Mode Exchange of High-speed DP-QPSK Signals Using Spatial Light Modulator

Mode exchange (ME) can effectively improve the utilization of network resources in short-distance mode division multiplexing (MDM) communication systems. In this paper, we proposed a method for the ME of dual-polarization (DP) signals using a single spatial light modulator (SLM) along with one half-wave plate (HWP) and two mirrors, without additional polarization diversity devices. The channel exchange between LP
01
- and LP
11
-mode 100 Gb/s dual-polarization quadrature phase shift keying (DP-QPSK) signals is experimentally implemented and the receiver sensitivities of the output LP
01
-mode channels before and after ME are also measured. It is shown that the polarization-dependent loss (PDL) is less than 2 dB for the LP
01
-mode channels and the mode exchange can bring about the receiver sensitivity degradation of 2 dB. The effectiveness and practicability of the proposed method are desirable for the real-time transmission and exchange of high-speed DP signals in multiple-input multiple-output free (MIMO-free) MDM systems.