Oxide-confined vertical-cavity surface-emitting laser emits at 1.154 microns
Oxide-confined vertical-cavity surface-emitting laser emits at 1.154 microns
An emission wavelength of 1.154 µm has been reported from an oxide-confined quantum-dot (QD) vertical-cavity surface-emitting laser (VCSEL) by a grou¥from the Microelectronics Research Center at the University of Texas at Austin (Austin, TX). The grou¥believes it is the longest wavelength yet obtained from an electrically pumped, gallium arsenide (GaAs) based VCSEL and the longest lasing wavelength obtained from a QD. Emission at wavelengths beyond 1 µm are of interest for new applications in optical signal transmission.
The single-layer QD active region of the VCSEL is formed from five cycles of alternating indium arsenide (InAs) and GaAs monolayer depositions to obtain long-wavelength emission. Intracavity contacts are used along with undoped lower and dielectric upper distributed Bragg reflectors. A continuous-wave threshold of 502 µA is obtained for a 10-µm-diameter device, corresponding to a threshold current density of 640 A/cm2. Electroluminescence from the edge of a 20 ¥ 300-µm stripe device has broader peaks than previously reported for InGaAs QDs in this wavelength range, suggesting that the VCSEL performance might be improved with further optimization of the QD growth. The grou¥also reports that its data strongly suggest the same QD active region, and a properly tuned cavity can yield low-threshold lasing at wavelengths beyond 1.25 µm.