Symmetric optical signal repeater

An optical signal repeater where an upstream modulator is configured to generate an optical upstream output signal by modulating an optical carrier signal, and to transmit the optical upstream output signal to an upstream fibre-optic output port. A downstream modulator is also configured to generate an optical downstream output signal by modulating an optical carrier signal and to transmit the optical downstream output signal to a downstream fibre-optic output port. By ensuring that the wavelengths of the optical carrier signals are equal or substantially equal, the wavelength drift in the upstream direction can be kept equal to the drift in the downstream direction. These repeaters can be used for time and frequency synchronization in long-distance fibre-optic networks.

Patent family as of 16.7.2026
EP4627741 A1, FI131616 B, FI20226064 A, US2026205198 AA, WO24115814 A1