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

Abstract

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 lambda similar to 980 nm, indicating a low thermal resistance (R-th). 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 pm 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 degrees C under continuous-wave operation and it still worked with 1.3 mW at 90 degrees C. The temperature tuning coefficient of 0.081 nm/degrees C and dissipated electrical power tuning coefficient of 0.104 nm/mW were observed, leading to a low Rth Of 1.28 degrees C/mW. A high modulation bandwidth up to 13 GHz with a modulation current efficiency factor of 6.1 GHz/mA(1/2) was achieved. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim