Midinfrared broadband achromatic astronomical beam combiner for nulling interferometry

Hsiao, Hsien Kai; Winick, Kim A.; Monnier, John D.

doi:10.1364/ao.49.006675

Cited by 18 publications

(13 citation statements)

References 22 publications

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“…A tricoupler is fundamentally a device that makes a unitary transform between three electric fields to another three electric fields. We are considering primarily a situation where it is used as a beam combiner with two input beams (with no light injected into the third input) 17 and not as a beam splitter 15 . There are only certain design transformations that are possible.…”

Section: Theoretical Developmentmentioning

confidence: 99%

Interferometric Beam Combination with a Triangular Tricoupler Photonic Chip

Hansen,

Ireland,

Ross-Adams

et al. 2021

Preprint

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Beam combiners are important components of an optical/infrared astrophysical interferometer, with many variants as to how to optimally combine two or more beams of light to fringe-track and obtain the complex fringe visibility. One such method is the use of an integrated optics chip that can instantaneously provide the measurement of the visibility without temporal or spatial modulation of the optical path. Current asymmetric planar designs are complex, resulting in a throughput penalty, and so here we present developments into a three dimensional triangular tricoupler that can provide the required interferometric information with a simple design and only three outputs. Such a beam combiner is planned to be integrated into the upcoming Pyxis interferometer, where it can serve as a high-throughput beam combiner with a low size footprint. Results into the characterisation of such a coupler are presented, highlighting a throughput of 89±11% and a flux splitting ratio between 33:33:33 and 52:31:17 over a 20% bandpass. We also show the response of the chip to changes in optical path, obtaining an instantaneous complex visibility and group delay estimate at each input delay.

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Section: Theoretical Developmentmentioning

confidence: 99%

Interferometric Beam Combination with a Triangular Tricoupler Photonic Chip

Hansen,

Ireland,

Ross-Adams

et al. 2021

Preprint

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“…It is found that the most efficient taper is obtained if θ(z) varies as a Blackman function [28]. We let…”

Section: Advanced Adiabatic Couplermentioning

confidence: 99%

“…The maximum dephasing ∆β max occurs at the positions z = 0 and z = L, where we choose W Gap (0) = W Gap (L) = 850 nm, W Si (0) = 280 nm and W Si (L) = 310 nm to assure complete decoupling between both WGs. It is found that the most efficient taper is obtained if θ(z) varies as a Blackman function [28]. We let…”

Section: Advanced Adiabatic Couplermentioning

confidence: 99%

Novel adiabatic coupler for III-V nano-ridge laser grown on a Si photonics platform

Shi¹,

Kunert²,

Koninck³

et al. 2019

Opt. Express

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While III-V lasers epitaxially grown on silicon have been demonstrated, an efficient approach for coupling them with a silicon photonics platform is still missing. In this paper, we present a novel design of an adiabatic coupler for interfacing nanometer-scale III-V lasers grown on SOI with other silicon photonics components. The starting point is a directional coupler, which achieves 100% coupling efficiency from the III-V lasing mode to the Si waveguide TE-like ground mode. To improve the robustness and manufacturability of the coupler, a linear-tapered adiabatic coupler is designed, which is less sensitive to variations and still reaches a coupling efficiency of around 98%. Nevertheless, it has a relatively large footprint and exhibits some undesired residual coupling to TM-like modes. To improve this, a more advanced adiabatic coupler whose geometry is varied along its propagation length is designed and manages to reach ∼100% coupling and decoupling within a length of 200 µm. The proposed couplers are designed for the particular case of III-V nano-ridge lasers monolithically grown using aspect-ratio-trapping (ART) together with nano-ridge engineering (NRE) but are believed to be compatible with other epitaxial III-V/Si integration platforms recently proposed. In this way, the presented coupler is expected to pave the way to integrating III-V lasers monolithically grown on SOI wafers with other photonics components, one step closer towards a fully functional silicon photonics platform. micrometers, complicating the coupling process. Alternatively, several groups have demonstrated that it is possible to suppress defect formation by growing the III-V materials within a narrow opening defined in a SiO 2 mask deposited on the silicon substrate [11,15,16,19,20]. In this case the extent of the III-V structure can be considerably smaller and coupling to a waveguide directly defined in the substrate becomes feasible. E.g. L. Megalini et al. from UCSB demonstrated the growth of an InGaAsP MQW structure on a V-groove-patterned SOI substrate with its QWs ∼ 500 nm away from the Si layer [16]. Y. Han et al. recently demonstrated a nanolaser array emitting at telecom wavelengths grown on SOI, with InGaAs QWs ∼ 300 nm separated from the Si layer [15], while M. Wang et al have shown the growth of InGaAs/InP nanowires on an SOI substrate with the QWs ∼ 500 nm away from the Si layer [19]. Z. Wang et al. demonstrated single-mode lasing of ∼ 500 nm high InP nanowires grown on a Si substrate [11]. Also our previously demonstrated nano-ridge laser [20] (see Fig. 1(a)) with the active layer ∼ 600 nm above the Si substrates fits this scheme. Therefore, in this paper we develop a method to design couplers that allow to integrate this type of sub-micrometer scale lasers with silicon waveguides defined in the same substrate. A simple butt-coupling approach whereby the waveguide is placed in line with the laser cavity is thereby not desired as the selective area growth process often results in irregularly shaped facets as shown in Fig. 1...

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“…• Nuller design for exoplanet detections at K, L bands. This will impact arrangement of telescopes within 1.2 km baselines to optimize clever nulling schemes (e.g., Hsiao et al, 33 Lacour et al, 34 Martinache & Ireland 35 ). Table 3 contains information on two reference facility architectures for PFI, one is a 12×3 m array and the other a 12 × 8 m array.…”

Section: Reference Pfi Facility Architecture(s)mentioning

confidence: 99%

Planet formation imager: project update

Ireland

Kraus

Alonso‐Herrero

et al. 2018

Optical and Infrared Interferometry and Imaging VI

Self Cite

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The Planet Formation Imager (PFI) is a near-and mid-infrared interferometer project with the driving science goal of imaging directly the key stages of planet formation, including the young proto-planets themselves. Here, we will present an update on the work of the Science Working Group (SWG), including new simulations of dust structures during the assembly phase of planet formation and quantitative detection efficiencies for accreting and non-accreting young exoplanets as a function of mass and age. We use these results to motivate two reference PFI designs consisting of a) twelve 3 m telescopes with a maximum baseline of 1.2 km focused on young exoplanet imaging and b) twelve 8 m telescopes optimized for a wider range of young exoplanets and protoplanetary disk imaging out to the 150 K H 2 O ice line. Armed with 4 × 8 m telescopes, the ESO/VLTI can already detect young exoplanets in principle and projects such as MATISSE, Hi-5 and Heimdallr are important PFI pathfinders to make this possible. We also discuss the state of technology development needed to make

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Midinfrared broadband achromatic astronomical beam combiner for nulling interferometry

Cited by 18 publications

References 22 publications

Interferometric Beam Combination with a Triangular Tricoupler Photonic Chip

Interferometric Beam Combination with a Triangular Tricoupler Photonic Chip

Novel adiabatic coupler for III-V nano-ridge laser grown on a Si photonics platform

Planet formation imager: project update

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