Centre for Ultrahigh-bandwidth Devices for Optical Systems
The Centre for Ultrahigh-bandwidth Devices for Optical Systems (CUDOS) team in the Laser Physics Centre at the Australian National University fabricates planar optical waveguides and photonic crystal structures from chalcogenide glasses in support of the CUDOS program. The resulting structures are supplied to other researchers within CUDOS, involved in device development and testing, particularly those at the University of Sydney. LPC’s offices and laboratories occupying some 1500m2 of space are located in the John Carver, Cockroft and Huxley buildings in the Research School of Physics and Engineering at ANU.
Researchers in the Laser Physics Centre (LPC) are members of the ARC-funded Centre of Excellence for Ultrahigh-bandwidth Devices for Optical Systems (CUDOS). CUDOS members within LPC undertake the development of advanced optical waveguides and photonic crystal structures for the CUDOS research program with an emphasis of devices fabricated from chalcogenide glasses. These glasses in particular have been chosen because they offer high optical linear and nonlinear refractive index and broad transmission in the mid infrared. The optical devices developed in LPC are supplied to other group within CUDOS that focus on application projects. In particular they are used for research into terabit per second all-optical signal processing of telecommunications signals; for research into quantum integrated photonics; for hybrid integration to create highly functional photonic devices; and for research in mid infrared science.
The main laboratories supporting the CUDOS program comprise a glass chemistry laboratory; a clean room facility supporting film deposition, optical lithography, and plasma etching; and a waveguide testing facility that can measure waveguide properties at wavelengths spanning from the near to the middle infrared.
The 50m2 glass chemistry laboratory is dedicated to the production of purified bulk chalcogenide glasses with novel compositions and supports research into the science of chalcogenide materials which has the aim of identifying glasses which the best physical properties for applications in photonics. The laboratory contains facilities for the production of glasses using the standard melt-quenching techniques and is supported by a wide range of tools for glass characterization such as spectrophotometry; differential scanning calorimetry; Raman spectroscopy; measurement of the linear and nonlinear refractive index, etc.
Glass samples are turned into thin films deposited onto various substrates using thermal evaporation or sputtering. In 2011 a new custom deposition chamber was commissioned for the deposition of complex multicomponent glass films direct from the elements using co-thermal evaporation. This system will in particular support the production of rare-earth doped chalcogenide films that are being developed for optical amplifiers and mid-IR lasers.
Waveguides and photonic crystal devices are fabricated from the chalcogenide films using both optical and electron beam lithography. The photolithography laboratory contains an SVG-800 dual track coating and development system and is used in conjunction with a Karl Suss MA6 exposure tool to transfer waveguide patterns into photoresist masks with sub-micron resolution. Pattern transfer into the glass is then accomplished using an Oxford Instruments RIE-100 ICP plasma etching tool.
The CUDOS production requires the production of photonic crystal to create high-Q resonators that can be used for low power all-optical switching and for sensing as well as structures that support slow light propagation that can be used to enhance nonlinear optical effects. The CUDOS team uses the electron beam lithography facilities of the Australian National Fabrication Facility (ANFF) at ANU to obtain the nm-level dimensional control required to realise such devices.
Further details on the CUDOS research can be found at the Centre’s website.