Appeal 2007-0953
Application 10/607,466
STATEMENT OF THE CASE
Appellants invented a wavelength division multiplexer/demultiplexer
used in a planar lightwave circuit for multiplexing and demultiplexing
optical signals. Specifically, the invention comprises an input waveguide for
inputting a multiplexed optical signal to an arrayed waveguide grating
(AWG), and output waveguides for outputting single-channel optical signals
demultiplexed by the AWG. The input waveguide comprises two sub-
waveguides: a first sub-waveguide with a parabolic horn shape, and a second
sub-waveguide with a progressively decreasing width. Such a structure not
only increases bandwidth via mode coupling, but also reduces side-lobe
generation by the higher mode optical signal. Both the input waveguide and
the output waveguides are disposed on both sides of the substrate centering
on the AWG thereby providing a bi-directional multiplexing/demultiplexing
capability.1 Claim 10 is illustrative:
10. A wavelength division multiplexer/demultiplexer for use in a
planar lightwave circuit (PLC) having an arrayed waveguide grating
including a plurality of optical waveguides, an input waveguide for inputting
a multiplexed optical signal to the grating, and output waveguides for
outputting single-channel optical signals demultiplexed by the grating, the
wavelength division multiplexer/demultiplexer comprising:
an input waveguide having,
a first sub-waveguide, whose width gradually increases in a
progressing direction of the optical signal such that, starting at an input of
the sub-waveguide and with the gradual increase, tapering of the sub-
waveguide is directed inwardly in a concave manner; and
1 See generally Specification page 5, line 1 through page 6, line 6; page 9,
lines 2-6; page 10, line 15 through page 11, line 14; page 13, line 12 through
page 14, line 10.
2
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