Bipolar voltage controlled optical switch using intersecting waveguides
AssigneeFujitsu Limited
InventorsMinoru Seino, Hirochika Nakajima, Ippei Sawaki, Hidehiro Mishiro
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Abstract
An optical switch comprising: an electrode-optic crystal substrate (1, 1'); a central waveguide (21); a pair of input waveguides (22, 23), and a pair of output waveguides (24, 25). A refractive-index-changed region (R') is provided symmetrically within some part of the central waveguide. Switching from the straight-through state to the branching state or vice versa is carried out by introducing a change in the refractive index of the index-changed region.
Claims15
A bipolar 2.times.2 type optical switch for single mode light comprising:
- an electro-optic crystal substrate;
- a central waveguide positioned in said substrate, having a center, two ends and a width that is greater at said ends than at said center;
- a pair of input waveguides positioned in said substrate, connected to said central waveguide at one of said two ends, and having an intersecting angle of less than 2.degree.;
- a pair of output waveguides positioned in said substrate, connected to said central waveguide at the other of said two ends so as to be symmetrical with said pair of input waveguides about said central waveguide, and having an intersecting angle of less than 2.degree.;
- a refractive-index-changed region positioned in said central waveguide and having a narrower width than said width of said central waveguide, and being formed symmetrically with respect to the center of said central waveguide;
- and
- a means for introducing a change in the refractive index of the refractive-index-changed region.
A bipolar-type 2.times.2 type optical switch for single-mode light comprising:
- an electro-optic crystal substrate comprising a LiNbO.sub.3 Z plate;
- two waveguides intersecting at an angle of less than 2.degree. positioned in said substrate, said waveguides having a higher refractive index than said substrate and an intersecting portion of said two waveguides having a width being smaller at a center portion than at end portions thereof;
- a refractive-index-changed region in said intersecting portion having a narrower width than said width of said intersecting portion, and being positioned symmetrically with respect to said center of said intersecting portion;
- and
- refractive index change means for introducing a change in the refractive index of said refractive-index-changed region;
- said refractive index change means comprising:
- a drive electrode formed on said refractive-index-changed region of said LiNbO.sub.3 Z plate;
- a ground electrode positioned on said LiNbO.sub.3 Z plate and displaced from said refractive-index-changed region;
- and
- a means for applying a positive voltage or a negative voltage to said drive electrode.
A bipolar 2.times.2 type optical switch for single-mode light comprising:
- an electro-optic crystal substrate comprising a LiNbO.sub.3 X or Y plate;
- two waveguides intersecting at an angle of less than 2.degree. and positioned in said substrate, said two waveguides having a higher refractive index than said substrate and an intersecting portion of said two waveguides having a width being smaller at a center portion than at end portions of the intersecting portion;
- a refractive-index-changed region in said intersecting portion having a narrower width than said width of said intersecting portion, and being positioned symmetrically with respect to said center of said intersecting portion;
- refractive change means for introducing a change in the refractive index of said refractive-index-changed region, said refractive change means including:
- two electrodes positioned on said LiNbO.sub.3 X or Y plate and
- sandwiching said index-changed-region, and
- means for applying a voltage to said electrodes.
Dependencies are inferred from the claim text.