Fabrication of precise aperiodic multichannel fibre Bragg grating filters for spectral line suppression in hydrogenated standard telecommunications fibre

Gbadebo, Adenowo; Turitsyna, Elena G.; Williams, J.A.R.

doi:10.1364/oe.26.001315

Cited by 6 publications

(4 citation statements)

References 31 publications

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“…In particular it is possible with modern aperiodic grating designs to obtain an excellent match even for complicated sets of irregularly spaced atomic or molecular lines. Such bespoke gratings may be tailored to target gas species with high specificity [395] and can be fabricated from the visible through the NIR. Such an optic may be integrated into a working sensor system [396] by imposing a variable filter velocity response (potentially by way of a fiber stretcher, or tuning the response with temperature), and ideally facilitates recovery of both the reflected and transmitted beams to optimize capability for accurate calibration.…”

Section: Fbgsmentioning

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: Fbgsmentioning

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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“…For CWBG in this work, the most promising method might be adopting a weaker grating design. Note that even if the target spectrum is unchanged, we can still decrease the maximum grating strength by introducing different group delay terms for different notches doi: 10.1109/JLT.2020.2992758 © 2020 IEEE Accepted for publication in Journal of Lightwave Technology [18]. It will stretch the pulse response h in time and lead to a longer grating in space, which needs to be considered as a trade-off factor in practice.…”

Section: A Effect From Cladding Mode Couplingmentioning

confidence: 99%

“…This type of filter is featured by its large spectral range, high rejection ratio and narrow notch width, which up to now is best achieved with complex Bragg gratings. Several studies have been carried out using FBGs to achieve this type of filter [9], [12], [16]- [18]. With the rapid advancements of various chip-based fabrication techniques, many exciting works have been done with integrated Bragg gratings [19]- [21].…”

Section: Introductionmentioning

confidence: 99%

Integrated Arbitrary Filter With Spiral Gratings: Design and Characterization

Xie

Zhan

et al. 2020

J. Lightwave Technol.

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We report the design and characterization of a high performance integrated arbitrary filter from 1450 nm to 1640 nm. The filter's target spectrum is chosen to suppress the night-sky OH emission lines, which is critical for ground-based astronomical telescopes. This type of filter is featured by its large spectral range, high rejection ratio and narrow notch width. Traditionally it is only successfully accomplished with fiber Bragg gratings. The technique we demonstrate here is proven to be very efficient for on-chip platforms, which can bring many benefits for device footprint, performance and cost. For the design part, two inverse scattering algorithms are compared, the frequency domain discrete layer-peeling (f-DLP) and the time domain discrete layer-peeling (t-DLP). f-DLP is found to be superior for the grating reconstruction in terms of accuracy and robustness. A method is proposed to resolve the non-uniformity issue caused by the non-zero layer size in the DLP algorithm. The designed 55-notch filter is 50-mm-long and implemented on a compact Si 3 N 4 /SiO 2 spiral waveguide with a total length of 63 mm. Experimentally, we demonstrate that the device has a insertion loss as low as 2.5 dB, and that the waveguide propagation loss is as low as 0.10 dB/cm. We are also able to achieve uniform notch depths and 3-dB widths of about 28 dB and 0.22 nm, respectively. a denotes the widths of narrow -wide part of a simple Bragg grating. sign for the R&D of large-scale photonic circuits with increasing flexibility and complexity.

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“…Simple or complex gratings can be fabricated through point-by-point (PbP) [10] or line-by-line (LbL) [11] inscription process using femtosecond lasers and de-phasing methods [12]. Ultra-long gratings have been fabricated using electro-optic modulators (EOMs) [13] in push-pull configuration, and complex OH filters have been fabricated using acousto-optic modulators (AOMs) [14]. E-or A-OMS fabrication techniques generate a "runninginterference"pattern, similar to a rack-and-pinion, that is synchronised with the velocity of optical fiber, requiring precise control on the intensity, focus spot size, and velocity over a long length in real time.…”

Section: Introductionmentioning

confidence: 99%

Aperiodic phase masks for inscribing complex multi-notch OH-emission filters for astronomy

Madhav,

Zhang,

Roth

2018

Preprint

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We demonstrate for the first time, a new type of aperiodic phase mask (APM) for fabricating multi-channel aperiodic fiber Bragg gratings. The mask is made of individual diffraction phase gratings with discrete unequal phase-steps incorporated at periodic locations. The diffraction at the discrete phase-steps in the phase mask produces corresponding half phase-steps at periodic locations along the fiber. The accumulated phase, along with index modulation, generates the desired multinotch reflection spectrum. Complex fiber Bragg grating filters fabricated using APM, in a standard phase mask based fabrication setup, can be used to simultaneously suppress multiple aperiodic OH emission wavelengths in near infrared (NIR) existing in upper atmosphere, and increase the sensitivity of ground based telescopes.

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Fabrication of precise aperiodic multichannel fibre Bragg grating filters for spectral line suppression in hydrogenated standard telecommunications fibre

Cited by 6 publications

References 31 publications

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

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

Integrated Arbitrary Filter With Spiral Gratings: Design and Characterization

Aperiodic phase masks for inscribing complex multi-notch OH-emission filters for astronomy

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