432-Gbps DP-QPSK transmission over multi-core fiber with low complexity self-coherent receiver

In this paper, we propose a novel approach with extremely low complexity for digital signal processing (DSP) at the receiver end. The frequency offset compensation (FOC) and carrier phase recovery (CPR) are omitted due to the self-coherent system. Multiple-input multiple-output free (MIMO-free) operation is achieved by adaptive polarization controller (APC). Therefore, a self-coherent transmission system has been successfully demonstrated experimentally over an 81 km distance, of which the first kilometer uses 7-core fiber and the remaining 80km uses standard single mode fiber (SSMF), using an 18-GBaud dual-polarization quadrature phase shift keying (DP-QPSK) signal. The center of the 7-core fiber transmitted the local oscillator (LO), while its side core transmitted the QPSK signal. This allows rapid polarization tracking of remotely delivered LO and separately delivered signal. Simultaneously, space division multiplexing (SDM) technology was employed to transmit signals in multiple channels to achieve the purpose of capacity expansion. In the experiment, a simplified self-coherent QPSK transmission system with a capacity of 432Gbps (6 × 72 Gbps) was realized.