Based on the multiple spatial mode channels of conventional multimode optical fiber,the optical fiber transmission system capacity can be effectively improved by adopting multi-dimensional multiplexing technology and then meet the rapidly growing demand for data services. In this paper,we demonstrate the conventional OM2 fiber based large-capacity optical transmission with a combination of wavelength division multiplexing (WDM),polarization division multi-plexing (PDM) and mode division multiplexing (MDM) technologies. Each of the total 80 channels with 40 wavelengths (1535.04～1566.31 nm) and 2 mode (LP01 and LP11b) channels is modulated by 60 Gbaud PDM16-ary quadrature ampli-tude modulation (PDM-16QAM) signal. The MDM link consists of a pair of mode multiplexer/de-multiplexer based on multi-plane light conversion (MPLC) and 20 m OM2 fiber. Thanks to the high mode isolation degree of two used mode channels (<-20 dB),only 2×2 multiple input multiple output (MIMO) algorithm is applied for polarization de-multiplexing,and no need to do mode de-multiplexing. In this work,to improve the system capacity,the key system parameters have been optimized,including the roll-off factor of pulse shaping filter,clipping ratio and the received optical power (ROP). And the Volterra decision feedback equalization (VDFE) is also adopted not only to compensate for the nonlinear impair-ments introduced by the optical modulator,but also alleviate the high frequency noise enhancement caused by feed forward equalization (FFE). Then,a total capacity up to 38.4 Tbit/s has been realized with the bit error rate (BER) of all 80 channels lowering than the 20％ soft decision forward error correction (SD-FEC) threshold of 2.7×10-2. The experimental results re-veal that the MDM coherent optical transmission scheme based on multi-mode fiber has the potential in the future ultra-large capacity short-distance optical interconnection system.
维普
万方数据