A transceiver operative to transmit and receive optical signals, comprising: - a laser operative to generate a continuous wavelength; - a power splitter operative to receive the continuous wavelength from the laser and to split the continuous wavelength into a first portion and a second portion; - a dual-polarization in-phase and quadrature modulator, DP-IQM, operative to receive the first portion of the continuous wavelength from the power splitter and to modulate the first portion of the continuous wavelength according to a modulation format, thereby producing a first modulated signal; - a first circulator (C1, C3) operative to receive the first modulated signal from the DP-IQM and to transmit the first modulated signal through a full-duplex fiber; - a second circulator (C2, C4) operative to receive the second portion of the continuous wavelength, which is the first unmodulated signal, from the power splitter and to transmit the first unmodulated signal through the full-duplex fiber; the first circulator (C1, C3) being further operative to receive a second unmodulated signal from the full-duplex fiber and the second circulator (C2, C4) being further operative to receive a second modulated signal from the full-duplex fiber; - a first optical polarization controller, PC, operative to receive the second unmodulated signal from the first circulator (C1, C3), and to adjust a polarization state of the second unmodulated signal, thereby producing a polarization state adjusted unmodulated signal; - a second optical polarization controller operative to receive the second modulated signal from the second circulator (C2, C4) and to adjust the polarization state of the second modulated signal, thereby producing a polarization state adjusted modulated signal; and - a dual-polarization coherent receiver, DP-CRx, operative to receive, through a signal port, the polarization state adjusted modulated signal and, through a local oscillator port, the polarization state adjusted unmodulated signal, the DP-CRx being configured to perform coherent detection of modulating information and to generate four electrical output signals. - a laser operative to generate a continuous wavelength; - a power splitter operative to receive the continuous wavelength from the laser and to split the continuous wavelength into a first portion and a second portion; - a dual-polarization in-phase and quadrature modulator, DP-IQM, operative to receive the first portion of the continuous wavelength from the power splitter and to modulate the first portion of the continuous wavelength according to a modulation format, thereby producing a first modulated signal; - a first circulator (C1, C3) operative to receive the first modulated signal from the DP-IQM and to transmit the first modulated signal through a full-duplex fiber; - a second circulator (C2, C4) operative to receive the second portion of the continuous wavelength, which is the first unmodulated signal, from the power splitter and to transmit the first unmodulated signal through the full-duplex fiber; - a first optical polarization controller, PC, operative to receive the second unmodulated signal from the first circulator (C1, C3), and to adjust a polarization state of the second unmodulated signal, thereby producing a polarization state adjusted unmodulated signal; - a second optical polarization controller operative to receive the second modulated signal from the second circulator (C2, C4) and to adjust the polarization state of the second modulated signal, thereby producing a polarization state adjusted modulated signal; and - a dual-polarization coherent receiver, DP-CRx, operative to receive, through a signal port, the polarization state adjusted modulated signal and, through a local oscillator port, the polarization state adjusted unmodulated signal, the DP-CRx being configured to perform coherent detection of modulating information and to generate four electrical output signals. <EOS>