Fabrication and characterization of glass-semiconductor integrated waveguide amplifier by pulsed laser deposition

The phosphate modified tellurite (PT) glasses were investigated for their potential applications of bulk glass and PLD films as glass-on-semiconductor integrated thin films for engineering a semiconductor pump source integrated waveguide amplification medium which can operate at a wavelength of 1500nm. High quality PT bulk glasses were used as PLD target for deposition of high quality thin films on the silica buffered GaAs substrate by using optimized deposition parameters; target-to- substrate distance, processing gas pressure, deposition temperature and laser energy. The propagation loss of the deposited films was measured as low as 2.3 dB/cm at a wavelength of 633 nm. The Er3+: 4I13I24I15/2 optical transition lifetime response was measured as 2.5 ms. However, a dramatic increasing in the measured lifetime value was recorded by increasing the deposition temperature. Although, deposited PT films shows crack free structure (in the 200nm range), the material transfer from the bulk target to the deposited films was observed to be non-stoichiometric transfer for rare-earth elements, and for host materials a stoichiometric transfer of the materials was observed. The effects of changing the ambient gas composition on the surface morphology of the deposited PLD film was investigated and it was found that using Oxygen-Helium gas mixture produce of a ceramic-like structure in deposited thin films. The ultrafast laser micromachining was used for thin film waveguide fabrication. However, strip loaded waveguide structures were carried out using conventional photolithography followed by reactive ion etching of Si3N4. Buried waveguide structure were fabricated using ultrafast laser micromachining technique in the bulk PT glasses, and maximum gain of 3.2 dB was recorded at the erbium peak for a 21 mm long waveguide using pump wavelength of 976 nm. However, for the ridge waveguide structure a non-inverted signal gain response with internal gain peak of 2.69 dB at 1565 nm for a 11 mm long waveguide was recorded in the deposited film on the silica substrate. Glass-on- semiconductor integrated waveguide structure was fabricated using Si3N4 as strip layer, and satisfactory ASE response to the 976 pump light was recorded.EThOS - Electronic Theses Online ServiceGBUnited Kingdo