The size and cost of astronomical instruments for extremely large telescopes (ELTs), are pushing the limits ofwhat is feasible, requiring optical components at the very edge of achievable size and performance. Operating atthe diffraction-limit, the realm of photonic technologies, allows for highly compact instruments to be realized. Inparticular, Integrated Photonic Spectrographs (IPSs) have the potential to replace an instrument the size of acar with one that can be held in the palm of a hand. This miniaturization in turn offers dramatic improvementsin mechanical and thermal stability. Owing to the single-mode fiber feed, the performance of the spectrographis decoupled from the telescope and the instruments point spread function can be calibrated with a much higherprecision. These effects combined mean that an IPS can provide superior performance with respect to a classicalbulk optic spectrograph.In this paper we provide a summary of efforts made to qualify IPSs for astronomical applications to date.These include the early characterization of arrayed waveguide gratings for multi-object injection and modifica-tions to facilitate a continuous spectrum, to the integration of these devices into prototypical instruments andmost recently the demonstration of a highly optimized instrument directly fed from an 8-m telescope. We willthen outline development paths necessary for astronomy, currently underway, which include broadening operat-ing bands, bandwidth, increasing resolution, implementing cross-disperison on-chip and integrating these deviceswith other photonic technologies and detectors such as superconducting Microwave Kinetic Inductance Detectorarrays. Although the focus of this work is on IPS applicability to astronomy, they may be even more ideallysuited to Earth & planetary science applications.
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