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US 5,491,768 AGranted
Optical waveguide employing modified gallium arsenide
AssigneeThe Chinese University of Hong Kong
InventorKam T. Chan
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Abstract
In an optical waveguide fabrication process, medium weight, relatively stable ions, such as oxygen ions, are implanted, preferably in a multiple-step, multiple-energy level process, into GaAs, InP or other like III-V materials and heterostructures and then annealed by radiant heat, in order to produce a structure with an elevated index of refraction without restriction on the carrier concentration or resistivity of the stock wafer by the presumed generation of stable crystalline defects in the implanted region. The ions used for implantation should not generate free carriers once implanted.
Claims22
An optical waveguide comprising:
- (a) a substrate of substantially III-V material;
- and
- (b) an ion-implanted region within said substrate produced by MeV ion implantation and rapid thermal annealing, said ion-implanted region exhibiting crystalline defects without additional contribution of carriers from the ions such that a higher refractive index exists than in surrounding regions, said ion-implanted region defining a waveguide path.
An optical waveguide comprising:
- (a) a substrate of substantially III-V material;
- and
- (b) an ion-implanted region within aid substrate produced by MeV ion implantation and rapid thermal annealing, said ion-implanted region exhibiting crystalline defects without additional contribution of carriers from the ions such that a higher refractive index exists than in surrounding regions, said ion-implanted region defining a waveguide path, wherein said ion implantation is by means of multiple implantations, each implantation being performed at a different implantation energy.
An optical waveguide comprising:.
- (a) a substrate of substantially III-V material;
- and
- (b) an ion-implanted region within said substrate produced by MeV ion implantation of an ion dose and rapid thermal annealing, said ion-implanted region exhibiting crystalline defects without additional contribution of carriers from the ions such that a higher refractive index exists than in surrounding regions, said ion-implanted region defining a waveguide path, wherein said implantation is by means of multiple implantations wherein the ion dose of said ion implantation is different for at least two implantations.
An optical coupler for a 1.3 .mu.m wavelength optical signal comprising:
- (a) a substrate of substantially III-V material;
- and
- (b) first and second channel waveguides, said first and second channel waveguides each comprising an ion-implanted region within said substrate produced by MeV ion implantation and rapid thermal annealing, said ion-implanted region exhibiting crystalline defects without additional contribution of carriers from the ions such that a higher refractive index exists than in surrounding regions, said ion-implanted region defining a waveguide path, said first channel waveguide having a least one segment spaced in parallel with a corresponding one segment of said second channel waveguide at 6 .mu.m apart (.+-.0.5 .mu.m) and each said first and second channel waveguide having a width of 6 .mu.m (.+-.0.5 .mu.m).
An optical modulator comprising:
- (a) a substrate of substantially III-V material;
- and
- (b) first and second channel waveguides, said first and second channel waveguides each comprising an ion-implanted region within said substrate produced by MeV ion implantation and rapid thermal annealing, said ion-implanted region exhibiting crystalline defects without additional contribution of carriers from the ions such that a higher refractive index exists than in surrounding regions, said first and second channel waveguides being spaced apart sufficiently at an electrode region so as not to interact optically, said first and second channel waveguides being joined in a first common waveguide at an input prior to the electrode region and at a second common waveguide at an output past the electrode region;
- and
- (c) electrical contacts on the surface of said first and second channel waveguides in the electrode region for introducing a modulating voltage and thus controlling the optical modulation of light travelling in the first and second channel waveguides by means of electro-optic effect.
2 more elements
A method for fabricating an optical waveguide comprising:
- (a) providing a substrate of substantially III-V material;
- and
- (b) implanting a dose of ions within said substrate by MeV ion implantation without additional contribution of carriers to the substrate from the ions;
- and
- (c) annealing said substrate so implanted by rapid thermal annealing, such that said ion-implanted region exhibits crystalline defects such that a higher refractive index exists than in surrounding regions, said ion-implanted region defining a waveguide path, wherein said ion implanting step comprises multiple implantations, each at a different implantation energy.
2 more elements
A method for fabricating an optical waveguide comprising:
- (a) providing a substrate of substantially III-V material;
- and
- (b) implanting a dose of ions within said substrate by MeV ion implantation without additional contribution of carriers to the substrate from the ions;
- and
- (c) annealing said substrate so implanted by rapid thermal annealing, such that said ion-implanted region exhibits crystalline defects such that a higher refractive index exists than in surrounding regions, said ion-implanted region defining a waveguide path, wherein said ion implanting step comprises multiple implantations, the ion dose of at least two implantations being different from each other.
2 more elements
A method for fabricating an optical waveguide comprising:
- (a) providing a substrate of substantially III-V material;
- and
- (b) implanting a dose of ions within said substrate by MeV ion implantation without additional contribution of carriers to the substrate from the ions;
- and
- (c) annealing said substrate so implanted by rapid thermal annealing, such that said ion-implanted region exhibits crystalline defects such that a higher refractive index exists than in surrounding regions, said ion-implanted region defining a waveguide path.
2 more elements
A method for fabricating an optical waveguide comprising:
- (a) providing a substrate of substantially III-V material;
- and
- (b) implanting a dose of ions within said substrate by MeV ion implantation without additional contribution of carriers to the substrate from the ions;
- and
- (c) annealing said substrate so implanted by rapid thermal annealing, such that said ion-implanted region exhibits crystalline defects such that a higher refractive index exists than in surrounding regions, said ion-implanted region defining a waveguide path,
- said ion implanting step comprising:
- implanting oxygen ions with energies and doses of the following magnitudes in the following order:
- 1) 3 MeV and 1.times.10.sup.15 cm.sup.-2 (the initial deep implantation);
- 2) 1.5 MeV and 1.times.10.sup.15 cm.sup.-2 (half-energy-level implantation);
- 3) 0.6 MeV and 1.times.10.sup.15 cm.sup.-2 ;
- (one-fifth-energy-level implantation);
- 4) 190 keV and 1.5.times.10.sup.15 cm.sup.-2 (first trimming implantation);
- and
- 5) 100 keV and 1.5.times.10.sup.15 cm.sup.-2 (final trimming implantation).
11 more elements
Dependencies are inferred from the claim text.