/s OFDM transmission over 4160-km SSMF,” J. Lightwave Technol. 1, 6–15 (2008). 3. X. Jin, J. Tang, K. Qiu, and P. Spencer, “Statistical investigation of the transmission performance of adaptively modulated optical OFDM signals in multimode fiber links,” J. Lightwave Technol. 18, 3216–3224 (2008). 4. J. Armstrong, “OFDM for optical communcations,” J. Lightwave Technol. 27, 189–204 (2009). 5. Y. Benlachtar, P. Watts, R. Bouziane, P. Milder, D. Rangaraj, A. Cartolano, R. Koutsoyannis, J. Hoe, M. Püschel, M. Glick, and R. Killey, “Generation of optical OFDM signals using 21.4 GS/s real time digital signal processing,” Optics Express 17, 17658–17668 (2009). 6. N. Kaneda, Q. Yang, X. Liu, S. Chandrasekhar, W. Shieh, and Y.-K. Chen, “Real-time 2.5 GS/s coherent optical receiver for 53.3-Gb/s sub-banded OFDM,” J. Lightwave Technol. 28, 494–501 (2010). 7. R. Giddings, E. Hugues-Salas, X. Jin, J. Wei, and J. Tang, “Experimental demonstration of real-time optical OFDM transmission at 7.5 Gb/s over 25-km SSMF using a 1-GHz RSOA,” IEEE Photonics Technol. Lett. 22, 745–747 (2010). 8. F. Buchali, R. Dischler, A. Klekamp, M. Bernhard, and Y. Ma, “Statistical transmission experiments using a realtime 12.1 Gb/s OFDM transmitter,” in “Optical Fiber Communication Conference and Exposition,” (San Diego, CA, 2010). 9. R. Giddings, X. Jin, E. Hugues-Salas, E. Giacoumidis, J. Wei, and J. Tang, “Experimental demonstration of a record high 11.25 Gb/s real-time optical OFDM transceiver supporting 25 km SMF end-to-end transmission in simple IMDD systems,” Optics Express 18, 5541–5555 (2010). 10. Y. Benlachtar, P. Watts, R. Bouziane, P. Milder, R. Koutsoyannis, J. Hoe, M. Püschel, M. Glick, and R. Killey, “Real-time digital signal processing for the generation of optical orthogonal frequency-division-multiplexed signals,” IEEE J. Select. Topics Quantum Electronics 16, 1235–1244 (2010). 11. Y. Benlachtar, R. Bouziane, R. Killey, C. Berger, P. Milder, R. Koutsoyannis, J. Hoe, M. Püschel, and M. Glick, “Optical OFDM in the data center,” in “Proc. of Intl. Conf. on Transparent Optical Networks,” (Munich, Germany, 2010). 12. R. Bouziane, P. Milder, R. Koutsoyannis, Y. Benlachtar, C. Berger, J. Hoe, M. Püschel, M. Glick, and R. Killey, “Design studies for an ASIC implementation of an optical OFDM transceiver,” in “Proc. of European Conf. on Optical Communication,” (Torino, Italy, 2010). 13. D. Dardari, “Joint clip and quantization effects characterization in OFDM receivers,” IEEE Trans. Circuits and Systems–I 53, 1741–1748 (2006). 14. A. Papoulis and S. U. Pillai, Probability, Random Variables and Stochastic Processes (McGraw-Hill, New York, 2002).