POLARISATION-INDEPENDENT, OPTICAL MULTIPLEXING AND DEMULTIPLEXING SYSTEMS BASED ON FERROELECTRIC LIQUID CRYSTAL PHASE MODULATORS FOR SPATIAL MODE DIVISION MULTIPLEXING AND DEMULTIPLEXING

摘要

Multimode reconfigurable optical spatial mode multiplexing system (650) comprising: a first optical path (604a) to carry a first input beam from a first optical input (602a); a second optical path (604b) to carry a second input beam from a second optical input (602b); a beam combiner (612) to combine beams from said first and second optical paths and to provide a combined beam optical output; wherein at least one of said first and second optical paths is a phase modulating optical path and comprises a polarisation-independent reconfigurable phase modulator (608a, 608b) based on a ferroelectric liquid crystal spatial light modulator (FLC SLM) to impose a controllable phase profile on an input beam in the phase modulating optical path, so as to controllably convert a spatial mode order of the input beam from a lower order spatial mode to a higher order spatial mode; and further comprising a control input (620) to control said polarisation- independent reconfigurable phase modulator to configure said controllable phase profile, wherein said first and second input beams are combined into a multiple spatial mode combined beam optical output independent of a polarisation of said first and second input beams. The number of spatial modes of said combined beam is controllable with said control input to be higher than the number of spatial modes in either of said first and second input beams separately.