Arrayed-wave guide grating multi/demultiplexer with loop-back optical paths

Claim 1

An optical multiplexing/demultiplexing device, having loop-back paths constituted by a plurality of optical path means, for performing wavelength multiplexing and demultiplexing of an optical signal consisting of a plurality of wavelengths by separating said optical signal into individual wavelengths and propagating each wavelength separately in each of said optical path means, said device comprising: a. an arrayed waveguide grating multi/demultiplexer device, comprising an arrayed waveguide grating; a plurality of input sections for receiving said optical signals; a plurality of output sections for outputting optical signals; a slab waveguide for distributing or coupling wavelength signals optically disposed between said plurality of input sections and said waveguide grating, and another slab waveguide for distributing or coupling wavelength signal optically disposed between said plurality of output sections and said arrayed waveguide grating; and b. a plurality of loop-back optical path means for propagating and looping optical signals comprising said plurality of optical path means and having signal processing means disposed on selected ones of the optical path means; wherein said arrayed waveguide grating, a plurality of input sections, a plurality of output sections, and said slab waveguides are integrally fabricated on a common substrate base functioning as the arrayed waveguide grating multi/demultiplexer device, and said loop-back optical path means are optically connected with said plurality of input sections and with said plurality of output sections to propagate a wavelength signal from said plurality of output sections into at least one input section of said plurality of corresponding input sections to loop said wavelength signal at least once in one optical path means of said loop-back paths, thereby performing multiplexing and demultiplexing and signal time delay operations using said array waveguide grating multiplexer-demultiplexer device having loop-back paths.