Employing Prism-Based Three-Spot Mode Couplers for High Capacity MDM/WDM Transmission

Based on a three-surface prism, a free space design of the three-spot mode coupler, supporting LP01 and LP11 modes, is introduced in this letter. We demonstrate 7.68 Tbit/s transmission of three mode division multiplexing (MDM) × 8 wavelength division multiplexing (WDM) × 320-Gb/s dual-polarization (DP)-32QAM over a 120 km differential-group-delay (DGD)-compensated few-mode fiber (FMF) by employing the proposed spot couplers.