title: Developing arrayed waveguide grating spectrographs for multi-object astronomical spectroscopy.
abstract: With the aim of utilizing arrayed waveguide gratings for multi-object spectroscopy in the field of astronomy, we outline several ways in which standard telecommunications grade chips should be modified. In particular, by removing the parabolic-horn taper or multimode interference coupler, and injecting with an optical fiber directly, the resolving power was increased threefold from 2400 ± 200 (spectral resolution of 0.63 ± 0.2 nm) to 7000 ± 700 (0.22 ± 0.02 nm) while attaining a throughput of 77 ± 5%. More importantly, the removal of the taper enabled simultaneous off-axis injection from multiple fibers, significantly increasing the number of spectra that can be obtained at once (i.e. the observing efficiency). Here we report that ~12 fibers can be injected simultaneously within the free spectral range of our device, with a 20% reduction in resolving power for fibers placed at 0.8 mm off-centre.
authors.affiliation: MQ Photonics Research Centre, Department of Physics and Astronomy, Macquarie University, NSW 2109, Australia. nick.cvetojevic@mq.edu.au
authors.forename: Nick
authors.initials: N
authors.lastname: Cvetojevic
authors.forename: Nemanja
authors.initials: N
authors.lastname: Jovanovic
authors.forename: Jon
authors.initials: J
authors.lastname: Lawrence
authors.forename: Michael
authors.initials: M
authors.lastname: Withford
authors.forename: Joss
authors.initials: J
authors.lastname: Bland-Hawthorn
mesh_terms: D001256:Astronomy / Q000295:instrumentation*; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D008962:Models, Theoretical; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation; D013057:Spectrum Analysis / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D013685:Telecommunications / Q000295:instrumentation*