Forward Error correcting Code design (FEC) and implementation for optical feeder link is reported. The designed LDPC codes present very good performances (BER < 1e-9) while requiring less than 20% hardware resources of FPGA compatible with space constraints. Protection scheme based on these LDPC codes combined with a physical layer bit interleaver is presented. Links sizing for GEO optical feeder link at 30° elevation angle under strong turbulence shows that uplink might require up to 100W per link.