SH011-0007
Enabling polar coverage of solar photospheric fields with miniature, photonic magnetographs

Tuesday, 8 December 2020
Poster
Neal E Hurlburt, Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA, United States, Gopal Vasudevan, Lockheed Martin Advanced Technology Center, Palo Alto, CA, United States, Ben Yoo, University of California, Davis, Davis, CA, United States, Humphry Chen, Lockheed Martin ATC, Palo Alto, CA, United States, Lawrence Shing, Lockheed Martin Advanced Technology Center, Palo Alto, United States and Joseph Mobilia, Lockheed Martin Space Systems, Cupertino, CA, United States
Abstract:
We present progress on developing a novel magnetograph that leverages advances in photonics integrated circuits (PICs) and low noise lasers which have been driven largely by the needs of the telecommunications industry. In our design, a single PIC replaces the traditional optical components by exploiting interferometric imaging techniques developed as part of the SPIDER project, a collaboration with LM and UC Davis. Our PIC processes incoming near infrared signals via two, independent waveguide circuits to capture each circular polarization. Narrow band spectroscopy is achieved by heterodyning the signals with a common local oscillator provided by a tunable laser. The resulting RF signals are processed using standard techniques from radio astronomy and solar magnetometry.

The optics package for our laboratory prototype observes the full disk of the sun, achieving 16 arc second resolution with a square, 2cm wafer. The technology is scalable to sub-arc second resolution using larger wafers, resulting in 100x reductions in volume and mass when compared to traditional designs. The cost of these wafers leads to a comparable reduction in the overall instrument cost since they are printed on silicon wafers using lithographic methods developed for microelectronics rather than by precise manual assembly. Small, solid wafers do not need expensive structures to maintain precise optical alignments during launch or on orbit, which further reduced size and cost.

The penalty for this compactness is an increase in computational and data management requirements. The objectives of our project are threefold:

  • Produce a set of PICs to capture the infrared solar signal and transform it into the RF domain where it can be processed using standard radio astronomy and helioseismology methods.
  • Assess the performance of the system and explore alternative processing strategies.
  • Develop the next generation PIC design and RF processing concept based on our results in preparation for a future flight opportunity.

Our single-wafer magnetographs could be deployed throughout the heliosphere to form cost effective small-sat constellations with resolutions comparable to existing space-borne instruments.

<< Previous Abstract | Next Abstract