EML based real-time 112 Gbit/s (2 × 56.25 Gbit/s) PAM-4 signal transmission in C-band over 80 km SSMF for inter DCI applications

• Published in: Optical fiber technology 2018-11, Vol.45, p.141-145
• Main Authors: Lee, Jie Hyun, Chang, Sun Hyok, Huh, Joon Young, Kang, Sae-Kyoung, Kim, Kwangjoon, Lee, Joon Ki
• Format: Article
• Language: English
• Subjects: Datacenter; Electro-absorption modulator integrated laser; PAM-4 modulation
• ISSN: 1068-5200; 1095-9912
• DOI: 10.1016/j.yofte.2018.06.007

•For inter-DCI applications, a cost effective solution for high capacity transmission over 80 km SSMF is required.•In this paper, the optimal driving conditions of electro absorption modulated integrated lasers are investigated for transmitting real-time PAM-4 optical signal over 80 km SSMF.•The required OSNR and dispersion tolerance as a function of EAM driving conditions are measured and utilized for transmitting 100 Gigabit Ethernet traffic.•This technique can be applied for optimizing multi-level modulation transmission which use optical transmitter with non-linear transfer curve. We report on an electro-absorption modulator (EAM) integrated laser (EML) based real-time 112 Gbit/s (2 × 56.25 Gbit/s) 4-level pulse amplitude modulation (PAM-4) signal transmission in the C-band over 80 km of standard single-mode fiber (SSMF). Various operating conditions of the EAM were investigated to find the optimum driving conditions for PAM-4 modulation. When the EAM reverse bias was set to the inflection point of the transfer curve, which was −2.35 V, we obtained a bit error ratio (BER) of 4 × 10−8, which is well below the forward error correction (FEC) limit. The results demonstrate the feasibility of using EMLs for implementation in PAM-4 transceivers for inter-datacenter interconnection (inter-DCI) applications.