In this paper, the annular folded lens (AFL) is applied to the realization of a miniaturized system for the visible and near-IR spectrums (0.45-1.1 mu m). In order to correct the chromatic aberration, a hybrid AFL is designed with the multilayer diffractive optical element (MLDOE) in which the substrate materials are precision molded glasses. We propose a new design method of the MLDOE to improve the polychromatic integral diffraction efficiency (PIDE) that makes it suitable for the optical path of the AFL. By comparing the characteristic angle weighted PIDE (CAW-PIDE), the optimal microstructure heights of the MLDOE can be obtained, and the effect of diffraction efficiency on image quality can be minimized for the entire incident angle range. The design results show that the ratio of total length to the focal length is only 0.332, and comprehensive modulation transfer function considering the diffraction efficiency is larger than 0.26 at 166 lp/mm. This study can provide a new idea for designing a broadband, miniaturized, and low-cost imaging system. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Free-space optical communication (FSOC) enables high-speed, secure, and scalable data transmission, with great potential for space–ground networks. However, existing FSOC systems predominantly employ point-to-point transmitters, each requiring bulky beam steering devices with complex control mechanisms, which severely limits their feasibility for multi-node micro-platform applications. Here, to address such a challenge, we propose a novel point-to-multipoint FSOC scheme based on reconfigurable SiC gratings, which are directly fabricated in stretchable PDMS films via femtosecond laser-induced carbide precipitation. The reconfigurable SiC transmission gratings are with good transparency (~91.9% at 1550 nm), dynamic beam steering capability (hundred-milliradian level), and an ultralightweight design (single grating: 0.4 g). The SiC fringes are specially fabricated within the internally symmetric region of the PDMS film to mitigate the structure distortion during stress regulation, significantly enhancing the long-range transmission capability in degraded atmospheric channels. The system supports 1-to-7 and 1-to-9 dynamic optical communication for 1D and 2D configurations, respectively. In a state-of-the-art 225-meter outdoor experiment, the system achieves reliable 10 Gbps transmission for each node. This portable FSOC system overcomes the limitations of conventional systems, enabling scalable and flexible multibeam steering. This approach establishes a robust foundation for long-range, multinode, and high-capacity FSOC networks among spatial micro-platforms such as unmanned aerial vehicles and micro-satellites.

Driven by the rapid innovation of science and technology and industrial manufacturing technology, virtual reality display technology has developed rapidly. At present, the application of virtual reality display technology is expanding in many fields such as military, medical, aviation and education. This paper analyzes the imaging principle of the human vision system and the optical performance requirements of VR heads-up display, summarizes the current design scheme of VR heads-up optical imaging system, focuses on the principle and index parameters of each optical system, and compares the advantages and disadvantages of different schemes. The development prospects and directions of virtual reality headset displays are also prospected.

With the development of all‐optical networks, all‐optical devices have become a research hotspot in recent years. Two‐dimensional materials, represented by graphene and black phosphorus, have attracted great interest in the scientific community due to their excellent optical, electrical, magnetic, and mechanical properties. Bridging the gap between fiber optics and nanotechnology, microfibers can interact with light and matter at the micro or even nanoscale. By combining two‐dimensional materials with microfibers, composite waveguides can be formed. They have the advantages of high nonlinear effect, all‐fiber structure, and high damage threshold, etc. The composite waveguide can be directly applied to optical fiber communication systems, and plays an important role in the field of all‐optical signal processing with a huge application prospect. In this review, the properties of typical 2D materials are first introduced. Next, the preparation methods of the relevant equipments are introduced and compared. Then, the all‐optical signal processing technology based on 2D material‐integrated microfiber composite waveguide is reviewed. The latest developments of all‐optical modulators, all‐optical wavelength converters, all‐optical logic gates and all‐optical thresholding devices are presented. Finally, the challenges and opportunities for the future development of 2D materials‐integrated microfiber optoelectronic devices are summarized.

Adaptive free-space optical (FSO) communication links have been extensively studied in order to adapt to variable atmospheric channel environments due to factors such as atmospheric turbulence. As a supporting technology, an all-in-one BPSK/QPSK switchable transmission and reception method is proposed and experimentally demonstrated for adaptive modulation format switching in FSO links. The transmission and reception of both modulation formats are realized based on the same IQ modulator and single-photodetector coherent receiver. Simulation and experimental results show that the QPSK signal has a power penalty of about 3–4 dB compared to the BPSK signal with a BER of about 1 × 10⁻³. The basis for format switching is given according to the various atmospheric channel conditions. The proposed method provides a flexible and efficient solution for variable FSO communication environments to improve their performance.