Integrated photonic building blocks for next-generation astronomical instrumentation I: the multimode waveguide
Date
2012-07-01
Authors
Jovanovic, Nemanja
Spaleniak, Izabela
Gross, Simon
Lawrence, Jon S.
Miese, Christopher
Fuerbach, Alexander
Withford, Michael J.
Ireland, Michael
Journal Title
Journal ISSN
Volume Title
Publisher
Optical Society of America
Abstract
We report on the fabrication and characterization of composite multimode
waveguide structures that consist of a stack of single-mode waveguides
fabricated by ultrafast laser inscription. We explore 2 types of composite
structures; those that consist of overlapping single-mode waveguides which
offer the maximum effective index contrast and non overlapped structures which
support multiple modes via strong evanescent coupling. We demonstrate that both
types of waveguides have negligible propagation losses (to within experimental
uncertainty) for light injected with focal ratios >8, which corresponds to the
cutoff of the waveguides. We also show that right below cutoff, there is a
narrow region where the injected focal ratio is preserved (to within
experimental uncertainty) at the output. Finally, we outline the major
application of these highly efficient waveguides; in a device that is used to
reformat the light in the focal plane of a telescope to a slit, in order to
feed a diffraction-limited spectrograph.
Description
Keywords
Keywords: Astronomical instrumentation; Building blockes; Diffraction limited; Effective index; Evanescent coupling; Experimental uncertainty; Focal Plane; Integrated photonics; Multi-mode waveguides; Multiple modes; Propagation loss; Single mode waveguides; Ultraf
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Source
Optics Express
Type
Journal article
Book Title
Entity type
Access Statement
Open Access