Patent ID: 6266464
Filing Date: 2001-07-24
Classification: G02B

Abstract:
An arrayed waveguide grating device having an input/output waveguide optically coupled with an output/input waveguide via an optical path that includes,optically in series, first and second arrayed waveguide gratings configured to exhibit matched free spectral ranges to said optical path, each of which arrayed waveguide gratings having first and second ends respectively terminating in first and second radiative star couplers associated with that arrayed waveguide grating,which optical path additionally includes an intermediate waveguide that optically couples the second radiative star coupler of the first arrayed waveguide grating with the first radiative star coupler of the second arrayed waveguide,and which optical path also includes first and second multimode interference waveguide sections respectively terminating in one of the radiative star couplers of the first arrayed waveguide grating and in one of the radiative star couplers of the second arrayed waveguide grating, andwherein the first and second multimode interference waveguide sections support at least the zeroth, second and fourth order modes, and their relative lengths are such that, in respect of light launched into their respective waveguides, they produce, where they terminate in their respective radiative star couplers, field distribution phase fronts possessing substantially complementary curvatures.