Open AccessImproving the extinction bandwidth of MMI chalcogenide photonic chip based MIR nulling interferometers
Author(s) -
Harry-Dean Kenchington Goldsmith,
Michael Ireland,
Pan Ma,
Nick Cvetojević,
Steve Madden
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.016813
Subject(s) - optics , beam splitter , bandwidth (computing) , astronomical interferometer , interferometry , physics , photonics , chip , planet , exoplanet , computer science , optoelectronics , telecommunications , astronomy , laser
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.