Patent ID: 7068885

Claim:
A planar lightwave circuit wavelength division multiplexer/demultiplexer device comprising: a slab waveguide defining first and second slab regions connected by a gap; first and second face to face concave reflective diffraction gratings on either end of the slab waveguide; a first waveguide extending to the first slab region; a second waveguide extending to the first slab region; and a third waveguide extending to the second slab region; wherein the first and second reflective gratings and the ends of the first, second and third waveguides are positioned, whereby light of a wavelength in a first range of wavelengths will pass between the first and second waveguides via the first grating, and whereby light of a wavelength in a second range of wavelengths, higher or lower than the first range of wavelengths, will pass between the first and third waveguides via the first and the second grating.