Patent ID: 7330618

Claim:
An optical apparatus comprising: a slab waveguide in optical communication with; a plurality of input waveguides; and a plurality of output waveguides; CHARACTERIZED IN THAT: the plurality of input waveguides connected to a first end of the slab waveguide includes a number of active input waveguides and a number of dummy input waveguides; and the plurality of output waveguides connected to an opposing second end of the slab waveguide includes a number of active output waveguides and a number of dummy output waveguides; and a number of distinct optical paths exist between the active input waveguides and the active output waveguides; and wherein the total number of input waveguides is at least three times the number of active input waveguides; and wherein the dummy input and dummy output waveguides surround the active input and active output waveguides respectively and are not interposed between the active input and active output waveguides respectively, such that the presence of the dummy waveguides significantly reduce strain effects within the active input and output waveguides.