Optically pumped VCSEL emits at wavelengths longer than 1.25 µm

Optically pumped VCSEL emits at wavelengths longer than 1.25 µm

The longest emission wavelength yet achieved for a gallium arsenide vertical-cavity surface-emitting laser (VCSEL) has been reported by a grou¥at the Hitachi Central Research Laboratory (Tokyo, Japan). Based on a gallium indium nitrogen arsenide /gallium arsenide (GaInNAs/GaAs) multiple-quantum-well (MQW) active layer grown directly on a gallium arsenide aluminum arsenide (GaAsAlAs) distributed Bragg reflector, the optically pumped device produces continuous-wave output from 1.146 to 1.256 µm at room temperature-- indicative of the high material gain available from the three-quantum-well active layer. Lasing threshold was marked by spectral linewidth narrowing and clamping of spontaneous emission, as well as a clearly defined kink in the light output versus pum¥power. The threshold pum¥power was 5.5 to 16 kW/cm2, or an equivalent threshold current density over this range of 3.3 to 10 kA/cm2. The grou¥believes that 1.3-µm operation should be possible by increasing the indium and nitrogen content in the GaInNAs active layer.