InP-based On-board Coherent Tx Front-end with 100-GHz Bandwidth Utilizing Flip-chip Technology Enabling 2-Tb/s/λ Optical Transmission

• Published in: Journal of lightwave technology 2024-10, p.1-7
• Main Authors: Wakita, Hitoshi, Nagatani, Munehiko, Ogiso, Yoshihiro, Nakamura, Masanori, Hamaoka, Fukutaro, Shiratori, Yuta, Kobayashi, Takayuki, Miyamoto, Yutaka, Takahashi, Hiroyuki
• Format: Article
• Language: English
• Subjects: Bandwidth; Coherent Tx front-end; Connectors; flip-chip bonding; High-speed optical techniques; III-V semiconductor materials; Indium phosphide; InP-HBT-based driver IC; InP-MZMs; Integrated optics; Modulation; on-board assembly; Optical modulation; Optical transmitters; print circuit board; Substrates
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2024.3472732

We present a 100-GHz-bandwidth coherent transmitter (Tx) front-end consisting of a cost-effective PCB with a flip-chip-bonded InP-HBT-based driver IC and InP-MZM-based optical IQ modulator, which enables net 2.11- and 2.03-Tb/s/λ 80-km optical transmission. Achieving this 100-GHz bandwidth requires the use of wideband driver ICs and optical modulators as well as the implementation of a low-loss substrate and broadening the bandwidth of the interconnections between the chips and the substrate. We demonstrated the importance of such assembly technology by using a low-loss substrate with a dielectric constant of 3.06 and a dielectric loss tangent of 0.002 as the platform and flip-chip bonding, which reduces parasitic inductance, to achieve the desired wideband performance. To the best of our knowledge, this is the first demonstration of 100-GHz bandwidth and over 2-Tb/s/λ transmission using a coherent Tx front-end.