Multi-Dimensional Adaptive Transmission Technology for Medium and Short Distance Optical Fiber Communication Systems

Based on the characteristics of medium-distance optical fiber communication systems using Erbium Doped Fiber Amplifier (EDFA), semiconductor laser, photo sensor(optical detector) with 2A/W responsivity, three high-performance adaptive modulation and coding techniques are studied. The first scheme introduces forward error correction (FEC) coding dimensions on the basis of the traditional bit and power loading (BPL) to realize three-dimensional adaptive modulation and coding. This algorithm is based on a look-up table to allocate modulation and coding formats, which has lower complexity and higher transmission rate than the BPL algorithm. However based on the look-up table, the second scheme uses block precoding to achieve the same rate as the traditional BPL, but reduces the signal power peak-to-average ratio by up to 2 dB and improves power efficiency. The third scheme uses probabilistic shaping (PS) QAM as the modulation format, at the cost of reasonable complexity in exchange to shaping gain and almost infinitely fine modulation granularity. Rely on adaptive block precoding, without reducing the rate; limit the number of PS-QAM to reduce complexity. Experiments show that the third scheme achieves a much better rate and higher receiver sensitivity than the BPL scheme.