Paper 13100-247
Optimisation of laser-written tricouplers for nulling interferometry in the J- and H-band
20 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
Abstract
The technique of nulling interferometry is helping to overcome the challenges of directly detecting exoplanets and is the foundation for the Guided Light Interferometric Nulling Technology (GLINT) instrument located at the Subaru telescope in Hawaii. A new integrated optics beam combiner will be deployed to simultaneously perform nulling interferometry and fringe tracking. This is enabled by using a photonic device called a tricoupler. Comprising of 3 input single-mode waveguides, the tricoupler produces 3 outputs, consisting of the interferometric nulled output and two phase-sensitive bright outputs.
These 3D waveguide tricouplers are fabricated using the femtosecond laser direct-write technique. This process involves a tightly focused laser to modify the refractive index of a boro-aluminosilicate glass sample, creating optical waveguides. We present a rigorous optimisation of the tricouplers which includes a numerical solution to coupled-mode equations to obtain coupling coefficients and propagation constants that are used to optimise the fabrication process for the J (1.1 μm - 1.4 μm) and H (1.5 μm - 1.8 μm) wavelength bands. Furthermore, the polarisation behaviour, the wavelength behaviour and interferometric performance has been investigated to create an accurate transfer matrix of the device.
These 3D waveguide tricouplers are fabricated using the femtosecond laser direct-write technique. This process involves a tightly focused laser to modify the refractive index of a boro-aluminosilicate glass sample, creating optical waveguides. We present a rigorous optimisation of the tricouplers which includes a numerical solution to coupled-mode equations to obtain coupling coefficients and propagation constants that are used to optimise the fabrication process for the J (1.1 μm - 1.4 μm) and H (1.5 μm - 1.8 μm) wavelength bands. Furthermore, the polarisation behaviour, the wavelength behaviour and interferometric performance has been investigated to create an accurate transfer matrix of the device.
Presenter
Elizabeth Arcadi
Macquarie Univ. (Australia)
Elizabeth Arcadi received her Bachelor of Science majoring in Astrophysics and Astronomy at Macquarie University in Sydney Australia in 2020. She completed her Master of Research in Astrophotonics at Macquarie University in 2022 under the supervision of Dr Simon Gross and Professor Michael Withford. During her master’s she worked on 3D tricouplers fabricated using the femtosecond direct-write technique. In February of 2023 she started her PhD, continuing this work at Macquarie University. She is currently working on a new integrated beam combiner for nulling interferometry and fringe tracking to be deployed at the Subaru Telescope in Hawaii. She is also the President of the OPTICA Student Chapter at Macquarie University.