Print ISSN: 1811-9212

Online ISSN: 2617-3352

Keywords : Thin film


The Effect of Mode Area and Refractive Index for Optical TE Mode Propagation in Hybrid LN/Si Electro-Optic Structure of Mach-Zehnder Modulator

Luma Z Mohammed; Sarah M. Taleb; Makram A. Fakhri

IRAQI JOURNAL OF COMPUTERS, COMMUNICATIONS, CONTROL AND SYSTEMS ENGINEERING, 2020, Volume 20, Issue 4, Pages 71-77

We propose and analyse a silicon based hybrid modulator on the nano thin film of the lithium niobate or commonly known as silicon-on-insulator technology. The Mach–Zehnder stripe optical waveguide of electro-optical modulator operats at GHz frequencies with large bandwidth and low losses between electrical and optical frequencies.The design and simulation of Mach-Zehnder modulator is based on a hybrid integration platform of silicon and lithium niobate that satisfies a single mode condition. The Silicon stripe waveguide is of 0.6 μm thickness in a silicon on insulator (SOI) of width 15 um and 0.05 um thickness x-cut LiNbO3 thin film, all sets use the pulse laser deposition (PLD) method. The Optical electric field distributions and effective mode area in the optical-waveguides were studied and discussed in this designated waveguide.The relationship between the width of waveguides regions with effective mode index and effective mode area was investigated. At 0.6 um width of waveguide and 0.2 um thickness, the effective mode index 1.9802 was recorded while the effective mode area 0.144 um2 was monitored. This shows the decrement in both: the width and thickness of the waveguide with the effective mode index and effective mode area.

Optical and Structural investigations of LiNbO3 thin films by PLD

Sarah M. Taleb; Makram A. Fakhri; Salah Aldeen Adnan

IRAQI JOURNAL OF COMPUTERS, COMMUNICATIONS, CONTROL AND SYSTEMS ENGINEERING, 2020, Volume 20, Issue 1, Pages 16-23

Lithium niobate (LiNbO3) nanostructure thin film was prepared and deposited on the substrates made of quartz by utilizing pulse laser deposition (PLD) technique. The effect of substrate temperature changing on the optical and structural properties of LiNbO3 films was investigated and studied. The chemical mixture was prepared by mixing the raw material (Li2CO3, Nb2O5) with Ethanol liquid without any further purification, at the stirrer time 3hrs without heating, then the formed material was overexposed to annealing process at 1000°C for 4hrs. LiNbO3 nanostructure thin film was characterized and analyzed by utilizing the Ultra-Violet visible (UV-vis) and X-Ray Diffraction (XRD). The UV-vis results showed that the increase in the substrate temperature to 300°C leads to decrease in the values of transmission (T%), absorption (A) and optical energy gap (Eg) and increase in the values of reflection (R%) and refractive index (n). While, the XRD results explained that the LiNbO3 structure became more pure and crystalline with increase the substrate temperature, because the intensity of the phase 2θ at the value of 34.8°, 40.06° and 48.48° correspond to (110), (113) and (024) planes disappeared at the substrate temperature 300°C. So, all presented results give a good indication to use LiNbO3 nanostructure thin film prepared at the substrate temperature 300°C for manufacturing the optical waveguide to give the best results