Inverse design for material anisotropy and its application for a compact X-cut TFLN on-chip wavelength demultiplexer

Inverse design focuses on identifying photonic structures to optimize the performance of photonic devices. Conventional scalar-based inverse design approaches are insufficient to design photonic devices of anisotropic materials such as lithium niobate (LN). To the best of our knowledge, this work proposes for the first time the inverse design method for anisotropic materials to optimize the structure of anisotropic-material based photonics devices. Specifically, the orientation dependent properties of anisotropic materials are included in the adjoint method, which provides a more precise prediction of light propagation within such materials. The proposed method is used to design ultra-compact wavelength division demultiplexers in the X-cut thin-film lithium niobate (TFLN) platform. By benchmarking the device performances of our method with those of classical scalar-based inverse design, we demonstrate that this method properly addresses the critical issue of material anisotropy in the X-cut TFLN platform. This proposed method fills the gap of inverse design of anisotropic materials based photonic devices, which finds prominent applications in TFLN platforms and other anisotropic-material based photonic integration platforms

Dimensionality Reduced Antenna Array for Beamforming/steering

Beamforming makes possible a focused communication method. It is extensively employed in many disciplines involving electromagnetic waves, including arrayed ultrasonic, optical, and high-speed wireless communication. Conventional beam steering often requires the addition of separate active amplitude phase control units after each radiating element. The high power consumption and complexity of large-scale phased arrays can be overcome by reducing the number of active controllers, pushing beamforming into satellite communications and deep space exploration. Here, we suggest a brand-new design for a phased array antenna with a dimension reduced cascaded angle offset (DRCAO-PAA). Furthermore, the suggested DRCAO-PAA was compressed by using the concept of singular value deposition. To pave the way for practical application the particle swarm optimization algorithm and deep neural network Transformer were adopted. Based on this theoretical framework, an experimental board was built to verify the theory. Finally, the 16/8/4 -array beam steering was demonstrated by using 4/3/2 active controllers, respectively

Fast-reconfigurable frequency comb generation based on AlGaAsOI waveguide with electro-optic time lens

Abstract Tunable optical frequency combs offer a flexible solution for specific applications such as dual-comb spectroscopy, optical communications and microwave photonics, delivering improved precision, compatibility, and performance. However, previously, there has been a trade-off between reconfigurability and system simplicity in comb generation. Here, we present a fast-switched repetition rate frequency comb system that utilizes an electro-optic modulation time-lens technique with a high third-order nonlinear AlGaAsOI waveguide. Only one stage of modulator is used in the time-lens system which significantly reduces the complexity of the overall system. Our system allows for tuning of the center wavelength from 1542 nm to 1556 nm, as well as independent adjustment of the repetition rates from 18 GHz to 26.5 GHz, enabling fast-switching capabilities. Additionally, our system exhibits a high pump-to-comb conversion efficiency of up to 67.9%. It also demonstrates robustness to temperature changes and environmental instability. All the involved devices can be integrated onto a single chip, making this comb suitable for various applications