Optical-electrical switching node

An electro-optical switch configured to;

• (i) receive N data streams on an optical link from a first node in a communications system, each of said N data streams having an amplitude and a phase and each being located at an optical centre frequency FO1+RFM, where Fo1 is a first optical modulation frequency and RFM is a signal centre frequency, where M is an integer which ranges from 1 to N for the N data streams;
• (ii) convert at least a first of the N data streams on said optical link to a first electrical data signal at the data stream's signal centre frequency RFM, the first electrical data signal having the amplitude and phase of the first data stream on the optical link;
• (iii) convert the first electrical data signal to a first optical output signal at an optical centre frequency FO2+RFOUT with the amplitude and phase of the first electrical data signal maintained, where FO2 is a second optical modulation frequency;
• and
• (iv) forward the first optical output signal to a second node in the communications system, with RFM, and RFOUT being equal to or different from each other, and FO1 and FO2 also being equal to or different from each other.