Quantum Well Intermixed Two Section Superluminescent Diodes

Abstract

<p>Superluminescent diodes have become important for various applications, such as for biomedical imagining, due to their broad spectral width and high power.</p><p>This thesis demonstrates two-section superluminescent diodes fabricated using quantum well intermixing with strained Ga_0.75sln_0.25As quantum wells, grown on a GaAs substrate. A 100 nm capping layer of Ga_0.515In_0.485P grown at low temperature and having an excess of phosphorus, was removed from one section of the device to produce a relative bandgap shift between sections after rapid thermal annealing. The devices emitted at a wavelength of ~1μm with 60 nm of spectral width, and up to 38 mW of power at 20°C, depending on the currents applied to each section.</p><p>The combination of the spectral output from the two quantum well intermixed sections resulted in the broad spectral width. Angled facets at 7 ° were used to prevent the device from lasing. Additional power improvements were seen following the thermal anneal when a SiO2 capping layer was used on both sections. Depending on the applied currents, each section required 1.5 V to 3.0 V; and failed at 5.3 V ± 0.5 V.</p>