Laterally coupled distributed feedback cascade diode lasers emitting near 2.9 ?m

Cascade type-I quantum well GaSb-based laterally coupled distributed feedback diode lasers emitting near 2.9 ?m were designed and fabricated. Second order index grating with period of 825 nm was defined by e-beam lithography and etched on both sides of 4-?mwide shallow ridge waveguide. Anti-/neutral reflection coated 2-mmlong devices that were solder-mounted epitaxial side-up demonstrated stable single frequency operation in a wide temperature range with output power of 13 mW at 20C. Bragg wavelength temperature tuning rate was ?0.32 nm/K.