Short Reach Communication Technologies for Client-Side Optics Beyond 400 Gbps

Short reach optical communication technologies are increasingly demanded in several fast-evolving application scenarios in both telecom and datacom. Low-cost and low-complexity intensity modulation and direct detection (IM/DD) technologies are challenged to scale up the link rate beyond 400 Gbps by increasing the single-lane rate towards 200 Gbps, to maintain a low lane count in client-side optics. Limited by the bandwidth of both electronics and optoelectronics, and the more pronounced chromatic dispersion in the fiber, such high baud rate systems require the use of digital signal processing techniques with forward error correction (FEC) coding. Therefore, in this work, we first summarize a few potential alternative technologies to the IM/DD for future development and then focus on extending the IM/DD systems towards 200 Gbps lane rate. We study both their capability and their performance limits using numerical simulations and transmission experiments.