We demonstrate a method for fabricating sapphire rib waveguides with femtosecond laser micromachining technology. Finite difference beam propagation method(FD-BPM) is applied to design sapphire rib waveguides. We expl...
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We demonstrate a method for fabricating sapphire rib waveguides with femtosecond laser micromachining technology. Finite difference beam propagation method(FD-BPM) is applied to design sapphire rib waveguides. We explore the process of etching on a sapphire substrate surface via direct laser ablation. Rib waveguides that satisfies the dimensions of our design were fabricated. Actual light propagation performance is tested, and with the cut-back method, the insertion loss of 2.9±0.5 dB/cm is measured.
We analyze the properties of femtosecond-laser-written waveguides in silicon. By using a mix of semianalytical and numerical methods, we find that the transverse index profile is accurately modeled by a W-shaped funct...
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We analyze the properties of femtosecond-laser-written waveguides in silicon. By using a mix of semianalytical and numerical methods, we find that the transverse index profile is accurately modeled by a W-shaped function supporting nonleaky guided modes. The maximum change in the refractive index is about 4×10−3, whereas the central lobe is about 2.5 μm wide for a writing wavelength of 1.55 μm. Waveguide shape and maximum index variation both saturate for input pulse energies larger than 100 nJ and a pulse duration of 860 fs. We find that the performance of the waveguides are limited by the presence of randomly distributed scattering centers situated in the waveguide core. To confirm our findings, we probed the waveguide response as the input beam is kept normal at the input interface but shifted perpendicularly to the waveguide axis, resulting in a variable offset with respect to the center of the waveguide. The behavior of the energy coupled in the waveguide versus the beam shift is in agreement with theoretical predictions. We also used a simple analytical model to describe the nonlinear propagation of the writing beam.
We demonstrate nonlinear optical effects and self-trapping of a laser beam through red blood cell suspensions under different osmotic conditions. Formed waveguides can provide effective guidance for weaker light throu...
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We present a method for efficient spin-wave guiding within the magnonic nanostructures. Our technique is based on the anomalous refraction in the metamaterial flat slab. The gradual change of the material parameters (...
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We present a method for efficient spin-wave guiding within the magnonic nanostructures. Our technique is based on the anomalous refraction in the metamaterial flat slab. The gradual change of the material parameters (saturation magnetization or magnetic anisotropy) across the slab allows tilting the wavefronts of the transmitted spin waves and controlling the refraction. Numerical studies of the spin-wave refraction are preceded by the analytical calculations of the phase shift acquired by the spin wave due to the change of material parameters in a confined area. We demonstrate that our findings can be used to guide the spin waves smoothly in curved waveguides, even through sharp bends, without reflection and scattering between different waveguide’s modes, preserving the phase, the quantity essential for wave computing.
We demonstrate a new highly tunable technique for generating meter-scale low density plasma waveguides. Such guides can enable laser-driven electron acceleration to tens of GeV in a single stage. Plasma waveguides are...
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We demonstrate a new highly tunable technique for generating meter-scale low density plasma waveguides. Such guides can enable laser-driven electron acceleration to tens of GeV in a single stage. Plasma waveguides are imprinted in hydrogen gas by optical field ionization induced by two time-separated Bessel beam pulses: The first pulse, a J0 beam, generates the core of the waveguide, while the delayed second pulse, here a J8 or J16 beam, generates the waveguide cladding, enabling wide control of the guide’s density, depth, and mode confinement. We demonstrate guiding of intense laser pulses over hundreds of Rayleigh lengths with on-axis plasma densities as low as Ne0∼5×1016 cm−3.
We report ultra-low propagation losses in silicon sub-micrometric waveguides on a 200 mm CMOS compatible photonics platform. We show median losses in C-band (O-band) as low as 0.1 dB/cm and 0.7 dB/cm (0.14 dB/cm and 1...
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We report ultra-low propagation losses in silicon sub-micrometric waveguides on a 200 mm CMOS compatible photonics platform. We show median losses in C-band (O-band) as low as 0.1 dB/cm and 0.7 dB/cm (0.14 dB/cm and 1.1 dB/cm) in monomode rib and strip waveguides, respectively, thanks to a H 2 smoothing annealing. In addition to the significant loss reduction, we show that the performance characteristic of the main passive and active components of the photonics platform are preserved or even improved by the smoothing process.
We present a new method to accurately simulate arbitrarily shaped coupled waveguides and ring resonators 100 to 1000 times faster than existing techniques. The new method uses a novel analytic formulation and multivar...
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We present a new method to accurately simulate arbitrarily shaped coupled waveguides and ring resonators 100 to 1000 times faster than existing techniques. The new method uses a novel analytic formulation and multivariate polynomial regression to map the physical dimensions of the simulated waveguides to the complex cross-coupling coefficients of input and output ports, giving the full scattering parameters. We benchmark the results against full-wave solutions and illustrate its use with several application examples.
We present a low-confinement Si waveguide for 4.26 mu m wavelength and apply it to sense CO2 concentrations down to 0.1 %. We demonstrate the highest reported waveguide sensitivity to CO2. 44% of the free-space sensit...
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ISBN:
(纸本)9781943580576
We present a low-confinement Si waveguide for 4.26 mu m wavelength and apply it to sense CO2 concentrations down to 0.1 %. We demonstrate the highest reported waveguide sensitivity to CO2. 44% of the free-space sensitivity. (c) 2019 The Author(s)
Lately, there has been a strong incentive for the development of photonics devices which operate farther in the infrared wavelength range. In this communication, we present a study of the photosensitivity to femtoseco...
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ISBN:
(纸本)9781510624597
Lately, there has been a strong incentive for the development of photonics devices which operate farther in the infrared wavelength range. In this communication, we present a study of the photosensitivity to femtosecond pulses of Mid-Infrared transmitting materials, which are promising candidates to be used as substrates for photo-induced devices, namely, Germanium-Sulfide glass (Ge-S), Barium Gallo-Germanate glass (BGG), and sapphire. We report the formation of single mode waveguides operating at a wavelength of 2.85 mu m, in all three materials. In addition, the inscription of a low-loss depressed clad waveguide in sapphire is demonstrated.
An admittance detecting circuit for silicon waveguide was designed based on the capacitor-integration method using TSMC 0.18 mu m CMOS technology. The detecting circuit monitors the current signal flowing out of the s...
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ISBN:
(纸本)9781728107356
An admittance detecting circuit for silicon waveguide was designed based on the capacitor-integration method using TSMC 0.18 mu m CMOS technology. The detecting circuit monitors the current signal flowing out of the silicon waveguide, converts it into a voltage signal by using a front-end integrator, and finally obtains a varying DC voltage signal which is used to reflect the change of the waveguide admittance. The front-end integrator does not affect the random noise. And the simulation results show that the sensitivity of the detecting circuit is 1.7 x 10(7)V/S, the resolution of the waveguide admittance is 0.5pS.
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