Distributed feedback interband cascade lasers with corrugated sidewall

A semiconductor laser comprising:

• a ridge or buried waveguide having alternating first and second regions;
• wherein the first region has a constant width, and the second region has a width that matches that of the first region at boundaries between the first region and the second region, and the width of the second region increases to a maximum that is larger than the width of the first region, such that a partially-corrugated sidewall or interface on each side of the waveguide is formed;
• wherein the first region comprises a grating structure, and due to periodic nature of the first region, the grating structure is in a form of a sampled grating;
• and
• wherein the partially-corrugated sidewall or interface increases waveguide losses for radiation in high order lateral modes as compared to the fundamental waveguide mode.

An interband cascade laser comprising:

• a ridge waveguide having alternating first and second regions;
• wherein the first region has a constant width, and the second region has a width that matches that of the first region at boundaries between the first region and the second region, and the width of the second region decreases to a minimum that is smaller than the width of the first region, such that a partially-corrugated sidewall along each side of the ridge waveguide is formed;
• wherein the first region comprises a grating structure, and due to periodic nature of the first region, the grating structure is in a form of a sampled grating;
• and
• wherein the partially-corrugated sidewall increases waveguide losses for radiation in higher order lateral modes as compared to the fundamental waveguide mode.

A semiconductor laser comprising:

• a ridge or buried waveguide having alternating first and second regions;
• wherein the first region has a constant width, and the second region has a width that matches that of the first region at boundaries between the first region and the second region, and the width of the second region decreases to a minimum that is smaller than the width of the first region, such that a partially-corrugated sidewall or interface on each side of the waveguide is formed;
• wherein the first region comprises a grating structure, and due to periodic nature of the first region, the grating structure is in a form of a sampled grating;
• and
• wherein the partially-corrugated sidewall or interface increases waveguide losses for radiation in high order lateral modes as compared to the fundamental waveguide mode.