Patent ID: 6374013
Filing Date: 2002-04-16
Classification: G02B

Abstract:
An arrayed waveguide device, which device includes an arrayed waveguide grating having first and second ends optically coupled respectively by first and second radiative star couplers with an input/output waveguide and with an output/input waveguide, wherein said input/output waveguide terminates non-adiabatically in a multimode interference section abutting the first radiative star coupler, which multimode interference section is dimensioned to guide at least the zero, second and fourth order modes, wherein the multimode interference section is dimensioned such that, in respect of light of a wavelength transmitted through the device via said input/output and output/input waveguides and that is launched into the multimode interference section from being guided by the input/output waveguide, at least three modes are concurrently excited in the multimode interference section, wherein the arrayed waveguide grating comprises a set of optical waveguides in side-by-side array defining a set of optical paths extending from said first end to said second end, each path being of incrementally greater optical path length from a shortest value at one side of the array to a longest value at the other, thereby defining a set of optical path length increments by which the optical path length of each optical path of the array, other than that of the shortest optical path of the array, is longer than that of the next shorter optical path of the array, and wherein the optical paths of the array have a non-uniform distribution of values of optical attenuation and of optical path length increment providing the arrayed waveguide device with a set of wavelength passbands each exhibiting a chromatic dispersion of significantly reduced magnitude in comparison with that exhibited by the corresponding wavelength passband of an equivalent arrayed waveguide device differing only in that the optical attenuations and optical path length increments of the optical paths of its array are all equal.