Patent ID: 6823096
Filing Date: 2004-11-23
Classification: G02B,H04Q

Abstract:
A broadband optical switching apparatus comprisingan imaging arrangement including a first and second broadband couplers having only three imaging waveguide arms connected therebetween; the first coupler including at least one input connected as an input waveguide of the switching apparatus for receiving a broadband optical signal and three outputs connected to the three imaging arms; the second coupler is a star coupler consisting of a first and second radial array separated by a slab waveguide, the three imaging arms being connected to three central waveguides of the first radial array, and two central waveguides of the second radial array being connected to a first and a second output waveguides of the switching apparatus; the three imaging arms including a top, a central, and a bottom imaging arm; at least two of the three imaging arms including wavelength adjusters to control optical path lengths through the three arms, said adjusters adjusted to produce equal optical path lengths from the input waveguide to the first output waveguide thereby maximizing broadband optical signal power transfer from the input waveguide to the first output waveguide; the spacing between the two central waveguides of the second radial array being selected so as to minimize power transfer to the second output waveguide; and wherein the power transfer to the top, central, and bottom imaging arms is controlled so that the difference between the combined power transferred to the top and bottom imaging arm and the power transferred to the central imaging arm is controlled to have a ratio close to one so that the crosstalk at a center wavelength of the broadband optical signal does not exceed a predetermined value.