Coherent optical receiver

A coherent optical receiver intended to receive an amplitude-shift keying modulated optical signal from a coherent optical transmitter, comprising:

• a local oscillator;
• a polarization-diversity actuator configured for modifying an optical signal output by the local oscillator;
• so as to form an optical signal with elliptical polarization with main axis orientation φl and ellipticity phase shift ψl;
• a 2×2 coupler, having one input aiming at receiving the amplitude-shift keying modulated optical signal received from the coherent optical transmitter and the other input receiving another optical signal which is output by a set formed by a local oscillator and the polarization diversity actuator, so as to enable the local oscillator to provide a boosting effect to the amplitude-shift keying modulated optical signal received from the coherent optical transmitter, the 2×2 coupler further having one output connected to a set formed by a photodiode followed by a Direct Current filter removing a continuous component of an analog electrical signal output by the photodiode;
• a transimpedance amplifier converting current electrical signal output by the Direct Current filter into voltage electrical signal;
• a controlling unit in form of electronic circuitry configured for performing a domain-switching procedure instructing a configuration change of the polarization diversity actuator by modifying the ellipticity main axis orientation φl and/or the ellipticity phase shift ψl when the voltage electrical signal output by the transimpedance amplifier is below or equal to a predetermined first threshold THdsp corresponding to a predetermined percentage of theoretical maximum achievable by the boosting effect,
• and wherein the electronic circuitry is further configured for performing a phase-refining procedure inserting a controlled error signal in the phase of the optical signal output by the set formed by the local oscillator and the polarization diversity actuator, and adjusting a static component of the controlled error signal toward a maximum voltage electrical signal output by the transimpedance amplifier.