The present disclosure relates to a glass having a refractive index of at least 1.7 as well as the use of the glass as a cladding glass of a solid-state laser. The disclosure also relates to a laser component comprising a core of doped sapphire and a cladding glass being placed on said core. The cladding glass is arranged on said core such that light exiting from the core due to parasitic laser activity can enter the cladding glass and can be absorbed there. Thus, a laser component with improved efficiency is obtained. The present disclosure also relates to a method for producing the laser component.

A nitride semiconductor device includes a GaN substrate in which an angle between a principal surface and an m-plane of GaN is 5 or more and +5 or less, a first intermediate layer disposed on the principal surface of the substrate and made of Al.sub.zGa.sub.(1z)N, 0z1, and a second intermediate layer disposed on a principal surface of the first intermediate layer, having an Al content different from that of the first intermediate layer, and made of Al.sub.x1In.sub.y1Ga.sub.(1x1y1)N, 0x11, 0y11. A quantum cascade laser includes the nitride semiconductor device.

A method of producing an ultraviolet laser diode with a low oscillation threshold current density includes stacking a first cladding layer, a light-emitting layer, and a second cladding layer on a substrate in this order to form a nitride semiconductor laminate (step S101), etching at least a portion of the nitride semiconductor laminate to form a mesa structure and setting the ratio between the length of the resonator end faces and the length of the side surfaces of the mesa structure in plan view between 1:5 and 1:500 (step S102), disposing first conductive material on a portion of a first area and applying heat treatment of 400 C. or higher to form a first electrode (step S103), and disposing a second conductive material in an area on the second cladding layer, at a distance of 5 m or more from the side surfaces, to form a second electrode (step S104).

A fiber optic cable including a first end and a second end, a core adapted to receive and transmit an optical signal and a cladding layer surrounding the core is disclosed. The fiber optic cable may include a ratio of an outside diameter of the cladding layer to a diameter of the core that decreases from the first end to the second end while the diameter of the core remains substantially uniform. The fiber optic cable may include a first portion of the cladding layer and a second portion of the cladding layer. A uniform outside diameter of the second portion may be less than a uniform outside diameter of the first portion. The fiber optic cable may further include a third portion of the cladding layer. A uniform outside diameter of the third portion may be less than a uniform outside diameter of the second portion.

In an example, the present invention provides a method for fabricating a light emitting device configured as a Group III-nitride based laser device. The method also includes forming a gallium containing epitaxial material overlying the surface region of a substrate member. The method includes forming a p-type (Al,In,Ga)N waveguiding material overlying the gallium containing epitaxial material under a predetermined process condition. The method includes maintaining the predetermined process condition such that an environment surrounding a growth of the p-type (Al,In,Ga)N waveguide material is substantially a molecular N.sub.2 rich gas environment. The method includes maintaining a temperature ranging from 725 C to 925 C during the formation of the p-type (Al,In,Ga)N waveguide material, although there may be variations. In an example, the predetermined process condition is substantially free from molecular H.sub.2 gas.

A method of producing an ultraviolet laser diode with a low oscillation threshold current density includes stacking a first cladding layer, a light-emitting layer, and a second cladding layer on a substrate in this order to form a nitride semiconductor laminate (step S101), etching at least a portion of the nitride semiconductor laminate to form a mesa structure and setting the ratio between the length of the resonator end faces and the length of the side surfaces of the mesa structure in plan view between 1:5 and 1:500 (step S102), disposing first conductive material on a portion of a first area and applying heat treatment of 400 C. or higher to form a first electrode (step S103), and disposing a second conductive material in an area on the second cladding layer, at a distance of 5 m or more from the side surfaces, to form a second electrode (step S104).

A nitride semiconductor device includes a GaN substrate in which an angle between a principal surface and an m-plane of GaN is 5 or more and +5 or less, a first intermediate layer disposed on the principal surface of the substrate and made of Al.sub.zGa.sub.(1-z)N (0z1), and a second intermediate layer disposed on a principal surface of the first intermediate layer, having an Al content different from that of the first intermediate layer, and made of Al.sub.x1In.sub.y1Ga.sub.(1-x1-y1) (0x11, 0y11). A quantum cascade laser includes the nitride semiconductor device.

In an example, the present invention provides a method for fabricating a light emitting device configured as a Group III-nitride based laser device. The method also includes forming a gallium containing epitaxial material overlying the surface region of a substrate member. The method includes forming a p-type (Al,In,Ga)N waveguiding material overlying the gallium containing epitaxial material under a predetermined process condition. The method includes maintaining the predetermined process condition such that an environment surrounding a growth of the p-type (Al,In,Ga)N waveguide material is substantially a molecular N.sub.2 rich gas environment. The method includes maintaining a temperature ranging from 725 C to 925 C during the formation of the p-type (Al,In,Ga)N waveguide material, although there may be variations. In an example, the predetermined process condition is substantially free from molecular H.sub.2 gas.

A light-emitting device is provided. An active layer is disposed on a substrate and between the first semiconductor layer and the second semiconductor layer. The first aluminum-containing semiconductor layer is disposed between the substrate and the first semiconductor layer, and a first aluminum composition ratio of the first aluminum-containing semiconductor layer is greater than that of the first semiconductor layer. The second aluminum-containing semiconductor layer is disposed between the first aluminum-containing semiconductor layer and the first semiconductor layer, and a second aluminum composition ratio of the second aluminum-containing semiconductor layer is greater than that of the first semiconductor layer. The stack structure is disposed between the first and second aluminum-containing semiconductor layers, and the stack structure includes first, second, and third indium-containing semiconductor layers stacked in sequence. The first, second, and third indium-containing semiconductor layers are made of In.sub.a1Al.sub.b1Ga.sub.1-a1-b1N (0<a1+b1<1), In.sub.a2Al.sub.b2Ga.sub.1-a2-b2N (0<a2+b2<1, and In.sub.a3Al.sub.b3Ga.sub.1-a3-b3N (0<a3+b3<1), respectively, and 0<a3a1<a2.

A semiconductor structure can comprise a plurality of first semiconductor layers comprising wide bandgap semiconductor layers, a narrow bandgap semiconductor layer, and a chirp layer between the plurality of first semiconductor layers and the narrow bandgap semiconductor layer. The plurality of first semiconductor layers can comprise a first short-period superlattice (SPSL). The chirp layer can comprise alternating layers of GaN layers and AlN layers. An average composition of Al/(Al+Ga) of the chirp layer changes throughout the chirp layer.