The embodiment of the invention provides a generalized frequency division multiplexing system, an optical fiber signal generation method and an optical fiber signal generation device. The method comprises the following steps: acquiring an original signal sent by a signal source; performing probability shaping processing on the original signal, and determining an output sequence; layering the output sequence to obtain a plurality of layered output sequences; carrying out lDPC coding processing on each layered output sequence to obtain an information sequence corresponding to each layered outputsequence; and mapping the information sequence corresponding to each layered output sequence to a constellation diagram according to a preset probability distribution rule to obtain an optical fibersignal of the GFDM system. By applying the technical scheme provided by the embodiment of the invention, the GFDM system optical fiber signal can be obtained through probability forming and a variablecode rate LDPC coding technology, the energy loss of signal transmission is reduced, the coding efficiency is improved, and the error code performance and the channel capacity are improved.