Interband Cascade Lasers with Improved Voltage Efficiency

A semiconductor interband cascade (IC) laser comprising:

• an IC region having a real refractive index, the IC region configured to generate light based on interband transitions, and having a transition energy which defines an emitted photon energy and a corresponding lasing wavelength;
• a first outer plasmon cladding layer comprising a first high-doped n+-type InAs1-ySby and having a first outer plasmon cladding layer real refractive index and positioned below the IC region, wherein the first outer plasmon cladding layer real refractive index is less than the IC region real refractive index;
• a first intermediate cladding layer positioned between the IC region and the first outer plasmon cladding layer, wherein the first intermediate cladding layer comprises a first semiconductor material having a first intermediate cladding layer real refractive index which is less than the IC region real refractive index;
• a second outer plasmon cladding layer comprising a second high-doped n+-type InAs1-ySby and having a second outer plasmon cladding layer real refractive index and positioned above the IC region, and wherein the second outer plasmon cladding layer real refractive index is less than the IC region real refractive index;
• a second intermediate cladding layer positioned between the IC region and the second outer plasmon cladding layer, wherein the second intermediate cladding layer comprises a second semiconductor material having a second intermediate cladding layer real refractive index that is less than the IC region real refractive index, and wherein the first high-doped n+-type InAs1-ySby and the second high-doped n+-type InAs1-ySby have lattice constants that are approximately matched to that of GaSb;
• and
• a p-type GaSb substrate positioned below and adjacent to the first outer plasmon cladding layer.

A semiconductor interband cascade (IC) laser comprising:

• an IC region having a real refractive index, the IC region configured to generate light based on interband transitions and having a transition energy which defines an emitted photon energy and a corresponding lasing wavelength;
• a first outer plasmon cladding layer comprising a first high-doped semiconductor material and having a first outer plasmon cladding layer real refractive index and positioned below the IC region, and wherein the first outer plasmon cladding layer real refractive index is lower than the IC region real refractive index;
• a first intermediate cladding layer positioned between the IC region and the first outer plasmon cladding layer, wherein the first intermediate cladding layer comprises a first semiconductor material having a first intermediate cladding layer real refractive index which is lower than the IC region real refractive index;
• a second outer plasmon cladding layer comprising a second high-doped semiconductor material and having a second outer plasmon cladding layer real refractive index and positioned above the IC region, and wherein the second outer plasmon cladding layer real refractive index is lower than the IC region real refractive index;
• a second intermediate cladding layer positioned between the IC region and the second plasmon outer cladding layer, wherein the second intermediate cladding layer comprises a second semiconductor material having a second intermediate cladding layer real refractive index that is lower than the IC region real refractive index;
• a substrate positioned below and adjacent to the first outer plasmon cladding layer;
• and
• a first metal contact connected to the first outer plasmon cladding layer.