Rare - Earth Doped Aluminum Oxide Lasers for Silicon Photonics by Emir Salih Magden

A reliable and CMOS-compatible deposition process for amorphous Al2O3 based active photonic components has been developed. Al2O3 films were reactively sputtered, where process optimization was achieved at a temperature of 250 C, with a deposition rate of 8.5 nm/min. With a surface roughness of 0.3 nm over a 1 μm area, background optical losses as low as 0.1 dB/cm were obtained for undoped films. The development of active photonics components has been realized by use of rare-earth metals as dopants. By cosputtering aluminum and erbium targets, Er dopants at concentrations on the order of 1.0x10 cm have been added to the Al2O3 host medium. Resulting Er3+:Al2O3 films have been characterized, and over 3 dB/cm absorption has been measured over a 20 nm bandwidth. Following the material development, distributed Bragg reflector lasers were designed and fabricated in a CMOS foundry. The laser cavity was created by introducing gratings on either side of a Si3N4 waveguide. Er 3+:Al2O3 was deposited in SiO2 trenches on top of the Si3N4 layer, eliminating the need for any subsequent etching steps. On-chip laser output of 3.9 μW has been recorded at a wavelength of 1533.4 nm, with a side mode suppression ratio over 38.9 dB. Thesis Supervisor: Leslie A. Kolodziejski Title: Professor of Electrical Engineering and Computer Science