Fabrication and characterization of 1.3-µm InAs quantum-dot VCSELs and monolithic VCSEL arrays

We present fabrication and characterization of 1.3-µm InAs quantum dot (QD) vertical cavity surface emitting lasers (VCSELs) and QD-VCSEL arrays. The continuous-wave (CW) output power of single QD-VCSEL of 1.2 mW with lasing wavelength of 1.28 µm is obtained at room temperature (RT) at a bias current of 15 mA without power saturation. The low threshold current of 1.1 mA can be achieved for the single mode device. We investigate the 3-dB modulation bandwidth of QD-VCSELs with oxide aperture size of 5-µm, 10-µm and 15-µm in the small signal frequency response measurements. Modulation bandwidth of 2.65 GHz is achieved for single-mode QD-VCSEL with oxide aperture size of 5 µm at a bias current of 4.5 mA. The maximum modulation bandwidth of 2.5 GHz can be obtained for multimode QD-VCSEL with oxide aperture size of 10 µm at a bias current of 7 mA. The 61 QD-VCSELs array is also investigated at RT without optimization. Maximum CW output power of 28 mW and pulsed output power of 18 mW are demonstrated for 2-D QD-VCSEL array with threshold current of 50 mA. The far field pattern beam angle of QD-VCSEL arrays at two perpendicular directions are about 18 degree.