Ultra-high Bandwidth efficient Implementation Employing Geometric Shaped Symbol Division Multiplexing in Optical DMT Interconnection

A channel coded modulation scheme based on hybrid geometric shaped symbol division multiplexing (GS-SDM) is proposed and experimentally demonstrated in intensity modulation and direct detection discrete optical discrete multi-tone (DMT) interconnection system with ultra-high bandwidth efficiency (BE) enhancement. By GS multiplexing of up to eight symbols of 64 quadrature amplitude modulation (QAM) on every single complex constellation point, a newly formed SDM-12QAM with 6-bit symbol capacity achieves extra enhancement for symbol carrying data rate by 67% as well as the BE implementation, compared with typical modulation format at identical symbol rate. For SDM de-multiplexing (De-SDM), an iteratively de-modulation cooperated with low-density parity-check decoding is proposed to retrieve the multiplexed overlapping symbols in GS-SDM symbols. The experimental results reveal that, when the 100Gb/s DMT signals are transmitted over standard single mode fiber, the proposed GS-SDM signal can effectively improve the received power sensitivity by 3.3 dB, under conditions of significantly avoidance of the impairments by fiber chromatic dispersion and Kerr nonlinearity optimization.