Laguerre-Gaussian mode expansion for arbitrary optical fields using a subspace projection method

Xiao, Yu; Tang, Xiahui; Wan, Chenhao; Qin, Yingxiong; Peng, Hao; Hu, Cong; Qin, Beilun

doi:10.1364/ol.44.001615

Cited by 14 publications

(8 citation statements)

References 14 publications

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“…Besides, the doughnut-like modes propagate stably in free space without changing their intensity distribution, so they are considered to be a superposition of the fundamental Gaussian mode and higher-order Laguerre-Gaussian modes [29] . Moreover, the reduction of central intensity means the decrease in the proportion of the fundamental Gussian mode [30] . Thus, a new degree of freedom for customizing the positive refractive index profile of FLDW waveguides at sub-micron resolution is demonstrated for on-chip mode conversion applications.…”

Section: Resultsmentioning

confidence: 99%

Photonic lattice-like waveguides in glass directly written by femtosecond laser for on-chip mode conversion

Wang¹,

Zhong

Chen

et al. 2022

Chin. Opt. Lett.

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We report on a conceptually new type of waveguide in glass by femtosecond laser direct writing, namely, photonic latticelike waveguide (PLLW). The PLLW's core consists of well-distributed and densified tracks with a sub-micron size of 0.62 μm in width. Specifically, a PLLW inscribed as hexagonal-shape input with a ring-shape output side was implemented to converse Gaussian mode to doughnut-like mode, and high conversion efficiency was obtained with a low insertion loss of 1.65 dB at 976 nm. This work provides a new freedom for design and fabrication of the refractive index profile of waveguides with sub-micron resolution and broadens the functionalities and application scenarios of femtosecond laser direct-writing waveguides in future 3D integrated photonic systems.

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Section: Resultsmentioning

confidence: 99%

Photonic lattice-like waveguides in glass directly written by femtosecond laser for on-chip mode conversion

Wang¹,

Zhong

Chen

et al. 2022

Chin. Opt. Lett.

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“…The coupling ratio is determined by the ratio of the integral intensities of the fundamental mode waveguide and the higher-order-mode waveguide. The mode extinction ratio, defined as the power ratio of the fundamental mode and LP 11 mode, is numerically calculated from the mode field distribution using the mode decomposition method 74 .…”

Section: Methodsmentioning

confidence: 99%

Precise mode control of laser-written waveguides for broadband, low-dispersion 3D integrated optics

Wang,

Zhong,

Lau

et al. 2024

Light Sci Appl

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Three-dimensional (3D) glass chips are promising waveguide platforms for building hybrid 3D photonic circuits due to their 3D topological capabilities, large transparent windows, and low coupling dispersion. At present, the key challenge in scaling down a benchtop optical system to a glass chip is the lack of precise methods for controlling the mode field and optical coupling of 3D waveguide circuits. Here, we propose an overlap-controlled multi-scan (OCMS) method based on laser-direct lithography that allows customizing the refractive index profile of 3D waveguides with high spatial precision in a variety of glasses. On the basis of this method, we achieve variable mode-field distribution, robust and broadband coupling, and thereby demonstrate dispersionless LP21-mode conversion of supercontinuum pulses with the largest deviation of <0.1 dB in coupling ratios on 210 nm broadband. This approach provides a route to achieve ultra-broadband and low-dispersion coupling in 3D photonic circuits, with overwhelming advantages over conventional planar waveguide-optic platforms for on-chip transmission and manipulation of ultrashort laser pulses and broadband supercontinuum.

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“…For the current implementation of the GBD in IfoCAD, the parameters that can be chosen explicitly are the waist scaling factor f ws , the number g of grid beams along each primary axis of the square grid, and the window size L. The waist radius w 0g of the grid beams and grid distance d g are then determined using Equation (24). Therefore, there are three parameters that influence the precision of the decomposition, among which the onedimensional number g of grid beams roughly compares with the mode order N of the MEM.…”

Section: Gbd Settingsmentioning

confidence: 99%

“…It is also known as modal decomposition [20] or truncated orthogonal-series expansion [21]. If Laguerre-Gaussian modes are used for the decomposition, the method is referred to as the Laguerre-Gauss expansion [22], Laguerre-Gaussian series expansion method [23], or Laguerre-Gaussian mode decomposition [24], and if Hermite-Gaussian modes are used, it is referred to as the truncated Hermite-Gauss series expansion [25].…”

Section: Introductionmentioning

confidence: 99%

Method Comparison for Simulating Non-Gaussian Beams and Diffraction for Precision Interferometry

Zhao,

Tao,

Weber

et al. 2023

Sensors

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In the context of simulating precision laser interferometers, we use several examples to compare two wavefront decomposition methods—the Mode Expansion Method (MEM) and the Gaussian Beam Decomposition (GBD) method—for their precision and applicability. To assess the performance of these methods, we define different types of errors and study their properties. We specify how the two methods can be fairly compared and based on that, compare the quality of the MEM and GBD through several examples. Here, we test cases for which analytic results are available, i.e., non-clipped circular and general astigmatic Gaussian beams, as well as clipped circular Gaussian beams, in the near, far, and extremely far fields of millions of kilometers occurring in space-gravitational wave detectors. Additionally, we compare the methods for aberrated wavefronts and their interaction with optical components by testing reflections from differently curved mirrors. We find that both methods can generally be used for decomposing non-Gaussian beams. However, which method is more accurate depends on the optical system and simulation settings. In the given examples, the MEM more accurately describes non-clipped Gaussian beams, whereas for clipped Gaussian beams and the interaction with surfaces, the GBD is more precise.

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Laguerre-Gaussian mode expansion for arbitrary optical fields using a subspace projection method

Cited by 14 publications

References 14 publications

Photonic lattice-like waveguides in glass directly written by femtosecond laser for on-chip mode conversion

Photonic lattice-like waveguides in glass directly written by femtosecond laser for on-chip mode conversion

Precise mode control of laser-written waveguides for broadband, low-dispersion 3D integrated optics

Method Comparison for Simulating Non-Gaussian Beams and Diffraction for Precision Interferometry

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