Latching optical switch and subsystem using bistable liquid crystal

A method for a reconfigurable branching unit BU for a submarine network using bistable liquid crystal BLC optical switching, comprising the steps of:

• configuring a submarine network with a branching unit BU for splitting or combining a signal between a main trunk path and a branch path for allowing signals from different paths to share a same fiber optic path, said BU and submarine network normally having a fixed and predetermined wavelength arrangement preventing reconfigurability of the submarine network;
• and
• employing a latching wavelength selective switch WSS or wavelength blocker WB in the branching unit for splitting or combining the signals between the main trunk path and branch path to enable a latching capability and enable reconfigurability of the branching unit BU, the latching WSSS being a bistable liquid crystal based material without moving parts for increased stability and lower power consumption over use of conventional mono-stable liquid crystal LC switches in a submarine network.