Methods and systems for optical communication in a submarine network are provided. An input signal is received from a terminal at a reconfigurable branching unit (BU), wherein the BU enables bidirectional transmission between any two terminals, and the input signal is demultiplexed into at least one individual waveband or wavelength using at least one demultiplexer. Each demultiplexed waveband is passed through optical switches, with corresponding optical switches for the same demultiplexed waveband provided for transmission in the reverse direction. Independent per-waveband switching is performed using a demultiplexer-switch-multiplexer (DSM) architecture. Each demultiplexed waveband is multiplexed at each output port using at least one multiplexer to combine signals from different sources, and combined signals are transmitted to a destination terminal.