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Full-Text Articles in Engineering
Low-Loss, Compact, Spot-Size-Converter Based Vertical Couplers For Photonic Integrated Circuits, Praveen K.J. Singaravelu, G.C.R. Devarapu, Sebastian A. Schulz, Quentin Wilmart, Stéphane Malhouitre, Ségolène Olivier, Liam O’Faolain
Low-Loss, Compact, Spot-Size-Converter Based Vertical Couplers For Photonic Integrated Circuits, Praveen K.J. Singaravelu, G.C.R. Devarapu, Sebastian A. Schulz, Quentin Wilmart, Stéphane Malhouitre, Ségolène Olivier, Liam O’Faolain
Cappa Publications
In recent years, the monolithic integration of new materials such as SiN, Ge and LiNbO3 on silicon (Si) has become important to the Si photonics community due to the possibility of combining the advantages of both material systems. However, efficient coupling between the two different layers is challenging. In this work, we present a spot size converter based on a two-tier taper structure to couple the optical mode adiabatically between Si and SiN. The fabricated devices show a coupling loss as low as 0.058 dB ± 0.01 dB per transition at 1525 nm. The low coupling loss between the Si …
Mid-Infrared Optical Sensing Using Sub-Wavelength Gratings, Brian Hogan, Liam Lewis, Michael Mcauliffe, Stephen P. Hegarty
Mid-Infrared Optical Sensing Using Sub-Wavelength Gratings, Brian Hogan, Liam Lewis, Michael Mcauliffe, Stephen P. Hegarty
Cappa Publications
Optical sensing has shown great potential for both quantitative and qualitative analysis of compounds. In particular sensors which are capable of detecting changes in refractive index at a surface as well as in bulk material have received much attention. Much of the recent research has focused on developing technologies that enable such sensors to be deployed in an integrated photonic device. In this work we demonstrate experimentally, using a sub-wavelength grating the detection of ethanol in aqueous solution by interrogating its large absorption band at 9.54 µm. Theoretical investigation of the operating principle of our grating sensor shows that in …
Effects Of Fabrication Errors On The Focusing Performance Of A Sector Metalens, S. S. Stafeev, A. G. Nalimov, Liam O’Faolain, M. V. Kotlyar
Effects Of Fabrication Errors On The Focusing Performance Of A Sector Metalens, S. S. Stafeev, A. G. Nalimov, Liam O’Faolain, M. V. Kotlyar
Cappa Publications
Using e-beam lithography, a 16-sector spiral metalens was fabricated in an amorphous silicon, capable of converting linearly polarized incident light into an azimuthally polarized optical vortex. When illuminated by a 633-nm linearly polarized laser beam, the metalens generated a near-surface subwavelength focal spot equal to 0.75 of the incident wavelength at full-width of half-maximum intensity. The focusing performance of the spiral metalens was numerically shown to be sensitive to the deviation of the factual microrelief from the calculated height. For the designed microrelief height, a circularly polarized incident beam was focused into a bright ring with a reverse energy flow …