Experimental Study of 1.55-μm EML-Based Optical IM/DD PAM-4/8 Short Reach Systems

Xiaodan Pang, Oskars Ozolins, Simone Gaiarin, Aditya Kakkar, Jaime Rodrigo Navarro, Miguel Iglesias Olmedo, Richard Schatz, Aleksejs Udalcovs, Urban Westergren, Darko Zibar, Sergei Popov, Gunnar Jacobsen

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We experimentally evaluate high-speed intensity modulation/direct detection (IM/DD) transmissions with a 1.55-μm broadband electro-absorption modulated laser and pulse amplitude modulations (PAM). We demonstrate 80 Gb/s/λ PAM-4 and 96 Gb/s/λ PAM-8 transmissions with low-complexity digital equalizers at the receiver. Performance comparison with different types of equalizers are performed, including linear symbol-spaced feed-forward equalizer (FFE), fractional (half-symbol) spaced FFE and decision feedback equalizer (DFE), with different tap number. It is found that for both cases, a 6-tap symbol-spaced FFE is sufficient to achieve a stable performance with bit-error-rate below the 7% overhead hard decision forward error correction (7%-OH HD-FEC) threshold over a 4 km standard single mode fiber link. Practical considerations including comparison between adaptive and static equalizer implementation and tolerable fiber chromatic dispersion are discussed.
Original languageEnglish
JournalIEEE Photonics Technology Letters
Issue number6
Pages (from-to)523-6
Publication statusPublished - 2017

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  • Distributed feedback laser (DFB)
  • Direct detection
  • Electroabsorption modulator
  • Optical interconnects


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