|標題:||Theoretical and Experimental Investigations of Direct-Detected RF-Tone-Assisted Optical OFDM Systems|
Arbab, Vahid R.
Christen, Louis C.
Willner, Alan E.
Department of Photonics
|關鍵字:||Direct detection;optical fiber communication;optical modulation;orthogonal frequency-division multiplexing (OFDM)|
|摘要:||In this paper, we propose and experimentally demonstrate a radio frequency (RF)-tone-assisted optical orthogonal frequency-division multiplexing (OFDM) transmission. By inserting an RF tone at the edge of the signal band and biasing the Mach-Zehnder modulator (MZM) at the null point, the proposed system has a better sensitivity and chromatic dispersion (CD) tolerance compared to the previous intensity-modulated single-sideband OFDM (SSB-OFDM). We show analytically that the majority of the linear channel impairments, such as the transmitter, CD, optical filtering, and receiver, can be compensated for by a simple zero-forcing equalizer. Besides, the optimum value of the important parameter, carrier-to-signal-power ratio (CSPR), is analytically obtained and supported via the experimental results. We also observe that the relatively worse sensitivity of the previous SSB-OFDM can be attributed to the limited CSPR. We experimentally demonstrate a 10-Gb/s, 8 quadrature-amplitude modulation (QAM) RF-tone-assisted OFDM transmission, and show that our system has a similar to 5-dB better sensitivity compared to the previous intensity-modulated SSB-OFDM and exhibits a negligible transmission penalty after 260-km uncompensated standard single-mode fiber (SSMF).|
|期刊:||JOURNAL OF LIGHTWAVE TECHNOLOGY|
|Appears in Collections:||Articles|
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