Semiconductor laser array, semiconductor laser element, semiconductor laser module, and wavelength-variable laser assembly

A semiconductor optical element comprising:

• an optical coupler configured to multiplex laser lights outputted from a plurality of semiconductor lasers;
• and
• a semiconductor optical amplifier configured to amplify a light outputted from the optical coupler, wherein the semiconductor optical amplifier includes:
• an active layer including a multi-quantum well structure including a plurality of well layers and a plurality of barrier layers laminated alternately, wherein the active layer is doped with an n-type impurity, wherein a doping concentration of the n-type impurity is 1×1017 cm−3 or more and 1.2×1018 cm−3 or less, and wherein the active layer is surrounded by indium phosphate (InP);
• and
• a n-side separate confinement heterostructure layer and a p-side separate confinement heterostructure layer configured to sandwich the active layer therebetween in a thickness direction, wherein band gap energies of the n-side separate confinement heterostructure layer and the p-side separate confinement heterostructure layer are greater than band gap energies of the plurality of barrier layers of the active layer and are asymmetric across the active layer, and wherein the p-side separate confinement heterostructure layer is thicker than the n-side separate confinement heterostructure layer,
• wherein at least one of the n-side separate confinement heterostructure layer and the p-side separate confinement heterostructure layer includes a plurality of layers, and a composition wavelength of at least one layer of the plurality of layers differs from a composition wavelength of at least another layer of the plurality of layers,
• wherein a full width at half maximum of an illumination spectrum of the semiconductor optical amplifier is 80.1 meV or higher and 95.9 meV or lower,
• wherein the semiconductor optical amplifier is driven without causing laser oscillation,
• wherein the semiconductor optical element is configured to switch an operating semiconductor laser among the plurality of the semiconductor lasers, and to vary a wavelength of the laser light outputted from the semiconductor laser based on change in a temperature of the semiconductor laser,
• wherein the n-side separate confinement heterostructure layer includes a first multi-stepped configuration of a first bulk material having a first plurality of composition wavelengths, and the p-side separate confinement heterostructure layer includes a second multi-stepped configuration of a second bulk material having a second plurality of composition wavelengths that are different from the first plurality of composition wavelengths, and
• wherein the first multi-stepped configuration includes two or three steps of a separate confinement heterostructure, and the second multi-stepped configuration includes six or seven steps of a separate confinement heterostructure.

A semiconductor laser module comprising:

• a semiconductor optical element including:
• an optical coupler configured to multiplex laser lights outputted from a plurality of semiconductor lasers;
• and
• a semiconductor optical amplifier configured to amplify a light outputted from the optical coupler, wherein the semiconductor optical amplifier includes:
• an active layer including a multi-quantum well structure including a plurality of well layers and a plurality of barrier layers laminated alternately, wherein the active layer is doped with an n-type impurity, wherein a doping concentration of the n-type impurity is 1×1017 cm−3 or more and 1.2×1018 cm−3 or less, and wherein the active layer is surrounded by indium phosphate (InP);
• and
• a n-side separate confinement heterostructure layer and a p-side separate confinement heterostructure layer configured to sandwich the active layer therebetween in a thickness direction, wherein band gap energies of the n-side separate confinement heterostructure layer and the p-side separate confinement heterostructure layer are greater than band gap energies of the plurality of barrier layers of the active layer and are asymmetric across the active layer, and wherein the p-side separate confinement heterostructure layer is thicker than the n-side separate confinement heterostructure layer,
• wherein at least one of the n-side separate confinement heterostructure layer and the p-side separate confinement heterostructure layer includes a plurality of layers, and a composition wavelength of at least one layer of the plurality of layers differs from a composition wavelength of at least another layer of the plurality of layers,
• wherein a full width at half maximum of an illumination spectrum of the semiconductor optical amplifier is 80.1 meV or higher and 95.9 meV or lower,
• wherein the semiconductor optical amplifier is driven without causing laser oscillation, and
• wherein the semiconductor optical element is configured to switch an operating semiconductor laser among the plurality of the semiconductor lasers, and to vary a wavelength of the laser light outputted from the semiconductor laser based on change in a temperature of the semiconductor laser;
• an optical fiber configured to emit a laser light outputted by the semiconductor optical element to outside;
• an optical component configured to couple the laser light outputted by the semiconductor optical element to the optical fiber,
• wherein the n-side separate confinement heterostructure laver includes a first multi-stepped configuration of a first bulk material having a first plurality of composition wavelengths, and the p-side separate confinement heterostructure layer includes a second multi-stepped configuration of a second bulk material having a second plurality of composition wavelengths that are different from the first plurality of composition wavelengths, and
• wherein the first multi-stepped configuration includes two or three steps of a separate confinement heterostructure, and the second multi-stepped configuration includes six or seven steps of a separate confinement heterostructure.

A wavelength-tunable laser assembly comprising:

• a semiconductor laser module;
• and
• an electronic substrate configured to drive and control the semiconductor laser module mounted on the electronic substrate,
• wherein the semiconductor laser module includes:
• a semiconductor optical element including:
• an optical coupler configured to multiplex laser lights outputted from a plurality of semiconductor lasers;
• and
• a semiconductor optical amplifier configured to amplify a light outputted from the optical coupler, wherein the semiconductor optical amplifier includes:
• an active layer including a multi-quantum well structure including a plurality of well layers and a plurality of barrier layers laminated alternately, wherein the active layer is doped with an n-type impurity, wherein a doping concentration of the n-type impurity is 1×1017 cm−3 or more and 1.2×1018 cm−3 or less, and wherein the active layer is surrounded by InP;
• and
• a n-side separate confinement heterostructure layer and a p-side separate confinement heterostructure layer configured to sandwich the active layer therebetween in a thickness direction, wherein band gap energies of the n-side separate confinement heterostructure layer and the p-side separate confinement heterostructure layer are greater than band gap energies of the plurality of barrier layers of the active layer and are asymmetric across the active layer, and wherein the p-side separate confinement heterostructure layer is thicker than the n-side separate confinement heterostructure layer,
• wherein at least one of the n-side separate confinement heterostructure layer and the p-side separate confinement heterostructure layer includes a plurality of layers, and a composition wavelength of at least one layer of the plurality of layers differs from a composition wavelength of at least another layer of the plurality of layers,
• wherein a full width at half maximum of an illumination spectrum of the semiconductor optical amplifier is 80.1 meV or higher and 95.9 meV or lower,
• wherein the semiconductor optical amplifier is driven without causing laser oscillation, and
• wherein the semiconductor optical element is configured to switch an operating semiconductor laser among the plurality of the semiconductor lasers, and to vary a wavelength of the laser light outputted from the semiconductor laser based on change in a temperature of the semiconductor laser;
• an optical fiber configured to emit a laser light outputted by the semiconductor optical element to outside;
• and
• an optical component configured to couple the laser light outputted by the semiconductor optical element to the optical fiber,
• wherein the n-side separate confinement heterostructure laver includes a first multi-stepped configuration of a first bulk material having a first plurality of composition wavelengths, and the p-side separate confinement heterostructure laver includes a second multi-stepped configuration of a second bulk material having a second plurality of composition wavelengths that are different from the first plurality of composition wavelengths, and
• wherein the first multi-stepped configuration includes two or three steps of a separate confinement heterostructure, and the second multi-stepped configuration includes six or seven steps of a separate confinement heterostructure.