Two different lasers integrated in a monochip by one-step epitaxy

A new way to integrate two different lasers (LD1: 950 nm and LD2: 990 nm) in a monochip by one-step epitaxial growth is presented. These two lasers are cascaded by a high-doping tunnel junction that separates the two active regions so that a four-terminal device can be implemented, which permits the operation of the lasers electrically independent as LD1, LD2, and LD1+LD2 after fabrication process. High power dual-wavelength operation laser diodes are fabricated, output power as high as 3.1 W at 3 A and 2.4 W at 2 A is obtained, and the slope efficiency can reach 1.38 W/A. As for four-terminal integrated laser diodes, the threshold current is 54, 58, and 65 mA, and the slope efficiency is 0.73, 0.48, and 0.37 for the LD1+LD2, LD1, and LD2, respectively.