| US 7,539,378 B2 | ||
| Optical waveguide device and semiconductor device | ||
| Kazumasa Takabayashi, Kawasaki (Japan); and Ken Morito, Kawasaki (Japan) | ||
| Assigned to Fujitsu Limited, Kawasaki (Japan) | ||
| Filed on Jul. 17, 2007, as Appl. No. 11/826,592. | ||
| Application 11/826592 is a continuation of application No. PCT/JP2005/000699, filed on Jan. 20, 2005. | ||
| Prior Publication US 2007/0258681 A1, Nov. 08, 2007 | ||
| Int. Cl. G02B 6/42 (2006.01); G02B 6/26 (2006.01) | ||
| U.S. Cl. 385—40 [385/39] | 13 Claims |
| 1. An optical waveguide divice, comprising:
a first optical waveguide;
a second optical waveguide formed from a material or in a structure different from that of said first optical waveguide and
connected to said first optical waveguide; and
a 1×1 multimode interference waveguide formed by increasing the widths of said first and second optical waveguides in proximity
of a connection interface between said first and second optical waveguides;
wherein said first optical waveguide is an active waveguide wherein absorption is high when current is not injected but gain
can be generated when current is injected; and
said second optical waveguide is a passive waveguide wherein absorption is low when no voltage is applied or no current is
injected;
said optical waveguide device further comprising:
an active waveguide electrode for injecting current to said active waveguide; and
a passive waveguide electrode for performing current injection or voltage application to said passive waveguide;
said active waveguide electrode being formed also above said 1×1 multimode interference waveguide while said passive waveguide
electrode is not formed above said 1×1 multimode interference waveguide.
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