Non-Hermitian Aspects of Coherently Coupled Vertical Cavity Laser Arrays

Gao, Zihe; Fryslie, Stewart T. M.; Thompson, Bradley J.; Dave, Harshil; Lakomy, Katherine; Carney, P. Scott; Choquette, Kent D.

doi:10.1364/cleo_si.2017.sw1c.4

Cited by 3 publications

(8 citation statements)

References 9 publications

(4 reference statements)

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“…Coupled mode theory was previously used to extract the complex coupling coefficient between the elements of a 2x1 VCSEL array [9]. We extend our analysis with a simple 1dimensional antiguided supermode model [10] and show the dominant lasing supermode should switch with increasing current injection.…”

Section: Introductionmentioning

confidence: 65%

“…The coupling between the array elements can be quantified using the complex coupling coefficient, 𝜅 = 𝜅 𝑟 + 𝑖𝜅 𝑖 . The real component, 𝜅 𝑟 expresses half the frequency splitting while the imaginary component, 𝜅 𝑖 represents half of the difference in gain between the in-phase and out-of-phase array supermodes [9]. As noted above, coherent emission into a supermode requires less gain than the individual cavity modes; thus, when the array operation is adjusted from two independent single element lasing modes to a coherent supermode, enhanced output power, Δ𝑃, is measured.…”

Section: A Complex Coupling Coefficientmentioning

confidence: 99%

“…Urbana, IL 61801 USA (e-mail: nusratj2@illinois.edu; wnorth2@illinois.edu; strzebo2@illinois.edu; choquett@illinois.edu) From the combined analysis of coupled mode theory and coupled rate equations, this system can be shown to be non-Hermitian [12] and exception point modes can be identified [13]. The strength of coupling can be quantified using a complex coupling coefficient [9]. This analysis shows that the imaginary component of the coupling coefficient corresponds to the modal gain difference between the supermodes, while the real component is related to the frequency difference between the supermodes.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Supermode Switching in Coherently-Coupled Vertical Cavity Surface Emitting Laser Diode Arrays

Jahan

North

Strzebonski

et al. 2022

IEEE J. Select. Topics Quantum Electron.

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We report and analyze the supermode switching with current injection found for coherently-coupled dual-element vertical cavity surface emitting laser arrays. The output power, spectral characteristics, and far-field mode profile are measured for a range of bias current operating conditions. The couplinginduced enhanced output power from an in-phase or out-of-phase supermode is confirmed when approximately equal currents are injected into each array element. We observe that the coherent supermode switches from out-of-phase to in-phase supermode with increasing equal current injection. The switching is found to be consistent with coupled mode theory and a 1-dimensional spatial supermode model. The calculated modal gain of the out-ofphase and in-phase array supermodes are consistent with the observed switching of the coherent supermodes.

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Section: Introductionmentioning

confidence: 65%

Section: A Complex Coupling Coefficientmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Supermode Switching in Coherently-Coupled Vertical Cavity Surface Emitting Laser Diode Arrays

Jahan

North

Strzebonski

et al. 2022

IEEE J. Select. Topics Quantum Electron.

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“…The photon-photon resonance frequency is related to the beating between the modal fields and can be related to the coupling coefficient. The coupling coefficient in temporal units [14]…”

Section: A Modes Coupling and Photon-photon Resonancementioning

confidence: 99%

“…The imaginary part of the coupling coefficient represents the gain difference between the elements, which dictates which of the nearly degenerate supermodes is dominant [5]. We recently reported a technique to experimentally measure both the real and imaginary components of the coupling coefficient using simultaneous measurements of output power, near-field intensity, and far-field profile [14,15]. In this work we will focus on a 2D waveguide model corresponding to 2×1 photonic crystal VCSEL array structures and evaluate the effects of a few key design parameters on the complex coupling coefficient.…”

Section: Introductionmentioning

confidence: 99%

Complex Waveguide Supermode Analysis of Coherently-Coupled Microcavity Laser Arrays

Strzebonski

Choquette

2022

IEEE J. Select. Topics Quantum Electron.

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Coherently coupled microcavity lasers have desirable properties for emerging applications. We use 2-dimensional complex refractive index waveguide modeling of 2-element photonic crystal vertical cavity surface emitting laser arrays to analyze their supermodes. The complex modal effective indices are used in turn to calculate the complex coupling coefficient between the laser array elements. An analysis of the effects of array design parameters, such as photonic crystal period, fillfactor, or confinement, to engineer the coupling coefficient for the desired properties is given and example designs for 850nm arrays are presented.

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Time-Delayed Reservoir Computing Based on a Two-Element Phased Laser Array for Image Identification

et al. 2021

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We report on a simple approach of time-delayed reservoir computing (RC) based on a two-element phased laser array for image identification. Here the phased laser array with optical feedback and injection is trained according to the representative characteristics extracted through histograms of oriented gradients. These characteristic vectors are multiplied by a random mask signal to form input data, which are subsequently trained in the reservoir. By optimizing the parameters of the RC, we achieve an identification accuracy of 97.44% on the MNIST dataset and 85.46% on the Fashion-MNIST dataset. These results indicate that our proposed RC indeed allows accurate classification of handwritten digit and fashion production. Moreover, we further forecast an RC scheme based on a larger-scale phased laser array, which is expected to tackle more complex tasks at a high speed. Our work offers a possibility for advanced image processing using highly integrated neuromorphic photonic systems.

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Non-Hermitian Aspects of Coherently Coupled Vertical Cavity Laser Arrays

Cited by 3 publications

References 9 publications

Supermode Switching in Coherently-Coupled Vertical Cavity Surface Emitting Laser Diode Arrays

Supermode Switching in Coherently-Coupled Vertical Cavity Surface Emitting Laser Diode Arrays

Complex Waveguide Supermode Analysis of Coherently-Coupled Microcavity Laser Arrays

Time-Delayed Reservoir Computing Based on a Two-Element Phased Laser Array for Image Identification

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