High-speed PAM4-based optical SDM interconnects with directly modulated long-wavelength VCSEL

Joris Van Kerrebrouck, Xiaodan Pang, Oskars Ozolins, Rui Lin, Aleksejs Udalcovs, Lu Zhang, Haolin Li, Silvia Spiga, Markus Christian Amann, Lin Gan, Ming Tang, Songnian Fu, Richard Schatz, Gunnar Jacobsen, Sergei Popov, Deming Liu, Weijun Tong, Guy Torfs, Johan Bauwelinck, Jiajia ChenXin Yin

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


This paper reports the demonstration of high-speed PAM-4 transmission using a 1.5-μm single-mode vertical cavity surface emitting laser (SM-VCSEL) over multicore fiber with 7 cores over different distances. We have successfully generated up to 70 Gbaud 4-level pulse amplitude modulation (PAM-4) signals with a VCSEL in optical back-to-back, and transmitted 50 Gbaud PAM-4 signals over both 1-km dispersion-uncompensated and 10-km dispersion-compensated in each core, enabling a total data throughput of 700 Gbps over the 7-core fiber. Moreover, 56 Gbaud PAM-4 over 1-km have also been shown, whereby unfortunately not all cores provide the required 3.8 × 10 -3 bit error rate (BER) for the 7% overhead-hard decision forward error correction (7% OH-HDFEC). The limited bandwidth of the VCSEL and the adverse chromatic dispersion of the fiber are suppressed with pre-equalization based on accurate end-to-end channel characterizations. With a digital postequalization, BER performance below the 7% OH-HDFEC limit is achieved over all cores. The demonstrated results show a great potential to realize high-capacity and compact short-reach optical interconnects for data centers.

Original languageEnglish
Article number8489953
Pages (from-to)356-362
Number of pages7
JournalJournal of Lightwave Technology
Issue number2
StatePublished - 15 Jan 2019


  • 4-level pulse amplitude modulation (PAM-4)
  • Direct detection
  • digital signal processing (DSP)
  • multicore fiber (MCF)
  • spatial division multiplexing (SDM)
  • vertical cavity surface emitting laser (VCSEL)


Dive into the research topics of 'High-speed PAM4-based optical SDM interconnects with directly modulated long-wavelength VCSEL'. Together they form a unique fingerprint.

Cite this