High resolution spectral metrology leveraging topologically enhanced optical activity in fibers

Greenberg, Aaron P.; Prabhakar, Gautam; Ramachandran, Siddharth

doi:10.1038/s41467-020-18931-6

Cited by 23 publications

(5 citation statements)

References 47 publications

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“…Beyond SDM/MDM fiber-optic communications using spatial modes, more extended applications of versatile mode bases in fibers are expected, such as spin–orbit mapping, 62 optical activity, 63 nonlinear optics, 64 optical metrology, 65 optical imaging, 66 and quantum science 67 , 68 . For example, spin–orbit mapping of light in an FMF originating from the mode degeneracy lifting, high-resolution wave meter by enhanced optical activity in fibers, intermodal nonlinear mixing with Bessel beams in fibers, remote measurement of the angular velocity vector based on vectorial Doppler effect using ACF, time-of-flight 3D imaging through multimode optical fibers, and high-dimensional quantum cryptography with hybrid OAM states through RCF have been proposed and demonstrated, showing favorable performance.…”

Section: Discussionmentioning

confidence: 99%

Finding the superior mode basis for mode-division multiplexing: a comparison of spatial modes in air-core fiber

Wang,

Ai,

et al. 2023

Adv. Photon.

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Diverse spatial mode bases can be exploited in mode-division multiplexing (MDM) to sustain the capacity growth in fiber-optic communications, such as linearly polarized (LP) modes, vector modes, LP orbital angular momentum (LP-OAM) modes, and circularly polarized OAM (CP-OAM) modes. Nevertheless, which kind of mode bases is more appropriate to be utilized in fiber still remains unclear. Here, we aim to find the superior mode basis in MDM fiber-optic communications via a system-level comparison in air-core fiber (ACF). We first investigate the walk-off effect of four spatial mode bases over 1-km ACF, where LP and LP-OAM modes show intrinsic mode walk-off, while it is negligible for vector and CP-OAM modes. We then study the mode coupling effect of degenerate vector and CP-OAM modes over 1-km ACF under fiber perturbations, where degenerate even and odd vector modes suffer severe mode cross talk, while negligible for highorder degenerate CP-OAM modes based on the laws of angular momentum conservation. Moreover, we comprehensively evaluate the system-level performance for data-carrying single-channel and two-channel MDM transmission with different spatial mode bases under various kinds of fiber perturbations (bending, twisting, pressing, winding, and out-of-plane moving). The obtained results indicate that the CP-OAM mode basis shows superiority compared to other mode bases in MDM fiber-optic communications without using multiple-input multiple-output digital signal processing. Our findings may pave the way for robust shortreach MDM optical interconnects for data centers and high-performance computing.

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Section: Discussionmentioning

confidence: 99%

Finding the superior mode basis for mode-division multiplexing: a comparison of spatial modes in air-core fiber

Wang,

Ai,

et al. 2023

Adv. Photon.

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“…S7, A and B), suggest that transmission in TCMs may be helpful in managing nonlinear signal distortions ( 28 , 29 ) in telecommunications applications. In addition, a plethora of low-cross-talk modes potentially enables low cross-talk per superpositions of modes as well ( 30 ), as required for quantum transport, effectively allowing high-dimensional encoding ( 2 ) and sources through intermodal interaction ( 31 ). Average losses for TCMs (~5.0 dB/km) and for TIR bound modes (~1.4 dB/km) are, at their current maturity, reasonable for amplifier and inter–data center applications, but because confinement losses are predicted to be much lower, manufacturing optimizations (fig.…”

Section: Fiber Properties and Transmission Characteristicsmentioning

confidence: 99%

Scaling information pathways in optical fibers by topological confinement

Kristensen

Ramachandran

2023

Science

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Spatial mode-count scalability in optical fibers is of paramount importance for addressing the upcoming information-capacity crunch, reducing energy consumption per bit, and for enabling advanced quantum computing networks, but this scalability is severely limited by perturbative mode mixing. We show an alternative means of light guidance, in which light’s orbital angular momentum creates a centrifugal barrier for itself, thereby enabling low-loss transmission of light in a conventionally forbidden regime wherein the mode mixing can be naturally curtailed. This enables kilometer-length-scale transmission of a record ~50 low-loss modes with cross-talk as low as −45 decibels/kilometer and mode areas of ~800 square micrometers over a 130-nanometer telecommunications spectral window. This distinctive light-guidance regime promises to substantially increase the information content per photon for quantum or classical networks.

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“…Therefore, the best way to study the strong SOI or geometric phase in strongly confining fibers is to show the spin-dependent modal propagation splitting, instead of the polarization or pattern rotation of light. There are two reports, as the transition between these two cases, where the weakly modal propagation splitting is used for studying the SOI of light by observing mode rotation in a specific vortex fiber [37], or exploit its wavelengthdependence (dispersion property) to achieve a high resolution spectral metrology [65].…”

Section: Topologically Spin-dependent Walking Off Induced By Transver...mentioning

confidence: 99%

From Imbert–Fedorov shift to topologically spin-dependent walking off for highly confining fiber-guided twisted light

Fang¹,

Wang²

2021

J. Opt.

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Light–matter interaction at dielectric interfaces usually manifests as spin-dependent correction to light propagation, known as classical Imbert–Fedorov (IF) shift or photonic spin Hall effect, ruled by the general spin–orbit interaction (SOI) of light. Even though vector wave equations and strong SOI-based perturbation theory in a wave picture can offer good solutions to describe the modal dispersion in optical fibers, it is difficult for all these to provide an intuitive insight into the walking off for twisted (or vortex) light beams carrying orbital angular momentum (OAM). Here we present a new perspective to the topologically spin-dependent modal splitting for the twisted light highly confined in optical fibers based on the classical IF shift on geometric optics. We verify this topologically IF-shift-based walking off by comparing the analytical results of modal splitting degrees with the solutions of eigen equation, and associate the longitudinal projection of IF shift with an interesting resonance of fiber Bragg gratings locked by the signs of SAM or OAM. This interpretation provides an insight supplement to describe light ray propagating in optical fibers together with both longitudinal Goos–Hänchen and transverse IF shift under the total internal reflection, and may benefit the development of nanoscale fiber-based light on optically classical or quantum communication and metrology.

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High resolution spectral metrology leveraging topologically enhanced optical activity in fibers

Cited by 23 publications

References 47 publications

Finding the superior mode basis for mode-division multiplexing: a comparison of spatial modes in air-core fiber

Finding the superior mode basis for mode-division multiplexing: a comparison of spatial modes in air-core fiber

Scaling information pathways in optical fibers by topological confinement

From Imbert–Fedorov shift to topologically spin-dependent walking off for highly confining fiber-guided twisted light

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