Optical spectral reshaping for directly modulated 4-pulse amplitude modulation signals

Oskars Ozolins, Francesco Da Ros, Valentina Cristofori, Xiaodan Pang, Richard Schatz, Mohamed E. Chaibi, Laurent Bramerie, Sergei Popov, Michael Galili, Leif Katsuo Oxenløwe, Christophe Peucheret, Gunnar Jacobsen

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The tremendous traffic growth in intra/inter-datacenters requires low-cost high-speed integrated solutions [1]. To enable a significantly reduced footprint directly modulated lasers (DMLs) have been proposed instead of large external modulators. However, it is challenging to use DMLs due to their low dispersion tolerance and limited achievable extinction ratio (ER). A promising solution to this problem is optical spectral reshaping (OSR) since it is possible to increase the dispersion tolerance as well as to enhance the achievable ER for both on-of-keying [2] and 4-pulse amplitude modulation (PAM) [3] signals. However, moving to 4-PAM,many of the impressive demonstrations reported so far rely heavily on off-line digital signal processing (DSP), which increases latency, power consumption and cost. In this talk, we report on (i) a detailed numerical analysis on the complex transfer function of the optical filter for optical spectral reshaping in case of pulse amplitude modulation and(ii) an experimental demonstration of real-time dispersion-uncompensated transmission of 10-GBd and 14-GBd 4-PAM signals up to 10- and 26-km SSMF. This is achieved by combining a commercial 10-Gb/s DML with optical spectral shaping, thus removing the need for any complex off-line DSP and improving dispersion tolerance. These achievements are enabled by OSR based on a passive microring resonator fabricated on the SOI platform [4]. Significant improvement in receiver sensitivities was observed for both a 10-GBd signal after 10-km SSMF transmission and 14-GBd with no penalty after 26-km SSMF transmission.
Original languageEnglish
Title of host publicationProceedings:of the 19th International Conference on Transparent Optical Networks
Publication date2017
ISBN (Print)9781538608593
Publication statusPublished - 2017
Event19th International Conference on Transparent Optical Networks - Girona, Spain
Duration: 2 Jul 20176 Jul 2017


Conference19th International Conference on Transparent Optical Networks


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