Environmental characterisation and stabilisation of a 2×200-meter outdoor fibre interferometer at the CHARA Array

Lehmann, Lucien; Delage, Laurent; Grossard, Ludovic; Reynaud, François; Golden, Steve; Woods, Craig; Webster, Leslie T.; Sturmann, J.; Brummelaar, T. ten

doi:10.1007/s10686-019-09627-x

Cited by 12 publications

(9 citation statements)

References 11 publications

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“…Although fibers offer clear simplifications over distance, they add challenges due to their intrinsic properties (table 3)-material absorption, chromatic dispersion [525][526][527][528][529][530], polarization birefringence, and thermal and vibration induced OPD [531,532]. Fibers are dispersive media, and dispersion due to fiber length mismatch, and fiber bending/stretching causes arbitrary phase delay as a function of the wavelength, which leads to a shift in the zero-order fringes and effectively loss of fringe visibility for broadband operation [525].…”

Section: Current and Future Challengesmentioning

confidence: 99%

2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments

Jovanovic,

Gatkine,

Anugu

et al. 2023

J. Phys. Photonics

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Photonic technologies offer numerous functionalities that can be used to realize astrophotonic instruments. The most spectacular example to date is the ESO Gravity instrument at the Very Large Telescope in Chile that combines the light-gathering power of four 8-m telescopes through a complex photonic interferometer. Fully integrated astrophotonic devices offer critical advantages for instrument development, including extreme miniaturization when operating at the diffraction-limit, plus integration, superior thermal and mechanical stabilization owing to the small footprint, and high replicability offering significant cost savings. Numerous astrophotonic technologies have been developed to address shortcomings of conventional instruments to date, including the development of photonic lanterns to convert from multimode inputs to single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the atmosphere, beam combiners enabling long baseline interferometry with for example, ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers. Despite these successes, the facility implementation of photonic solutions in astronomical instrumentation is currently limited because of 1) low throughputs from coupling to fibers, coupling fibers to chips, propagation and bend losses, device losses, etc., 2) difficulties with scaling to large channel count devices needed for large bandwidths and high resolutions, and 3) efficient integration of photonics with detectors. In this roadmap, we identify 23 key areas that need further development. We outline the challenges and advances needed across those areas covering design tools, simulation capabilities, fabrication processes, the need for entirely new components, integration and hybridization and the characterization of devices. To realize these advances the astrophotonics community will have to work cooperatively with industrial partners who have more advanced manufacturing capabilities. With the advances described herein, multi-functional integrated instruments will be realized leading to novel observing capabilities for both ground and space based platforms, enabling new scientific studies and discoveries.

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Section: Current and Future Challengesmentioning

confidence: 99%

2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments

Jovanovic,

Gatkine,

Anugu

et al. 2023

J. Phys. Photonics

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“…Another noticeable example regards the recent implementation of hectometric fiber links between the CHARA telescopes to support accurate stabilization of the optical path difference down to 4 nm rms using stretchers of polarization-maintaining fibers operating at 1550 nm. 32 At wavelengths longer than 2.2 µm, the situation appears less mature. Mid-infrared fluoride-based solid-core fibers are now commercially available on the market, but with poorer performance than the silica-based counterparts.…”

Section: Beam Transportmentioning

confidence: 99%

A report on the status of astrophotonics for optical/IR interferometry and beyond

Labadie

2022

Optical and Infrared Interferometry and Imaging VIII

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Long-baseline interferometry and high-resolution spectroscopy are two examples of areas that have benefited from astrophotonics devices, but the application range is expanding to other subareas and other wavelength ranges.The VLTI has been one of the pioneering astronomical infrastructure to exploit the potential of astrophotonics instrumentation for high-angular resolution interferometric observations, whereas new opportunities will arise in the context of the future ELTs. In this contribution, I review the current state of the art regarding the interplay between photonic-based solutions and astronomical instrumentation and highlight the growth of the field, as well as its recognition in recent strategy surveys such as the Decadal. I will explain the benefits of different technological platforms making use of photolithography or laser-writing techniques. I will review the most recent results in the field covering simulations, laboratory characterization and on-sky prototyping. Astrophotonics may have a unique role to play in the forthcoming era of new ground-based astronomical facilities, and possibly in the field of space science.

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“…Subsequent experiments with 20 cm telescopes connected with a pair of 300 m-long silica fibers showed the possibility to obtain fringes on bright stars in J and H band, but pointed out the need for an active compensation system for the acoustic noise picked up by the fibers (Woillez et al 2017). More recently (Lehmann et al 2019), an actively stabilized 200?200 m fiber interferometer operating at telecom wavelength (1550 nm) was laid over the 160 m-long path outdoors between one of the CHARA telescopes and the beam-combination facility on Mt. Wilson.…”

Section: High-angular Resolutionmentioning

confidence: 99%

“…This is indeed the basic concept that the project ALOHA aims to test at the CHARA interferometric array (Lehmann et al 2018b). The project aims at enabling MIR interferometric observations by converting MIR photons to the telecom wavelengths by means of a PPLN waveguide and transferring the up-converted light to the beam combiner using hectometric single-mode optical fibers (Lehmann et al 2019). As the efficient conversion of photons requires long lithium niobate waveguides (2-4 cm), the conversion bandwidth is small and only narrow lines of the MIR spectrum can be explored.…”

Section: Detection Enhancement Through Frequency Conversionmentioning

confidence: 99%

Astrophotonics: astronomy and modern optics

Minardi¹,

Harris

Labadie

2021

Astron Astrophys Rev

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Much of the progress in astronomy has been driven by instrumental developments, from the first telescopes to fiber fed spectrographs. In this review, we describe the field of astrophotonics, a combination of photonics and astronomical instrumentation that is gaining importance in the development of current and future instrumentation. We begin with the science cases that have been identified as possibly benefiting from astrophotonic devices. We then discuss devices, methods and developments in the field along with the advantages they provide. We conclude by describing possible future perspectives in the field and their influence on astronomy.

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Environmental characterisation and stabilisation of a 2×200-meter outdoor fibre interferometer at the CHARA Array

Cited by 12 publications

References 11 publications

2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments

2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments

A report on the status of astrophotonics for optical/IR interferometry and beyond

Astrophotonics: astronomy and modern optics

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