Method and system for modulating the data for optical communications

Method first modulates the data for optical communications by encoding data using a Forward Error Correction (FEC) encoder for generating an encoded data, the encoded data It is encoded using the block encoder to generate the data block coding as the Hamming distance between codewords representing the data block coding is increased. Data block coding, as the Euclidean distance between constellation points increases are mapped to generate a mapped data. Thereafter, the mapped data is modulated into a modulation signal for the optical channel at the transmitter.