Semiconductor laser device with a current non-injection region near a resonator end face, and fabrication method thereof

A semiconductor laser device comprising:

• two opposite resonator end faces where at least a first conduction type first cladding layer, a first conduction type or i-type first optical waveguide layer, an i-type Inx2Ga1−x2As1−y2Py2 first barrier layer having tensile strain (where x2/0.49≦y2≦0.3+(x2/0.49), and 0.8≦y2≦1.0), an i-type Inx3Ga1−x3As1−y3Py quantum well active layer (where 0.3≦x3≦0.2 and y3=x3/0.49), an i-type Inx2Ga1−x2As1−y2Py2 second barrier layer having tensile strain (where x2/0.49≦y2≦0.3+(x2/0.49), and 0.8≦y2≦1.0), a second conduction type or i-type second optical waveguide layer, a second conduction type second cladding layer, a second conduction type contact layer, are stacked on a first conduction type GaAs substrate in the recited order;
• wherein said first cladding layer and said second cladding layer comprise compositions which have a lattice match with respect to said GaAs substrate, respectively;
• said first optical waveguide layer and said second optical waveguide layer comprise compositions which have a lattice match with respect to said GaAs substrate, respectively;
• the total thickness of said first barrier layer and said second barrier layer is between 10 nm and 30 nm;
• said first barrier layer and said second barrier layer have tensile strains with respect to said GaAs substrate, respectively, and comprise a composition in which the product of a tensile strain quantity common to said two barrier layers and said total thickness is between 0.05 nm and 0.2 nm;
• said quantum well active layer comprises a composition which has a lattice match with respect to said GaAs substrate or composition which has a tensile strain of ˜0.007 with respect to said substrate;
• and
• a current non-injection region is provided near at least one of said two opposite resonator end faces of said second conduction type contact layer.

A solid-state laser apparatus comprising:

• an excitation light source;
• and
• a solid-state laser crystal for emitting laser light by being excited with excitation light emitted from said excitation light source;
• wherein said excitation light source comprises a semiconductor laser device comprising:
• a substrate, a semiconductor layer including an active layer, a cladding layer, and a contact layer stacked in the recited order;
• two exposed portions having a depth at which said semiconductor layer is exposed continuously from one of two resonator end faces to the other;
• and
• a ridge portion, formed between said two exposed portions, which has a current injection window formed in a top surface of said ridge portion;
• wherein in at least one of the resonator end faces of said ridge portion, a portion of said contact layer near said one resonator end face is removed;
• an insulating film is formed so that it covers a region, excluding said current injection window, of said contact layer, and portions of said cladding layer exposed by removing the portion of said contact layer near said one resonator end face;
• and
• an electrode is formed on at least a portion of said contact layer exposed to said current injection window.

A solid-state laser apparatus comprising:

• an excitation light source;
• and
• a solid-state laser crystal for emitting laser light by being excited with excitation light emitted from said excitation light source;
• wherein said excitation light source comprises a semiconductor laser device comprising:
• two opposite resonator end faces where at least a first conduction type first cladding layer, a first conduction type or i-type first optical waveguide layer, an i-type Inx2Ga1−x2As1−y2Py2 first barrier layer having tensile strain (where x2/0.49≦y2≦0.3+(x2/0.49), and 0.8≦y2≦1.0), an i-type Inx3Ga1−x3As1−y3Py quantum well active layer (where 0.3≦x3≦0.2 and y3=x3/0.49), an i-type Inx2Ga1−x2As1−y2Py2 second barrier layer having tensile strain (where x2/0.49≦y2≦0.3+(x2/0.49), and 0.8≦y2≦1.0), a second conduction type or i-type second optical waveguide layer, a second conduction type second cladding layer, a second conduction type contact layer, are stacked on a first conduction type GaAs substrate in the recited order;
• wherein said first cladding layer and said second cladding layer comprise compositions which have a lattice match with respect to said GaAs substrate, respectively;
• said first optical waveguide layer and said second optical waveguide layer comprise compositions which have a lattice match with respect to said GaAs substrate, respectively;
• the total thickness of said first barrier layer and said second barrier layer is between 10 nm and 30 nm;
• said first barrier layer and said second barrier layer have tensile strains with respect to said GaAs substrate, respectively, and comprise a composition in which the product of a tensile strain quantity common to said two barrier layers and said total thickness is between 0.05 nm and 0.2 nm;
• said quantum well active layer comprises a composition which has a lattice match with respect to said GaAs substrate or composition which has a tensile strain of ˜0.007 with respect to said substrate;
• and
• a current non-injection region is provided near at least one of said two opposite resonator end faces of said second conduction type contact layer.