Low thermal resistance, high-speed 980 nm asymmetric intracavity-contacted oxide-aperture VCSELs

We demonstrated high-speed characteristics of an oxide-aperture vertical-cavity surface-emitting laser (VCSEL) with intracavity structures for both p- and n-contacts, based on InGaAs/GaAs multiple quantum wells operating at λ ∼ 980 nm, indicating a low thermal resistance (Rth). The asymmetric current injection scheme is employed for reducing current crowding around the rim of the oxide aperture. A high aluminium content undoped Al0.88Ga0.12As and GaAs distributed Bragg reflector (DBR) mirror is used for efficient heat dissipation. The VCSEL with a 7 μm oxide aperture exhibited an output power of 2.5 mW and a threshold current of 0.8 mA with a slope efficiency of 0.39 mW/mA at 20 °C under continuous-wave operation and it still worked with 1.3 mW at 90 °C. The temperature tuning coefficient of 0.081 nm/°C and dissipated electrical power tuning coefficient of 0.104 nm/mW were observed, leading to a low Rth of 1.28 °C/mW. A high modulation bandwidth up to 13 GHz with a modulation current efficiency factor of 6.1 GHz/mA1/2 was achieved. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)