A conventional Arrayed Waveguide Grating (AWG) has been tailored for non-conventional applications such as Astro-Photonics, Life-science and spectroscopy where the input signal can have information over the full continuum of light/spectrum, compared to discrete optical channels in optical communication systems. The material system chosen for the AWG design is silicon-nitride/SiO₂/Si (Si₃N₄-SiO₂-Si) for it's relatively high refractive index, which for a given channel spacing allowing a more compact device than Silicon-on-Silica. While existing conventional AWGs cannot be utilized in spectroscopy when the input is a continuum, due to the fixed output waveguides where the centre wavelength λ_c and therefore rest of the wavelength channels have been assigned to predetermined output waveguides, the device under development has no output waveguides permitting to utilize the entire-image plane of the output star-coupler. The output of the AWG can then be re-imaged onto a detector array to sample the entire output spectrum, such as the 2-D infrared arrays used in astronomy. The designed AWG can resolve up to 40 spectral channels with wavelength spacing 0.4nm (50GHz), adjacent channel cross-talk level < -25dB at the ITU grid (25GHz) and non-uniformity ~ 2.5dB. The modeled mean spectral resolving power, R, at the flat image-plane is ~ 12,200.

Date Published: 10 May 2012
PDF: 9 pages
Proc. SPIE 8431, Silicon Photonics and Photonic Integrated Circuits III, 84311U (10 May 2012); doi: 10.1117/12.923145

Published in SPIE Proceedings Vol. 8431:
Silicon Photonics and Photonic Integrated Circuits III
Laurent Vivien; Seppo K. Honkanen; Lorenzo Pavesi; Stefano Pelli, Editor(s)