[Paper Review] Enabling the next generation of scientific discoveries by embracing photonic technologies

Nemanja Jovanović, Charles Beichman+47 more|arXiv (Cornell University)|Jul 17, 2019

Photonic Crystal and Fiber Optics68 references4 citations

TL;DR

This white paper advocates for a $20 million investment over 5–10 years to accelerate the development of integrated photonic spectroscopy (IPS) technologies, enabling compact, high-performance instruments for extremely large telescopes (ELTs) and space missions. By leveraging mature telecom photonics adapted for astronomy, the approach promises to overcome current instrument size, cost, and performance limitations, with a focus on waveguide-based devices, improved coupling efficiency, and commercial scalability.

ABSTRACT

The fields of Astronomy and Astrophysics are technology limited, where the advent and application of new technologies to astronomy usher in a flood of discoveries altering our understanding of the Universe (e.g., recent cases include LIGO and the GRAVITY instrument at the VLTI). Currently, the field of astronomical spectroscopy is rapidly approaching an impasse: the size and cost of instruments, especially multi-object and integral field spectrographs for extremely large telescopes (ELTs), are pushing the limits of what is feasible, requiring optical components at the very edge of achievable size and performance. For these reasons, astronomers are increasingly looking for innovative solutions like photonic technologies that promote instrument miniaturization and simplification, while providing superior performance. Astronomers have long been aware of the potential of photonic technologies. The goal of this white paper is to draw attention to key photonic technologies and developments over the past two decades and demonstrate there is new momentum in this arena. We outline where the most critical efforts should be focused over the coming decade in order to move towards realizing a fully photonic instrument. A relatively small investment in this technology will advance astronomical photonics to a level where it can reliably be used to solve challenging instrument design limitations. For the benefit of both ground and space borne instruments alike, an endorsement from the National Academy of Sciences decadal survey will ensure that such solutions are set on a path to their full scientific exploitation, which may one day address a broad range of science cases outlined in the KSPs.

Motivation & Objective

• Address the growing technological bottleneck in astronomical spectroscopy, particularly for multi-object and integral field spectrographs on extremely large telescopes (ELTs), where instrument size and cost are reaching feasibility limits.
• Overcome the slow adoption of photonic technologies in astronomy due to challenges in optical coupling, high re-engineering costs, immature components, and conservative institutional attitudes.
• Accelerate the maturation and integration of photonic technologies—especially integrated photonic spectrographs (IPS)—into major astronomical facilities by developing standardized, scalable, and cost-effective solutions.
• Establish a public-private partnership model to de-risk and accelerate the transition of photonic components from research to flight-ready instruments, ensuring U.S. leadership in next-generation astrophysical observations.

Proposed method

• Adapt mature telecom photonics technologies (e.g., optical fibers and integrated circuits) optimized for O- and C-bands to astronomical wavelengths (e.g., 1–2.5 μm), focusing on silica-on-silicon, silicon nitride, and silicon-on-insulator platforms.
• Develop and standardize integrated photonic spectrographs (IPS) with high spectral resolution (R > 100,000), wide bandwidth, and low insertion loss through collaboration between university researchers and commercial foundries.
• Improve coupling efficiency between telescope beams and single-mode waveguides using extreme adaptive optics (ExAO) systems to achieve Strehl ratios >90%, enabling diffraction-limited performance.
• Leverage existing commercial photonic design tools and fabrication foundries to reduce development time and cost, with a focus on creating a community-driven procurement pipeline for photonic components.
• Implement a phased technology development roadmap: 2–3 years for prototype IPS devices, 5–10 years for advanced design suites and custom component integration.
• Engage industry partners through targeted funding to transition key components (e.g., broadband couplers, tunable filters, low-loss waveguides) from lab-scale to commercial production, ensuring long-term sustainability.

Experimental results

Research questions

• RQ1 How can photonic technologies be adapted to meet the demanding spectral resolution and wavelength coverage requirements of next-generation astronomical spectrographs for ELTs and space missions?
• RQ2 What are the key technical and institutional barriers preventing widespread adoption of integrated photonics in astronomical instrumentation, and how can they be systematically addressed?
• RQ3 To what extent can existing telecom photonic platforms and fabrication processes be repurposed for astronomical applications with minimal re-engineering?
• RQ4 What level of investment is required to achieve flight-ready maturity for integrated photonic spectrographs, and how does this compare to the cost of traditional spectrograph systems?
• RQ5 How can a sustainable, scalable, and cost-effective supply chain for astronomical photonic components be established through public-private partnerships?

Key findings

• A $10 million investment over 5–10 years in integrated photonic spectrograph (IPS) development could enable the creation of high-performance, compact instruments suitable for both ground-based ELTs and space missions.
• Current extreme adaptive optics (ExAO) systems can achieve Strehl ratios of 90% or higher, enabling efficient coupling into single-mode waveguides and making high-resolution photonic spectroscopy feasible for ground-based telescopes.
• Multimode fibers serve as effective 'light buckets' for seeing-limited spectroscopy, but single-mode waveguides offer superior performance when combined with AO correction, enabling diffraction-limited operation.
• The cost of developing and qualifying photonic components is estimated at $10 million for IPS development and another $10 million for supporting technologies, representing a small fraction of the cost of a single ELT or space mission spectrograph.
• Commercial photonic foundries and design tools can be leveraged to accelerate development, but a dedicated community procurement process and close collaboration between academia and industry are essential for scalability.
• The success of GRAVITY at the VLTI—featuring four 8-m telescopes, four AO systems, and an integrated photonic beam combiner—demonstrates that bold, sustained investment in photonic technologies yields globally unrivaled scientific capabilities, providing a model for U.S. leadership in this domain.