Editorial for the Special Issue on Integrated Photonics and Optoelectronics

Integrated photonic and optoelectronic technologies have become powerful tools in the drive to develop devices that are much smaller and more highly integrated, with lower power consumption and higher functionality. The trend in research and development (R&D) towards the miniaturization of optical and optoelectrical devices and systems [1,2,3,4,5], similarly to recent interest in microelectronics [6,7], has led to a continuous research interest in various integrated photonic and optoelectronic structures and devices [8,9,10,11]. Thus, various easy-to-integrate nanomaterials [12,13,14,15,16,17] with excellent optical and electrical properties, as well as high-precision nanofabrication techniques, have been developed in the last two decades, which have witnessed tremendous progress in integrated photonic and optoelectronic devices.

In this Special Issue (SI) on Integrated Photonics and Optoelectronics, we include 15 papers focusing on the latest research advances both in physical theory and device applications. Through the publication of these results, we hope to present the latest research developments in current challenges and future opportunities for the advancement of integrated photonic and optoelectronic devices, in order to promote the application of these devices in our daily life. Specifically, in this SI, we discuss three current topics in the field of light–matter interactions, including the fundamental theory, such as surface plasma, metasurfaces, and the active manipulation of the optical fields. Twelve publications are included that discuss the latest research on integrated photonic and optoelectronic devices, such as organic light-emitting devices, edge-emitting diode lasers, liquid crystal–quantum dot hybrids, a miniature Fourier transform spectrometer, rod fiber picosecond amplifiers, a thin-film integrated optical intraocular pressure sensor, polarization beam splitters (PBSs), hollow-core anti-resonant fibers, and Mach–Zehnder interferometer (MZI)-based matrix computation.

In particular, Liu et al. [18] numerically demonstrated and investigated a compact and high-power THz radiation source based on the excitation of the surface plasmon polaritons (SSP) mode on a roofed metallic grating by an electron beam. Wang et al. [19] increased the light extraction efficiency of organic light-emitting devices using electrochemically corroded patterned substrates. Shen et al. [20] demonstrated a double-strip array-based metasurface that supports the sharp quasi-bound states in the continuum (quasi-BICs) in terahertz regions. Han et al. [21] introduced the progress of edge-emitting diode lasers, based on a coupled-waveguide concept. Xi et al. [22] investigated an all-optical controlled THz modulator based on a Bi₂Te₃/Si heterostructure under 532 nm and 405 nm continuous-wave (CW) laser illumination. Schmelz et al. [23] presented and evaluated a possible fabrication process based on colloidal polystyrene (PS) nanosphere lithography for the fabrication of such anti-resonant (AR) structures on arbitrarily shaped fused silica substrates. Sun et al. [24] studied several of the most traditional hollow-core anti-resonant fiber (HC-ARF) structures, with the aim of achieving low confinement loss, single-mode performance, and a high insensitivity to bending in the 2 µm band. Bezrukov et al. [25] reported on the developing approaches to modulate the optical behavior of the microfluidic devices, which is conducted by infusing smart hybrids of liquid crystal and quantum dots into microchannel confinement. Zhang et al. [26] proposed a miniature Fourier transform spectrometer using a thin-film lithium niobate electro-optical modulator, instead of the conventional modulator made by titanium diffusion in lithium niobate. Liu et al. [27] enhanced the coupling efficiency of the picosecond rod-type fiber amplifier by carefully setting the optimal mode–field matching. Xu et al. [28] designed a thin-film integrated optical intraocular pressure sensor based on the interferometry principle, which could read out the intraocular pressure value from interference patterns and monitor the value changes in real time simultaneously. Kotlyar et al. [29] discussed the superposition of several parallel identical Laguerre–Gaussian beams with single rings. Sun et al. [30] investigated the spin thermal radiation in a twisted bilayer α-MoO3 metasurface. Mei et al. [31] proposed and realized a PBS based on surface plasmonic resonance in a designed photonic crystal fiber (PCF). Hou et al. [32] identified the main hardware error sources of MZI-based matrix computation, summarized the available hardware error correction methods from the perspective of the entire MZI meshes and a single MZI device, and proposed a new architecture that will largely improve the precision of MZI-based matrix computations without increasing the size of the MZI’s mesh.