https://www.selleckchem.com/products/ly333531.html In the inverse design of nanophotonic devices, mathematical optimization methods are generally used to perform local optimization in the design region to obtain the physical structure that meets design expectations. These methods usually produce good structures. However, due to the lack of physical considerations, most of the inverse design methods for nanophotonic devices use random initial topology as the initialization for optimization, which will inevitably cause a waste of computing resources. In this Letter, we propose a method based on a time-reversal technique to quickly determine the induced source of the physical structure in the design region and, thus, obtain the initial topological structure of the nanophotonic devices. For a nanophotonic 90°-bend waveguide and 90°-bend power splitter waveguide, numerical examples show that the initial topology obtained by our method not only has good initial performance, but also can be used as a reasonable initialization for inverse design.We propose and demonstrate a Michelson interferometer modulator with integrated Bragg reflectors on a silicon-rich nitride-thin-film lithium niobate hybrid platform. High-reflectivity Bragg reflectors are placed at the ends of both arms, which double the electro-optic (E-O) interaction length and reduce the velocity mismatch between the microwave and optical wave. The presented Michelson interferometer modulator achieves a measured half-wave voltage length product as low as 1.06 V cm and high-speed modulation up to 70 Gbps. A 3-dB E-O bandwidth beyond 40 GHz is also achieved, which is, to the best of our knowledge, the highest modulation bandwidth of Michelson interferometer modulators.We report the experimental observation of cylindrical-vector vortex solitons (CVVSs) in lead glass with strongly thermal nonlocal nonlinearity. The formations of radially and angularly polarized solitons with topological charge of $l = 1$ were observe