OPTICAL DETECTOR FOR DETECTING OPTICAL SIGNAL BEAMS, METHOD TO DETECT OPTICAL SIGNALS, AND USE OF AN OPTICAL DETECTOR TO DETECT OPTICAL SIGNALS

摘要

An optical detector for detecting an optical signal beam (OSB) modulated in a way that it includes an in-phase and/or a quadrature component, includes: a polarisation beam splitter arranged to split the OSB into two polarised OSBs; a non-polarisation beam splitter arranged to further split each of the two polarised OSBs into two split polarised OSBs; at least one birefringent element providing a phase shift, the birefringent element being arranged in a path of at least one polarised OSB and/or in a path of at least one split polarised OSB so that an in-phase and quadrature phase offset between two split polarised OSBs originating from the same polarised OSB is formed in output signal beams; and at least two detection means arranged to receive at least one output signal beam that includes a in-phase and/or quadrature component of the OSB.