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Astrophotonics (AP)

One of the problems of contemporary astronomical instrumentation is the economical and structural sustainability of conventional bulk optic instrumentation in the coming era of extremely large telescopes. Additionally, the increasing need for large statistical datasets in astronomical research requires the simultaneous observation of many objects. Both trends point towards a massive increase of the size, mass and cost of the instruments which may overwhelm the cost of the telescope itself.

Astrophotonics could provide a solution to this vicious circle by providing miniaturized, light-weight components based on advanced micro-optics and laser technologies (photonics). Invented 30 years ago, multi-object spectrographs exploiting optical fibers are currently able to observe 100’s of astronomical objects simultaneously, allowing large surveys of stars and galaxies in our universe. Additionally, astrophotonics dramatically improves the performance/accuracy of astronomical instrumentation, as for the case of miniaturized beam combiners for astronomical interferometry based on integrated optics, phase mask coronagraphs, or laser frequency combs for ultra-precise calibration of high resolution spectrographs. As a general trend in the years to come, the miniaturization, the increased performance and the reduced needs for instrumentation maintenance will be the cornerstones of astrophotonic developments, with integrated optics technologies playing a major role.

The project “Integrated Astrophotonics” at innoFSPEC aims at a comprehensive investigation of application of integrated optics to astrophotonics, encompassing the development of components, laboratory test in realistic conditions, and, possibly, their test on sky. Additionally, by addressing cutting-edge technologies the team is committed to contribute significantly to the advance of fundamental and applied photonics, which may open the way to significant technology transfer to industry on a medium time scale.

“Integrated Astrophotonics” includes five main research activities:

Discrete Beam Combiner

The interferometry activity of the Astrophotonics group addresses the development of three-dimensional integrated-optics beam combiners for infrared stellar interferometry.

Optical Frequency Combs

Optical frequency combs (OFC) are light sources consisting of a regular array of narrow spectral lines.

AO-assisted Astrophotonics

Atmospheric turbulence is the main limiting factor for the achievement of high-resolution images with single aperture, ground based telescopes.

Arrayed Waveguide Grating and Echelle Gratings

Integrated spectrometers on the basis of AWGs and photonic Echelle gratings are important instruments for airborne and spaceborne spectroscopic surveys.

Fibre Bragg Gratings

Low-mass stars and brown dwarfs emit a substantial fraction of their light at NIR wavelengths and NIR spectroscopy is the most efficient way to study these objects.


Dr. Kalaga Madhav

Research group leader

Phone: +49 331 / 7499-390

Topics for Bachelor theses

  • Title 1: Development of experimental method for the characterisation of uniformity in waveguide arrays
  • Title 2: Numerical design of an adaptive optics testbench for astronomical instrumentation.
  • Title 3: Explore the potential of multi-core fibres as directional stress-sensors.

Projects for students

  • Topic 1: Characterization of SiN integrated microrings and waveguides
  • Topic 2: Simulation and design of next generation SiN resonators/waveguides

Publications Astrophotonics