METHOD AND OPTICAL NETWORK FOR ESTABLISHING A BIDIRECTIONAL TRAFFIC RELATIONSHIP BETWEEN AT LEAST ONE EDGE NODE AND A FIRST AND SECOND CORE NODE

The invention relates to an optical network for establishing a bidirectional traffic relationship between at least one edge node (202) and a first and second core node (204, 208), the at least one edge node (202) comprising an optical transmitter (214), an optical receiver (216) and an optical coupler device (218A, 218B), wherein the optical coupler device (218A, 218B) is configured to optically couple a first remote port (222) of the at least one edge node (202) to a remote port (226) of the first core node (204) and a second remote port (224) of the at least one edge node (202) to a remote port (228) of the second core node (206) via an optical path (208). The optical network is characterized in that the optical transmitter (214) is configured to create a combined upstream optical signal (Uopt) comprising a first upstream optical channel signal (U1,opt) at a first optical center frequency for establishing the traffic relationship with the first core node (204) and a second upstream optical channel signal (U2,opt) at a second differing optical center frequency for establishing the traffic relationship with the second core node (206), the optical transmitter (214) comprising a single light source and being configured to create the first and second upstream optical channel signal (U1,opt, U2,opt) using a sub-carrier modulation technique by directly modulating the single optical source or by modulating the optical signal created by the single optical source using a single optical modulator, and that the optical receiver (216) is configured to receive a combined downstream optical signal (Dopt) at a receiving port of the optical receiver, the combined downstream optical signal comprising a first downstream optical channel signal (D1,opt) created by the first core node (204) at a third optical center frequency and a second downstream optical channel (D2,opt)signal created by the second core node (206) at a fourth optical center frequency different from the third optical center frequency, wherein the optical receiver (216) is configured to use a sub-carrier demodulation technique for receiving the combined downstream optical signal (Dopt), wherein the optical coupler device (218A, 218B) is configured to split the combined upstream optical signal (Uopt) and to feed it to both the first and second remote port (222, 224) and wherein the optical coupler device (218A, 218B) is configured to receive the first and the second downstream optical channel signals (D1,opt,