Cycle slip resilient coded modulation for fiber-optic communications

A receiver for receiving and decoding an optical data signal, said optical data signal having phase and amplitude modulation according to a constellation diagram with at least eight constellation points representing non-binary symbols, said receiver comprising:

• at least one phase recovery unit for carrying out a carrier phase recovery of a received signal ignoring the occurrence of cycle slips, said cycle slips corresponding to unwanted abrupt phase jumps congruent with the rotational symmetry of the constellation, and
• a decoder for decoding said signal after carrier phase recovery, wherein the decoder is configured such that in said decoding, cycle slips occurring during carrier phase recovery are modelled as virtual equivalent phase slip input to an equivalent encoder assumed by the decoding scheme, wherein said equivalent encoder operates such that for each symbol
• the encoding result of the symbol with a given equivalent phase slip input, and
• the encoding result of the same symbol with zero equivalent phase slip input but subjected to a true cycle slip of a phase angle corresponding to said given equivalent phase slip
• is identical.