A system comprising: a polarization state aligner, PSA, comprising: an input port ; a first polarization beam splitter, PBS, coupled to the input port; a first phase shifter, PS, coupled to the first output of the first PBS ; a first polarization rotator, PR, coupled to the second output of the first PBS ; a first beam splitter, BS, coupled to the first PS and the first PR ; a first output port coupled to the first BS ; and characterized by a second output port coupled to the first BS , a receiver coupled to the PSA and comprising: a second PBS ; a first 90 ° hybrid mixer coupled to the first output of the second PBS and the first output port of the first BS ; first photodiodes, PDs, coupled to the first 90° hybrid mixer ; first transimpedance amplifiers, TIAs, coupled to the first PDs ; and a digital signal processor, DSP, coupled to the first TIAs , wherein the receiver further comprises: a second PR coupled to the second output of the second PBS ; a second 90° hybrid mixer coupled to the second PR and the second output port of the first BS ; second PDs coupled to the second 90° hybrid mixer ; and second TIAs coupled to the second PDs and the DSP . a polarization state aligner, PSA, comprising: an input port ; a first polarization beam splitter, PBS, coupled to the input port; a first phase shifter, PS, coupled to the first output of the first PBS ; a first polarization rotator, PR, coupled to the second output of the first PBS ; a first beam splitter, BS, coupled to the first PS and the first PR ; a first output port coupled to the first BS ; and characterized by a second output port coupled to the first BS , an input port ; a first polarization beam splitter, PBS, coupled to the input port; a first phase shifter, PS, coupled to the first output of the first PBS ; a first polarization rotator, PR, coupled to the second output of the first PBS ; a first beam splitter, BS, coupled to the first PS and the first PR ; a first output port coupled to the first BS ; and characterized by a second output port coupled to the first BS , a receiver coupled to the PSA and comprising: a second PBS ; a first 90 ° hybrid mixer coupled to the first output of the second PBS and the first output port of the first BS ; first photodiodes, PDs, coupled to the first 90° hybrid mixer ; first transimpedance amplifiers, TIAs, coupled to the first PDs ; and a digital signal processor, DSP, coupled to the first TIAs , a second PBS ; a first 90 ° hybrid mixer coupled to the first output of the second PBS and the first output port of the first BS ; first photodiodes, PDs, coupled to the first 90° hybrid mixer ; first transimpedance amplifiers, TIAs, coupled to the first PDs ; and a digital signal processor, DSP, coupled to the first TIAs , wherein the receiver further comprises: a second PR coupled to the second output of the second PBS ; a second 90° hybrid mixer coupled to the second PR and the second output port of the first BS ; second PDs coupled to the second 90° hybrid mixer ; and second TIAs coupled to the second PDs and the DSP . a second PR coupled to the second output of the second PBS ; a second 90° hybrid mixer coupled to the second PR and the second output port of the first BS ; second PDs coupled to the second 90° hybrid mixer ; and second TIAs coupled to the second PDs and the DSP . <EOS>