Coupled mode theory for waveguide arrays is extended to next-nearest neighbor interactions using propagation equations. Both lateral diffraction and propagation of Floquet-Bloch waves are altered respectively by extra coupling and non-orthogonality between isolated waveguide modes. The analytical formula describing the distortions of the diffraction relation is validated by direct numerical simulation for weakly coupled InP and GaAs shallow ridge waveguides and for strongly coupled Si-SiO(2) buried strip waveguides. The impact of extended coupled mode theory on propagation and diffraction design in waveguide arrays is discussed with reference to available experimental work.
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http://dx.doi.org/10.1364/OE.18.007157 | DOI Listing |
A wavelength demodulation method for ultra-short fiber Bragg grating (US-FBG) sensors based on an arrayed waveguide grating (AWG) and a convex optimization algorithm is proposed and demonstrated. Instead of measuring the output power ratio of the two adjacent AWG channels as previously done, in this work the wavelength demodulation is realized by reconstructing the US-FBG spectrum. The principle of spectral reconstruction involves using an AWG to sample the spectral information of US-FBG and constructing underdetermined matrix equations with the obtained prior information on transmission responses and the detected output power from multiple AWG channels.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, 75013 Paris, France.
Harnessing high-dimensional entangled states of light presents a frontier for advancing quantum information technologies, from fundamental tests of quantum mechanics to enhanced computation and communication protocols. In this context, the spatial degree of freedom stands out as particularly suited for on-chip integration. But while traditional demonstrations produce and manipulate path-entangled states sequentially with discrete optical elements, continuously coupled nonlinear waveguide systems offer a promising alternative where photons can be generated and interfere along the entire propagation length, unveiling novel capabilities within a reduced footprint.
View Article and Find Full Text PDFAdv Mater
December 2024
State Key Laboratory of Luminescent Materials and Devices, School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China.
The emerging metal halide perovskites are challenging the traditional scintillators in the field of radiation detection and radiography. However, they lack the capability for remote and real-time radiation monitoring and imaging in confined and hostile conditions. To address this issue, details on an inorganic scintillating glass fiber incorporating perovskite quantum dots (QDs) as highly efficient pixelated radiation emitters are reported, while the glass fibers themselves serve at the same time as low-loss waveguides, enabling long-distance and underwater X-ray detection.
View Article and Find Full Text PDFACS Photonics
December 2024
School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China.
Photonic topological insulators with boundary states present a robust solution to mitigate structure imperfections. By alteration of the virtual boundary between trivial and topological insulators, it is possible to bypass such defects. Coupled resonator optical waveguides (CROWs) have demonstrated their utility in realizing photonic topological insulators, as they exhibit distinct topological phases and band structures.
View Article and Find Full Text PDFNanophotonics
November 2024
College of Science, China University of Petroleum (East China), Qingdao 266580, China.
Owing to its topological properties and band collapse, Floquet helical photonic lattices have gained increasing attention as a purely classical setting to realize the optical analogues of a wide variety of quantum phenomena. We demonstrate both theoretically and numerically that light propagation in an appropriately designed helical superlattice can exhibit spatial photonic Zitterbewegung effect, i.e.
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