Study of Self-Homodyne Coherent System Using Multicore Fiber for Data Center Links

The demand for information capacity in data center networks has grown exponentially during past decades. Such growth promotes consideration for adoption of coherent transmission technologies in this application space to achieve current and future high data rate requirements at 400G, 800G, and higher. Coherent systems offer higher capacity than direct detection systems using more degrees of freedom to carry information, but with higher system complexity. To meet the cost and power consumption requirements for data center transceivers, coherent-lite technologies have been proposed. Among them, self-homodyne coherent (SHC) is a promising candidate which allows the use of low cost lasers and simplifies digital signal processing (DSP). We study SHC systems and focus on the use of a multicore fiber (MCF) to obtain small channel skew, which allows for further simplification of DSP. We observe and manage stimulated Brillouin scattering (SBS) effects in the local oscillator path. We analyze the optimal power split ratio between the data path and the local oscillator path to maximize data capacity. Moreover, we compare the channel skew and transmission performance between multicore fiber and ribbon fiber. SHC with MCF delivers high data capacity with significant complexity reduction, which may be a promising solution for data center links.