Semiconductor surface emitting lasers, laser arrays and polarization control.

摘要

This dissertation describes the design, fabrication and testing of semiconductor surface emitting lasers and laser arrays and efforts to provide polarization control for these elements. These semiconductor components are expected to be applied in systems for high throughput optical interconnect, ultra-fast optical communications and secure systems employing single photon emission.; The dissertation contains two main topic areas. The first part discusses 20x20 sapphire-bonded substrate emitting 850nm Vertical Cavity Surface Emitting Laser (VCSEL) arrays. Careful control of wafer bonding, epitaxial growth uniformity, dry etching, and metallization enabled us to achieve good performance and uniformity on large VCSEL arrays. The more significant improvement was demonstrated through successfully solving AlGaAs wet oxidation control issues. Excellent oxide aperture size uniformity was achieved. A 100% laser yield and excellent lasing performance uniformity of large 20x20 sapphire-bonded 850nm VCSEL arrays were demonstrated. The average threshold current was 448muA +/- 25muA. At 2.18mA driving current, the output power is 1mW+0.02mW across the array. The average slope efficiency is 0.55 mW/mA +/- 0.016 mW/mA. All these characteristics satisfy the 10% uniformity target. A resistance as small as 120O at 1mW lasing output and a threshold current as small as 210muA was demonstrated on a 2.5mum aperture single fundamental mode top emission VCSEL.; The second part reports development of a dynamic polarization switching VCSEL (PVCSEL). Starting from a general concept, we developed physics hypothesis, device designs, fabrications processes and characterization techniques over three generations of PVCSELs. Polarization switching by rotating the current injection direction was demonstrated. Good lasing performance was demonstrated on these specially structured, highly asymmetrically contacted, VCSELs, which included small threshold current (0.6∼0.7mA), larger than 1mW lasing output power, good slope efficiency (0.6mW/mA), and a reasonably small resistance (210O minimum). The causes for the observed stable lasing polarization were explored. Ion-Implanted Tunneling Junction 850nm PVCSELs were also explored.; The third part mainly describes a unique, integrated photonic crystal defect laser that utilizes wafer bonding and wet oxidation techniques for demonstrating electrically-pumped continuous wave lasing. Optically-pumped, AlGaAs-aperture PCDL was demonstrated. Electrically-pumped resonances were observed.