Evaluation of optical MIMO transmissions through multicore fiber links with an optical switch

Multiple-input and multiple-output (MIMO) signal processing technique has been introduced to eliminate the interference caused by crosstalk along Space Division Multiplexing (SDM) links. In optical networks, optical paths are set between end-to-end nodes via several switches. Optical switches connect light signals using appropriate switching rules. Consequently, different combinations of light signals transmitted through several coupled Multi-Core Fibers (MCFs) along an end-to-end optical path. In turn, this type of optical transmission results in an increased complexity with respect to the MIMO signal processing at the receiver and also in a reduced transmission capacity of the entire communication system. To analyze this issue in detail, an optical MIMO network model with MCFs and optical switch was considered, and the eigenvalue distribution of channel matrix along with average capacity of MCF links was discussed. The analysis showed that the optical switch disperses the eigenvalue distribution of channel matrix and reduces the capacity by approximately 15% for SDM network with MCFs. This degradation rate is increased noticeably for larger crosstalk in MCF links and is increased moderately with an increasing number of switches.