The superior confinement of light provided by the high refractive index contrast in Si/SiO2 waveguides allows the use of sub-micron photonic waveguides. However, when downscaling waveguides to sub-micron dimensions, p...
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ISBN:
(数字)9781510615601
ISBN:
(纸本)9781510615601
The superior confinement of light provided by the high refractive index contrast in Si/SiO2 waveguides allows the use of sub-micron photonic waveguides. However, when downscaling waveguides to sub-micron dimensions, propagation losses become dominated by sidewall roughness scattering. In a previous study, we have shown that hydrogen annealing after waveguide patterning yielded smooth silicon sidewalls. Our optimized silicon patterning process flow allowed us to reduce the sidewall roughness down to 0.25 nm (16) while maintaining rectangular Strip waveguides. As a result, record low optical losses of less than 1 dB/cm were measured at telecom wavelengths for waveguides with dimensions larger than 350 nm. With Rib waveguides, losses are expected to be even lower. However, in this case the Si reflow during the H-2 anneal leads to the formation of a foot at the bottom of the structure and to a rounding of its top. A compromise is thus to be found between low losses and conservation of the rectangular shape of the Rib waveguide. This work proposes to investigate the impact of temperature and duration of the H-2 anneal on the Rib profile, sidewalls roughness and optical performances. The impact of a Si/SiO2 interface is also studied. The introduction of H-2 thermal annealing allows to obtain very low losses of 0.5 dB/cm at 1310 nm wavelength for waveguide dimensions of 300-400 nm, but it comes along an increase of the pattern bottom width of 41%, with a final bottom width of 502 nm.
We discuss the fabrication of 1 mol% Eu-doped 70 SiO2-(30-x) HfO2-x ZnO (x = 0, 2, 5 and 7 mol%) ternary glass-ceramic waveguides, and the effect of ZnO-HfO2 hybrid nanocrystals on the optical gain in Eu-doped ternary...
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ISBN:
(数字)9781510618930
ISBN:
(纸本)9781510618930
We discuss the fabrication of 1 mol% Eu-doped 70 SiO2-(30-x) HfO2-x ZnO (x = 0, 2, 5 and 7 mol%) ternary glass-ceramic waveguides, and the effect of ZnO-HfO2 hybrid nanocrystals on the optical gain in Eu-doped ternary waveguides. Formation and growth of ZnO-HfO2 hybrid nanocrystals have been observed in the TEM images with increase of ZnO concentration in the samples. Waveguiding properties of Eu-doped ternary waveguides were measured using lab-built prism-coupling technique. Propagation losses of the waveguides were measured using photometric detection technique and found to be between (0.3 to 0.6)+/- 0.2 dB/cm. We have further investigated the optical amplification of red emission line (D-5(0) -> F-7(2)) of Eu-ions in these waveguides using the variable stripe length method wherein the waveguides were pumped by continuous wave 532 nm laser in a stripe-like geometry using cylindrical lens The optical gain coefficients are found to be 5.3, 4.8, 3.7 and 0.1 cm(-1) for ZnO concentration of 0, 2, 5 and 7 mol% respectively.
作者：
Garnier, JosselinCMAP
CNRS Ecole polytechnique Institut Polytechnique de Paris Palaiseau Cedex91128 France
An asymptotic analysis of wave propagation in randomly perturbed waveguides is carried out in order to identify the effective Markovian dynamics of the guided mode powers. The main result consists in a quantification ...
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We present the general conditions to realize fourth order exceptional points of degeneracy (EPD) in two uniform (i.e., invariant along z) coupled transmission lines (CTLs). The CTLs are modeled as distributed generic ...
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ISBN:
(纸本)9781538671023
We present the general conditions to realize fourth order exceptional points of degeneracy (EPD) in two uniform (i.e., invariant along z) coupled transmission lines (CTLs). The CTLs are modeled as distributed generic components where each line (when uncoupled) may support forward propagation, backward propagation or evanescent modes. We show the novel and important fact that a fourth order EPD may be supported in uniform CTLs when there is coupling between a forward propagating mode and an evancent mode. We also provide a microstrip possible implementation of a uniform CTL exhibiting fourth order EPD using a very subwavelength unit cell length.
We consider the Dirichlet and Neumann problems for the Laplace operator in periodic waveguides. Integro-differential connections between the solution and its normal derivative, interpreted as a finite-dimensional vers...
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This paper addresses a wave-based non-destructive testing technique for the detection of defects in assemblies of waveguides connected to curved joints. To achieve this goal, the wave finite element (WFE) method is us...
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ISBN:
(纸本)9789073802995
This paper addresses a wave-based non-destructive testing technique for the detection of defects in assemblies of waveguides connected to curved joints. To achieve this goal, the wave finite element (WFE) method is used. It provides an efficient numerical means to compute waves in periodic structures (waveguides), and compute the reflection and transmission coefficients of these waves around defects and curved joints. The so-called scattering matrices of the defects and the joints can be formulated from a finite element modeling. The measured reflection coefficients due to defects are tightly connected to the characteristics of the curved joints. As it turns out, their characteristics can be tuned in an appropriate way to improve the magnitude of the reflected signals. An optimization procedure for the design of curved joints, using the WFE framework, is therefore proposed. Numerical experiments are carried out by considering two 2D waveguides - i.e., one healthy/perfect waveguide and a second one containing a defect - connected to a curved joint which is parametrized with respect to its curvature radius and its curvature angle.
Since the pioneering work of Kawata and Tani, photonic waveguides have long been regarded as efficient optical conveyor belts for potential lab-on-a-chip applications. Indeed, near-field optical forces arising at the ...
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ISBN:
(纸本)9781728104690
Since the pioneering work of Kawata and Tani, photonic waveguides have long been regarded as efficient optical conveyor belts for potential lab-on-a-chip applications. Indeed, near-field optical forces arising at the surface of such waveguides lead to efficient on-chip guided propulsion of micro- and even nanoparticles, as well as cells and bacteria in liquid solutions. However, achieving stable and precisely controlled optical trapping of particles at the surface of a waveguide has been made possible only recently, and even then, it still requires complex photonic electro-optic tools to produce and handle on-chip standing waves.
We report the fabrication of ultra-compact flexible optical waveguides in polydimethylsiloxane through multiphoton direct laser writing, for the first time without a photoinitiator. A transmission loss of 0.03 dB/cm w...
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ISBN:
(纸本)9781509063741
We report the fabrication of ultra-compact flexible optical waveguides in polydimethylsiloxane through multiphoton direct laser writing, for the first time without a photoinitiator. A transmission loss of 0.03 dB/cm was measured in the 650-700 nm band.
We prove a Limiting Absorption Principle for Schrödinger operators in tubes about infinite curves embedded in the Euclidian space with different types of boundary conditions. The argument is based on the Mourre t...
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We show that subwavelength silicon-rich nitride waveguides efficiently sustain high-speed transmissions at 2 µm. We report the transmission of a 10 Gbit/s signal over 3.5 cm with negligible power penalty. Paramet...
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