OPTICAL DEVICE

摘要

An optical device (10) for use in beamsplitting, recombination and related applications incorporates a rectangular multimode waveguide (20) connecting a first coupling waveguide (18) to two second coupling waveguides (22, 24). The first coupling waveguide (18) operates in its fundamental mode and provides an input which excites a series of symmetric modes of the multimode waveguide (20). Modal dispersion along the multimode waveguide (20) provides for the input excitation (70a) to be transformed into separate output excitations (75a, 75b) centred on respective second coupling waveguides (22, 24). The radiation intensity distribution (75) goes to zero at multimode waveguide end wall regions (54) between the second coupling waveguides (22, 24). This minimises reflection and increases beamsplitting efficiency. The device (10) may be operated in reverse as a beam combiner. Further embodiments include a phase-locked laser array (240) in which the second coupling waveguides (258) provide gain and a second multimode waveguide (260) provides phase correction.