US5946336A
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Optical semiconductor apparatus, fabrication method thereof, modulation method therefor, light source apparatus and optical communication system or method using the same
Assignee: Canon Inc
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Filing: 1996-12-26
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Granted: 1999-08-31
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Expires: 2016-12-26
Abstract
Abstract An optical semiconductor apparatus includes a substrate, a first region formed on the substrate, a second region formed on the substrate, and a stimulating unit. The first region includes a first waveguide which extends in a light propagation direction and is constructed so as to permit light waves in two different polarization modes to be propagated in the propagation direction. The first waveguide contains a first active region which is constructed such that a gain for one of the different polarization modes is dominant. The second region includes a second waveguide which extends in the propagation direction, is coupled to the first waveguide and is constructed so as to permit light waves in the different polarization modes to be propagated in the propagation direction. The second waveguide contains a second active region which is constructed such that a gain for the other of the different polarization modes is dominant. At least one of the first and second active regions includes a first active layer, in which a gain for one of the different polarization modes is dominant, and a second active layer, in which a gain for the other of the different polarization modes is dominant. The stimulating unit stimulates the first and second active regions independently from each other.
Inventors
- 👤 Natsuhiko Mizutani
- 👤 Seiichi Miyazawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:15
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/06; H01S5/062; H01S5/0625; B; B82; B82Y; B82Y20/00; H01S2301/00; H01S2301/14; H01S5/06233; H01S5/06236; H01S5/30; H01S5/34; H01S5/3403; H01S5/3404
Claims Analysis
Total Claims: 46
Claim 1
Independent Claim
313 words
An optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein both of said first active region and said second active region respectively include common active layers whose constructions are identical with each other and which are respectively comprised of at least one of said first active layer and said second active layer, and wherein one of said first active region and said second active region only includes said common active layer and the other of said first active region and said second active region includes said common active layer and an additional active layer.
Claim 2
Dependent Claim
313 words
An optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein both of said first active region and said second active region respectively include common active layers whose constructions are identical with each other and which are respectively comprised of at least one of said first active layer and said second active layer, and wherein one of said first active region and said second active region only includes said common active layer and the other of said first active region and said second active region includes said common active layer and an additional active layer.
Claim 3
Dependent Claim
275 words
An optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein one of said first active region and said second active region includes said first active layer and said second active layer formed on said first active layer and the other of said first active region and said second active region includes only said second active layer.
Claim 4
Dependent Claim
275 words
An optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein one of said first active region and said second active region includes said first active layer and said second active layer formed on said first active layer and the other of said first active region and said second active region includes only said second active layer.
Claim 5
Dependent Claim
275 words
An optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein one of said first active region and said second active region includes said first active layer and said second active layer formed on said first active layer and the other of said first active region and said second active region includes only said first active layer.
Claim 6
Dependent Claim
275 words
An optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein one of said first active region and said second active region includes said first active layer and said second active layer formed on said first active layer and the other of said first active region and said second active region includes only said first active layer.
Claim 7
Dependent Claim
33 words
An optical semiconductor apparatus according to any one of claims 1, 2 or 3, wherein said first region and said second region are serially arranged on said substrate along the light propagation direction.
Claim 8
Dependent Claim
30 words
An optical semiconductor apparatus according to any one of claims 1, 2 or 3, further comprising a wavelength selection means for selecting a radiation wavelength of said optical semiconductor apparatus.
Claim 9
Dependent Claim
26 words
An optical semiconductor apparatus according to claim 5, wherein said wavelength selection means comprises a diffraction grating formed along said first waveguide and said second waveguide.
Claim 10
Dependent Claim
20 words
An optical semiconductor apparatus according to claim 6, wherein said optical semiconductor apparatus is constructed as a distributed feedback laser.
Claim 11
Dependent Claim
30 words
An optical semiconductor apparatus according to claim 6, further comprising end facets and an antireflection coating provided on at least one of said end facets of said optical semiconductor apparatus.
Claim 12
Dependent Claim
25 words
An optical semiconductor apparatus according to claim 1, wherein said additional active layer comprises one of said first active layer and said second active layer.
Claim 13
Dependent Claim
24 words
An optical semiconductor apparatus according to claim 1, wherein said additional active layer is placed closer to a p-side than said common active layer.
Claim 14
Dependent Claim
39 words
An optical semiconductor apparatus according to any one of claims 1, 2 or 3, wherein said first active layer comprises a non-strained or compressively strained quantum well layer and said second active layer comprises a tensile-strained quantum well layer.
Claim 15
Dependent Claim
35 words
An optical semiconductor apparatus according to claim 11, wherein at least one of said non-strained or compressively-strained quantum well layer and said tensile-strained quantum well layer comprises a plurality of kinds of quantum well layers.
Claim 16
Dependent Claim
55 words
An optical semiconductor apparatus according to claim 11, wherein said first active layer and said second active layer respectively have substantially the same transition energy between a ground level of electrons in a conduction band of said quantum well layer and a ground level of holes in a valence band of said quantum well layer.
Claim 17
Dependent Claim
32 words
An optical semiconductor apparatus according to claim 2, wherein said second active layers respectively contained in said first active region and said second active region are identical with each other in construction.
Claim 18
Dependent Claim
24 words
An optical semiconductor apparatus according to claim 2, wherein said first active layer is placed closer to a p-side than said second active layer.
Claim 19
Dependent Claim
32 words
An optical semiconductor apparatus according to claim 13, wherein said first active layers respectively contained in said first active region and said second active region are identical with each other in construction.
Claim 20
Dependent Claim
24 words
An optical semiconductor apparatus according to claim 13, wherein said second active layer is placed closer to a p-side than said first active layer.
Claim 21
Dependent Claim
33 words
An optical semiconductor apparatus according to any one of claims 1, 2 or 3, further comprising an etching stopper layer for stopping an etching process performed during fabrication of said optical semiconductor apparatus.
Claim 22
Dependent Claim
27 words
An optical semiconductor apparatus according to claim 18, wherein said etching stopper layer is formed in one of said first active region and said second active region.
Claim 23
Dependent Claim
26 words
An optical semiconductor apparatus according to claim 18, wherein said etching stopper layer is formed immediately under said first active region and said second active region.
Claim 24
Dependent Claim
41 words
An optical semiconductor apparatus according to claim 18, wherein said substrate, said first region and said second region are formed with materials of In x Ga 1-x As y P 1-y series, and said etching stopper layer is made of InP.
Claim 25
Dependent Claim
36 words
An optical semiconductor apparatus according to any one of claims 1, 2 or 3, further comprising a boundary surface improving layer for improving a boundary condition between said first active layer and said second active layer.
Claim 26
Dependent Claim
42 words
An optical semiconductor apparatus according to claim 22, wherein said substrate, said first region and said second region are formed with materials of In x Ga 1-x As y P 1-y series, and said boundary surface improving layer is made of InP.
Claim 27
Dependent Claim
33 words
An optical semiconductor apparatus according to any one of claims 1, 2 or 3, wherein at least one of said first active layer and said second active layer is doped with an impurity.
Claim 28
Dependent Claim
44 words
An optical semiconductor apparatus according to any one of claims 1, 2 or 3, further comprising a barrier layer formed between said first active layer and said second active layer for separating said first active layer and said second active layer from each other.
Claim 29
Dependent Claim
27 words
An optical semiconductor apparatus according to any one of claims 1, 2 or 3, wherein said optical semiconductor apparatus is constructed as an oscillation polarization-mode switchable laser.
Claim 30
Dependent Claim
28 words
An optical semiconductor apparatus according to any one of claims 1, 2 or 3, wherein said optical semiconductor apparatus is constructed as a polarization-mode insensitive semiconductor optical amplifier.
Claim 31
Independent Claim
447 words
A method for driving an optical semiconductor apparatus which includes a substrate; a first region formed on the substrate, the first region including a first waveguide which extends in a light propagation direction and is constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, the first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant; a second region formed on the substrate, the second region including a second waveguide which extends in the light propagation direction, is coupled to said first waveguide and is constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, the second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant, at least one of the first active region and the second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating the first active region and the second active region independently from each other, wherein both of the first active region and the second active region respectively include common active layers whose constructions are identical with each other and which are respectively comprised of at least one of the first active layer and the second active layer, and wherein one of the first active region and the second active region only includes the common active layer and the other of the first active region and said second active region includes the common active layer and an additional active layer, said driving method comprising the steps of: establishing a bias state, in which a round-trip gain for one of the two different polarization modes competes with a round-trip gain for the other of the two different polarization modes, by controlling amounts of currents respectively injected into the first active region and the second active region by the stimulating means; establishing a modulation bias point, in which light in one of the two different polarization modes is oscillated, by slightly increasing the amount of the current injected into one of the first active region and the second active region; and switching the polarization mode of the oscillated light between the two different polarization modes by injecting a signal of a minute modulation current into at least one of the first active region and the second active region.
Claim 32
Independent Claim
447 words
A method for driving an optical semiconductor apparatus which includes a substrate; a first region formed on the substrate, the first region including a first waveguide which extends in a light propagation direction and is constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, the first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant; a second region formed on the substrate, the second region including a second waveguide which extends in the light propagation direction, is coupled to said first waveguide and is constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, the second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant, at least one of the first active region and the second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating the first active region and the second active region independently from each other, wherein both of the first active region and the second active region respectively include common active layers whose constructions are identical with each other and which are respectively comprised of at least one of the first active layer and the second active layer, and wherein one of the first active region and the second active region only includes the common active layer and the other of the first active region and said second active region includes the common active layer and an additional active layer, said driving method comprising the steps of: establishing a bias state, in which a round-trip gain for one of the two different polarization modes competes with a round-trip gain for the other of the two different polarization modes, by controlling amounts of currents respectively injected into the first active region and the second active region by the stimulating means; establishing a modulation bias point, in which light in one of the two different polarization modes is oscillated, by slightly increasing the amount of the current injected into one of the first active region and the second active region; and switching the polarization mode of the oscillated light between the two different polarization modes by injecting a signal of a minute modulation current into at least one of the first active region and the second active region.
Claim 33
Dependent Claim
389 words
An optical communication method for transmitting a signal from a transmitter to a receiver through an optical transmission line, the transmitter including an optical semiconductor apparatus which includes a substrate; a first region formed on the substrate, the first region including a first waveguide which extends in a light propagation direction and is constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, the first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant; a second region formed on the substrate, the second region including a second waveguide which extends in the light propagation direction, is coupled to said first waveguide and is constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, the second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant, at least one of the first active region and the second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating the first active region and the second active region independently from each other, wherein both of the first active region and the second active region respectively include common active layers whose constructions are identical with each other and which are respectively comprised of at least one of the first active layer and the second active layer, and wherein one of the first active region and the second active region only includes the common active layer and the other of the first active region and said second active region includes the common active layer and an additional active layer, said method comprising the steps of: modulating the polarization mode of light output from the optical semiconductor apparatus between two different polarization modes by controlling current injected into the optical semiconductor apparatus; selecting only the light output in one of the two different polarization modes to create an amplitude-modulated signal; and transmitting the amplitude-modulated signal through the optical transmission line.
Claim 34
Dependent Claim
389 words
An optical communication method for transmitting a signal from a transmitter to a receiver through an optical transmission line, the transmitter including an optical semiconductor apparatus which includes a substrate; a first region formed on the substrate, the first region including a first waveguide which extends in a light propagation direction and is constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, the first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant; a second region formed on the substrate, the second region including a second waveguide which extends in the light propagation direction, is coupled to said first waveguide and is constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, the second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant, at least one of the first active region and the second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating the first active region and the second active region independently from each other, wherein both of the first active region and the second active region respectively include common active layers whose constructions are identical with each other and which are respectively comprised of at least one of the first active layer and the second active layer, and wherein one of the first active region and the second active region only includes the common active layer and the other of the first active region and said second active region includes the common active layer and an additional active layer, said method comprising the steps of: modulating the polarization mode of light output from the optical semiconductor apparatus between two different polarization modes by controlling current injected into the optical semiconductor apparatus; selecting only the light output in one of the two different polarization modes to create an amplitude-modulated signal; and transmitting the amplitude-modulated signal through the optical transmission line.
Claim 35
Dependent Claim
376 words
An optical communication system for transmitting a signal from a transmitter to a receiver through an optical transmission line, said system comprising: an optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein both of said first active region and said second active region respectively include common active layers whose constructions are identical with each other and which are respectively comprised of at least one of said first active layer and said second active layer, and wherein one of said first active region and said second active region only includes said common active layer and the other of said first active region and said second active region includes said common active layer and an additional active layer; and means for selecting only the light output in one of the two different polarization modes so as to create an amplitude-modulated signal, the amplitude-modulated signal being the signal transmitted from the transmitter to the receiver through the optical transmission line.
Claim 36
Dependent Claim
376 words
An optical communication system for transmitting a signal from a transmitter to a receiver through an optical transmission line, said system comprising: an optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein both of said first active region and said second active region respectively include common active layers whose constructions are identical with each other and which are respectively comprised of at least one of said first active layer and said second active layer, and wherein one of said first active region and said second active region only includes said common active layer and the other of said first active region and said second active region includes said common active layer and an additional active layer; and means for selecting only the light output in one of the two different polarization modes so as to create an amplitude-modulated signal, the amplitude-modulated signal being the signal transmitted from the transmitter to the receiver through the optical transmission line.
Claim 37
Dependent Claim
334 words
A light source apparatus comprising: an optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein both of said first active region and said second active region respectively include common active layers whose constructions are identical with each other and which are respectively comprised of at least one of said first active layer and said second active layer, and wherein one of said first active region and said second active region only includes said common active layer and the other of said first active region and said second active region includes said common active layer and an additional active layer; and means for selecting only the light output in one of the two different polarization modes.
Claim 38
Dependent Claim
334 words
A light source apparatus comprising: an optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein both of said first active region and said second active region respectively include common active layers whose constructions are identical with each other and which are respectively comprised of at least one of said first active layer and said second active layer, and wherein one of said first active region and said second active region only includes said common active layer and the other of said first active region and said second active region includes said common active layer and an additional active layer; and means for selecting only the light output in one of the two different polarization modes.
Claim 39
Independent Claim
409 words
A method for driving an optical semiconductor apparatus which includes a substrate; a first region formed on the substrate, the first region including a first waveguide which extends in a light propagation direction and is constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, the first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant; a second region formed on the substrate, the second region including a second waveguide which extends in the light propagation direction, is coupled to said first waveguide and is constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, the second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant, at least one of the first active region and the second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating the first active region and the second active region independently from each other, wherein one of the first active region and the second active region includes the first active layer and the second active layer formed on the first active layer and the other of the first active region and the second active region includes only the second active layer, said driving method comprising the steps of: establishing a bias state, in which a round-trip gain for one of the two different polarization modes competes with a round-trip gain for the other of the two different polarization modes, by controlling amounts of currents respectively injected into the first active region and the second active region by the stimulating means; establishing a modulation bias point, in which light in one of the two different polarization modes is oscillated, by slightly increasing the amount of the current injected into one of the first active region and the second active region; and switching the polarization mode of the oscillated light between the two different polarization modes by injecting a signal of a minute modulation current into at least one of the first active region and the second active region.
Claim 40
Independent Claim
409 words
A method for driving an optical semiconductor apparatus which includes a substrate; a first region formed on the substrate, the first region including a first waveguide which extends in a light propagation direction and is constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, the first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant; a second region formed on the substrate, the second region including a second waveguide which extends in the light propagation direction, is coupled to said first waveguide and is constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, the second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant, at least one of the first active region and the second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating the first active region and the second active region independently from each other, wherein one of the first active region and the second active region includes the first active layer and the second active layer formed on the first active layer and the other of the first active region and the second active region includes only the second active layer, said driving method comprising the steps of: establishing a bias state, in which a round-trip gain for one of the two different polarization modes competes with a round-trip gain for the other of the two different polarization modes, by controlling amounts of currents respectively injected into the first active region and the second active region by the stimulating means; establishing a modulation bias point, in which light in one of the two different polarization modes is oscillated, by slightly increasing the amount of the current injected into one of the first active region and the second active region; and switching the polarization mode of the oscillated light between the two different polarization modes by injecting a signal of a minute modulation current into at least one of the first active region and the second active region.
Claim 41
Dependent Claim
351 words
An optical communication method for transmitting a signal from a transmitter to a receiver through an optical transmission line, the transmitter including an optical semiconductor apparatus which includes a substrate; a first region formed on the substrate, the first region including a first waveguide which extends in a light propagation direction and is constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, the first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant; a second region formed on the substrate, the second region including a second waveguide which extends in the light propagation direction, is coupled to said first waveguide and is constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, the second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant, at least one of the first active region and the second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating the first active region and the second active region independently from each other, wherein one of the first active region and the second active region includes the first active layer and the second active layer formed on the first active layer and the other of the first active region and the second active region includes only the second active layer, said method comprising the steps of: modulating the polarization mode of light output from the optical semiconductor apparatus between two different polarization modes by controlling current injected into the optical semiconductor apparatus; selecting only the light output in one of the two different polarization modes to create an amplitude-modulated signal; and transmitting the amplitude-modulated signal through the optical transmission line.
Claim 42
Dependent Claim
351 words
An optical communication method for transmitting a signal from a transmitter to a receiver through an optical transmission line, the transmitter including an optical semiconductor apparatus which includes a substrate; a first region formed on the substrate, the first region including a first waveguide which extends in a light propagation direction and is constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, the first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant; a second region formed on the substrate, the second region including a second waveguide which extends in the light propagation direction, is coupled to said first waveguide and is constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, the second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant, at least one of the first active region and the second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating the first active region and the second active region independently from each other, wherein one of the first active region and the second active region includes the first active layer and the second active layer formed on the first active layer and the other of the first active region and the second active region includes only the second active layer, said method comprising the steps of: modulating the polarization mode of light output from the optical semiconductor apparatus between two different polarization modes by controlling current injected into the optical semiconductor apparatus; selecting only the light output in one of the two different polarization modes to create an amplitude-modulated signal; and transmitting the amplitude-modulated signal through the optical transmission line.
Claim 43
Dependent Claim
338 words
An optical communication system for transmitting a signal from a transmitter to a receiver through an optical transmission line, said system comprising: an optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein one of said first active region and said second active region includes said first active layer and said second active layer formed on said first active layer and the other of said first active region and said second active region includes only said second active layer; and means for selecting only the light output in one of the two different polarization modes so as to create an amplitude-modulated signal, the amplitude-modulated signal being the signal transmitted from the transmitter to the receiver through the optical transmission line.
Claim 44
Dependent Claim
338 words
An optical communication system for transmitting a signal from a transmitter to a receiver through an optical transmission line, said system comprising: an optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein one of said first active region and said second active region includes said first active layer and said second active layer formed on said first active layer and the other of said first active region and said second active region includes only said second active layer; and means for selecting only the light output in one of the two different polarization modes so as to create an amplitude-modulated signal, the amplitude-modulated signal being the signal transmitted from the transmitter to the receiver through the optical transmission line.
Claim 45
Dependent Claim
296 words
A light source apparatus comprising: an optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein one of said first active region and said second active region includes said first active layer and said second active layer formed on said first active layer and the other of said first active region and said second active region includes only said second active layer; and means for selecting only the light output in one of the two different polarization modes.
Claim 46
Dependent Claim
296 words
A light source apparatus comprising: an optical semiconductor apparatus comprising: a substrate; a first region formed on said substrate, said first region including a first waveguide which extends in a light propagation direction, said first region being constructed so as to permit light waves in two different polarization modes to be propagated in the light propagation direction, said first waveguide containing a first active region which is constructed such that a gain for one of the two different polarization modes is dominant therein; a second region formed on said substrate, said second region including a second waveguide which extends in the light propagation direction, said second region being coupled to said first waveguide and being constructed so as to permit light waves in the two different polarization modes to be propagated in the light propagation direction, said second waveguide containing a second active region which is constructed such that a gain for the other of the two different polarization modes is dominant therein, at least one of said first active region and said second active region including a first active layer, in which a gain for one of the two different polarization modes is dominant, and a second active layer, in which a gain for the other of the two different polarization modes is dominant; and stimulating means for stimulating said first active region and said second active region independently from each other, wherein one of said first active region and said second active region includes said first active layer and said second active layer formed on said first active layer and the other of said first active region and said second active region includes only said second active layer; and means for selecting only the light output in one of the two different polarization modes.
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