| CPC G02F 1/212 (2021.01) [G02F 1/225 (2013.01); G02B 6/125 (2013.01)] | 15 Claims |
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1. A Mach-Zehnder interferometric optical modulator comprising:
first and second lower clad layers stacked on a substrate;
a core layer on the first and second lower clad layers;
an upper clad layer on the core layer;
a waveguide on the upper clad layer; and
electrodes on the waveguide,
wherein the waveguide comprises:
an input waveguide;
an output waveguide spaced apart from the input waveguide;
a waveguide divider between the output waveguide and the input waveguide;
a waveguide combiner between the waveguide divider and the output waveguide; and
branch waveguides between the waveguide combiner and the waveguide divider,
wherein each of the branch waveguides comprises:
first and second connection regions connected to the waveguide combiner and the waveguide divider, respectively; and
a phase shift region provided between the first and second connection regions and having a cross-section of a reverse mesa structure that has an upper width that is the same as widths of the first and second connection regions and a lower width that is smaller than the widths of the first and second connection regions.
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