Improving the extinction bandwidth of MMI chalcogenide photonic chip based MIR nulling interferometers

Harry Dean Kenchington Goldsmith, Michael Ireland, Pan Ma, Nick Cevetojevic, Stephen Madden

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Research into planets beyond our own star system has until recently relied on indirect imaging methods. Direct imaging methods are now establishing a foothold in the hunt for alien planets and habitable worlds. Nulling interferometry is a promising approach for suppressing the host star brightness and resolving surrounding planets. A key requirement in this method is the interference of light from multiple telescopes/baselines and free space optical devices have already rendered images of other worlds. Photonic chip based systems are also becoming accepted as means of accomplishing this but require, in particular, wide bandwidth, high precision on chip beam splitters. In this paper a design improvement is outlined to one of the most fabrication tolerant integrated beam splitter components that significantly increases its coupling bandwidth and therefore its bandwidth at high extinction. Preliminary experimental results from a fabricated device are also shown. The predicted bandwidth spans 3.8 - 4.1 µm at an extinction of ∼50 dB but at the expense of increasing the loss to 0.6 dB in transmission.

Original languageEnglish
Pages (from-to)16813-16824
Number of pages12
JournalOptics Express
Issue number14
Publication statusPublished - 10 Jul 2017
Externally publishedYes


  • Astronomy and astrophysics
  • Integrated optics
  • Photonic integrated circuits


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