| The purpose of this dissertation is to realize reliable and practical long-wavelength vertical-cavity surface-emitting lasers (VCSELs) for real optical fiber communications. The approach is to deploy all-lattice-matched structures on InP, which have been already proven to provide high performance, reliability, low cost, and high manufacturability by GaAs-based shorter-wavelength (850–980 nm) VCSELs. AlGaAsSb is a promising material to implement highly reflecting distributed Bragg reflectors (DBRs) which are lattice-matched to InP. However, the high operating voltage and high thermal impedance caused by the AlGaAsSb/AlAsSb DBRs result in the large temperature rise, preventing CW operation.; The primary advance in this dissertation is a double-intracavity contacted structure. This structure allows generated heat and injected current to bypass the Sb-based mirrors, reducing the temperature increase. The device has demonstrated excellent performance such as high maximum output power (>1 mW at 20°C and >100 μW at 80°C) and high maximum operation temperature (88°C) for the 8 μm aperture. The InP-lattice-matched VCSEL fully benefits from the double-intracavity contacted structure in terms of the device temperature, since the measured operating voltage and thermal impedance are comparable with the GaAs-lattice-matched structures.; There are several parameters to be improved for the higher temperature and higher output operation. The low injection efficiency results from the small overlap of optical mode and current density profile, which will be increased using two separate oxide apertures for current and optical confinements. The relatively low characteristic temperature of the injection efficiency and threshold current must be improved by optimizing the material quality of the active region. |
