READ ME File For 'DATASET for Wideband mid-infrared group IV photonic devices and platforms'

Dataset DOI: https://doi.org/10.5258/SOTON/D2012

ReadMe Author: Callum J. Stirling, University of Southampton
Contact: c.stirling@soton.ac.uk

This dataset supports the thesis:
Callum John Stirling
Wideband mid-infrared group IV photonic devices and platforms

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Description:
The file 'Dataset_for_WidebandG4_thesis.xlsx' contains all simulation and experimental data.

Fig. 2.4: Simulation data for the modal effective refractive indices of the first three modes in a 1.2 µm x 0.5 µm SOI strip waveguide.
Fig. 4.3: Simulation data for the modal effective refractive indices of the ESM waveguide mode and the first two TE modes in a 1.2 µm x 0.5 µm SOI strip waveguide.
Fig. 4.5: Simulation data for the bending loss of the ESM waveguide.
Fig. 4.6: Calculated subwavelength threshold for different wavelengths using Eq. 4.3 in the thesis.
Fig. 4.7: Measured data for the cut-back measurements of the endlessly single-mode SOI waveguides with thinner cladding, at around 3.8 µm wavelength.
Fig. 4.8: Measured data for the cut-back measurements of the endlessly single-mode SOI waveguides, at around 1.95 µm and 3.80 µm wavelengths.
Fig. 4.12(a,c,e): Captured images of the waveguide outputs at 1950nm wavelength (for ESM, single-mode and multimode waveguides) before normalisation to largest pixel intensity for each image.
Fig. 4.12(b): Data for the output intensity heatmap for the ESM waveguide, before normalisation.
Fig. 4.12(d): Data for the output intensity heatmap for the single-mode waveguide, before normalisation.
Fig. 4.12(f): Data for the output intensity heatmap for the multimode waveguide, before normalisation.
Fig. 5.2: MMI beat lengths calculated from Eqs. 5.1 and 5.4 in the thesis. The effective index for the conventional waveguide was obtained using MODE eigensolver.
Fig. 5.3: Data for the simulated performance of the optimal SWG-MMI.
Fig. 5.7: Data for the transmission spectra and the fitted analytical model for the MZI using (a) SWG-MMIs and (b) conventional MMIs.
Fig. 5.8: Data for (a) imbalance, (b) insertion loss and (c) phase error for SWG and conventional MMIs, extracted from fitting of MZI transmission spectra, alongside simulated performance for the fabricated device.
Fig. 6.1: Simulated effective indices of a 500 nm-thick fully etched SOI waveguide for the TE0 and TE1 modes.
Fig. 6.4: Results of the PSO for the optimisation of the Y-junction geometry.
Fig. 6.8: Measured data for the "chain" layout to determine the insertion loss of the optimised Y-junctions.
Fig. 7.8: Simulation of the effective index of the TE1 mode in a 1.5µm-thick Si-on-ZnSe waveguide (note: etch depth = 1.5 µm - slab thickness).
Fig. 7.11: Grating coupler efficiency (maximum = 1) for a Si-on-ZnSe waveguide with 1.1 µm etch depth.
Fig. 7.17: Measurement of out-of-plane bending caused by silicon membrane deformation.
Fig. 7.19: Measured data for the transmitted signal through the Si-on-ZnSe waveguide and reflected background signal.
Fig. 7.20: Simulated coupling between two Si-on-ZnSe waveguides with w=2.5µm, d=1.05µm and h=1.5µm, calculated from the difference between the first two supermodes in the waveguides in MODE.
Fig. 7.21: Change in effective index of the fundamental waveguide mode by placing vias depending on waveguide centre-to-via centre separation.
Fig. 7.22: Simulated bending loss of the Si-on-ZnSe, accounting for the effect of the vias.
Fig. 7.23: Grating coupler efficiency (maximum = 1) for a Si-on-ZnSe and suspended Si waveguides with 1.05 µm etch depth.
Fig. 7.24: Simulated transmission in the Si-on-ZnSe taper as a function of length (maximum = 1), with input and output waveguides with widths of 10 μm and 2.5 μm respectively. Simulated in EME.
Fig. 7.25: Simulated loss in a waveguide S-bend with a fixed offset of 30 μm. Simulated in varFDTD.

Further, the file 'IntensityHeatmapMATLAB.zip' contains the following:
- 'IntensityHeatmap.m': a MATLAB script that will generate all figures in Fig. 4.12, using 'EndlesslySingleMode.mat', 'SingleMode.mat' and 'Multimode.mat'.
- 'EndlesslySingleMode.mat': a data file, containing a 31x31 pixel image at each wavelength step, centred on the output of the ESM waveguide (cropped from recorded images that were 320x256 pixels)
- 'SingleMode.mat': a data file, containing a 31x31 pixel image at each wavelength step, centred on the output of the single-mode waveguide (cropped from recorded images that were 320x256 pixels)
- 'Multimode.mat': a data file, containing a 31x31 pixel image at each wavelength step, centred on the output of the multimode waveguide (cropped from recorded images that were 320x256 pixels)
- 'laser_spectrum.txt': a data file, containing the laser spectrum as a fraction of its peak output intensity, taken from the manual for the Thorlabs TLK-L1950R using WebPlotDigitizer (https://automeris.io/WebPlotDigitizer/).

The file 'MMIfittingMATLAB.zip' contains the following:
- 'SpectrumFitGA.m': a MATLAB script for fitting the MZI spectra to calculate the MMI performance
- 'MZI.m': a MATLAB function for calculating the output of an MZI
- 'lorentz.m': a MATLAB function for estimating the effect of the laser linewidth
- 'Conventional.fig': a data file, containing the spectrum of an MZI with embedded conventional MMIs
- 'SWG.fig': a data file, containing the spectrum of an MZI with embedded SWG-MMIs
- 'noisefloor.mat': a data file, containing the estimation of the noise floor of the experimental setup

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Geographic location of data collection: University of Southampton, UK

Date of data collection 2017-09-28 to 2021-10-27


Dataset available under a CC BY 4.0 licence


Publisher: University of Southampton, U.K.


Date: October 2021