Broadband 2  ×  2 multimode interference coupler for mid-infrared wavelengths

Stirling, Callum J.; Halir, Robert; Sánchez‐Postigo, Alejandro; Qu, Zhibo; Reynolds, Jamie D.; Penadés, Jordi Soler; Murugan, Ganapathy Senthil; Ortega‐Moñux, Alejandro; Wangüemert‐Pérez, J. Gonzalo; Molina-Fernández, Í.; Mashanovich, Goran Z.; Nedeljkovic, Milos

doi:10.1364/ol.439985

Cited by 10 publications

(2 citation statements)

References 32 publications

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“…For our application in MIR absorption spectroscopy, spectrometers based on Mach-Zehnder interferometers require three main components for broadband operation: single-mode waveguides, broadband splitters, and optical delay lines. As above, the ESM waveguides provide broadband single-mode operation and we have previously demonstrated broadband splitters at similar wavelengths [5,6]. The new bend designs allow waveguide layouts for the delay lines, through circuit designs such as box spirals (consisting of 90° bends and straight waveguides).…”

Section: Discussionmentioning

confidence: 82%

Mid-infrared waveguides for broadband single-moded guidance

Stirling

Logan

Cao

et al. 2023

Integrated Optics: Design, Devices, Systems and Applications VII

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We present the development of SOI waveguides with low-loss (~1.5 dB/cm) single-moded guidance over an octave of frequency. Broadband single-moded guidance is needed for on-chip mid-infrared spectroscopy and this cannot be provided by conventional waveguide geometries in standard material platforms. The reported waveguides require a simple fabrication process flow and will be widely applicable to different mid-infrared wavelength bands for a variety of sensing applications. We further present a low-loss bend design (0.179 ± 0.031 dB/90°) that overcomes the inherently large bending loss of the waveguides, which is a limiting factor in the utility of the waveguides. We consider different prospective designs for the use of these waveguides in a circuit for a sensing device.

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Section: Discussionmentioning

confidence: 82%

Mid-infrared waveguides for broadband single-moded guidance

Stirling

Logan

Cao

et al. 2023

Integrated Optics: Design, Devices, Systems and Applications VII

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“…To make broadband MMIs, a more complex design is required than those typically used as standard for telecommunication applications. The internal wavelength-dependency can be compensated for by creating a non-uniform effective refractive index inside the MM waveguide [567], either by changing the width of the MMI along the propagation direction, or by inserting more complex structures inside the cavity. The use of sub-wavelength grating structures inside the MMI has been shown to greatly increase the operating bandpass [568], and recent development in inverse design using deep neural networks makes the design of these complex structures far easier to derive [569].…”

Section: Advances In Science and Technology To Meet 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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