An all-polymer spring optomechanical microresonator based ultrasonic sensor is presented. The microresonator is an all-polymer structure with a micro-disk and a cylindrical waveguide based microcavity. Experiment results show that its sensitivity is 987.8 times that of the commercial acoustic sensor at 200KHz, and its acoustic frequency response range is within 50KHz-400KHz. It shows the advantages of smart structure, high sensitivity, and wideband response, and it is expected to have wide applications in smart grid, biomedicine and medical ultrasound imaging.

We introduce an on-chip integrated silicon nitride grating waveguide structure, leveraging Bragg scattered dispersion to achieve local phase-matching of dispersive wave and soliton pulse. This advanced grating structure facilitates precise tuning, thereby enabling localized supercontinuum power enhancement across a designated spectral range.

The operation of the device is affected by the increase in temperature caused by the rough electrodes surface of the thinfilm lithium niobate modulator. We have developed simulation models to analyze the relationship between roughness and maximum surface temperature of gold electrodes and to examine the influence of snowball radius and surface area ratio on the maximum surface temperature. The results indicate that both surface area ratio and snowball radius affect maximum surface temperature change, with the influence of surface area ratio being greater than that of snowball radius within the range of 2-6nm and a surface area ratio between 1.6-2.5, respectively.

Microwave photonics is an interdisciplinary research field that combines the fields of optics and radio frequency. The main functions of microwave photonic systems include photon generation, processing, control and distribution of microwave and millimeter wave (mm-wave) signals. Because of its combined advantages of optics and radio frequency, it is used in applications such as broadband wireless access networks, sensor networks, radar, satellite communications, instrumentation, and warfare systems. This article reviews the development and applications of microwave photonics, providing an overview of photon generation of microwave and millimeter-wave signals, photon processing of microwave and millimeter-wave signals, photon-assisted microwave measurements, fiber-optic radio systems, and integrated microwave photonics. Among them, the optical vector analysis (OVA) technology in Microwave spectrum analysis is analyzed from the principles, development status, structural examples and other aspects, and the OVA based on optical double sideband (ODSB) modulation is studied and simulated in detail. And the performance of the ODSB-based OVA is improved by using the measurement range broadening technology based on optical frequency comb, the measurement error elimination technology based on carrier suppression and balanced photoelectric detection, and the linearly frequency modulation (LFM)-based OVA.

We demonstrate waveguide Modified Uni-Traveling-Carrier (MUTC) Photodetectors (PDs) to complete optical-tomicrowave conversion. Ultra-high 3-dB bandwidths of 137GHz and 163GHz, high responsivities of 0.32A/W and 0.24A/W, and low dark currents of 3nA and 5nA have been achieved for 5×12μm² and 5×8μm² devices, respectively. These PDs demonstrate promising performance for photodetection of high-repetition-rate optical pulses, laying the foundation for the photonic chip-based ultra-stable and low-phase noise microwave generation.

In order to address the challenges brought by high bandwidth requirements to optical communication networks and improve the capacity of ultra-wideband wavelength division multiplexing systems, an optical power optimization algorithm based on the marine predator algorithm is used to optimize the launched power to achieve the goal of maximizing channel capacity. At the same time, the maximum capacity strategy, high and flat capacity strategy, and flattest capacity strategy are applied to meet different transmission requirements, achieving a balance between capacity and ripple. The simulation results show that compared with the brute force search method, the marine predator algorithm-based optimization algorithm significantly reduces the optimization time required and achieves advantages in both total capacity and ripple flatness. This method can be used to quickly optimize optical network design before actual deployment.

We propose and demonstrate a 2-channel coarse wavelength-division multiplexing (de)multiplexer with low crosstalk and flat-top passbands. The device utilizes cascaded Mach–Zehnder interferometers (MZIs) based on a planar lightwave circuit (PLC) to achieve flat passbands with wide bandwidth. By adjusting the arm length differences of each asymmetric MZI, the channel spacing is set to 50nm. As the order increases, the 14dB bandgap between channels can be reduced to as narrow as 10nm, with a bandwidth of up to 40nm—an important feature for coarse wavelength-division multiplexing (CWDM). Various splitter structures were compared, and multimode interference (MMI) waveguides and directional couplers were selected to interconnect different stages, minimizing wavelength-dependent losses. By fine-tuning the coupling ratios of the power splitters based on directional couplers, the crosstalk of the MZIs can be theoretically reduced to below -14dB. The device, fabricated on a silica-based platform with a refractive index contrast of 0.75%, features waveguides with a 6× 6μm cross-section, reducing polarization-dependent loss (PDL). Experimental results demonstrate crosstalk of approximately -10dB across a 40-nm wavelength range, with a PDL of less than 0.3dB per channel, making it suitable for optical communication systems that require large flat-top bandwidths, particularly in metropolitan all-optical networks.

The intensity modulation direct detection (IM/DD) system based on silicon photonic devices stands out as a leading contender for the next generation of short-reach optical communication due to its cost-effectiveness, low power consumption, and compact physical footprint. Nonetheless, its direct representation of digital information through amplitude variations renders them acutely susceptible to transmission impairments. To improve the signal quality at the receiver, digital signal processing (DSP) based equalization plays a pivotal role due to its programmability, flexibility and stability. Among different kinds of equalization methods, neural network (NN)-based equalization algorithms have attracted considerable attention, surpassing traditional algorithms such as feed-forward equalization (FFE), decision feedback equalization (DFE) and Volterra series-based nonlinear equalization (VNLE) et al. This increased attention is attributed to their robust capability for modeling both linear and nonlinear systems. In this paper, by employing a novel NN-based equalization with eight saturation regions activation function, we successfully transmit a 60 GBaud 8-arypulse amplitude modulation (PAM8) signal with the bit error rate (BER) below high-definition forward error correction(HD-FEC) threshold of 3.8×10^-3 and a 70 GBaud PAM8 signal with BER below soft-decision forward error correction(SD-FEC) threshold 2×10^-2 using a 4-layer network architecture. Compared to the traditional activation function such as sigmoid and tanh, 1~3 orders of magnitude of BER can be decreased. The results show that the proposed innovative NN-based equalization has the potential to significantly enhance the performance of the next generation silicon photonics based short-range optical communication systems.

An integrated low-cost and low-loss spot size converter (SSC) for thin film lithium niobate (TFLN) is important to support various high-performance hetero-integrated devices, such as electro-optic modulators, optical frequency combs, and optical phased array. The high performance and power consumption restrict the development of hetero-integrated devices consisting of silicon on insulator and lithium niobate, because of a large difference in mode field sizes between TFLN waveguides and standard single mode fibers or semiconductor lasers. Up to now, most low-loss SSCs whose feature sizes range from tens to hundreds of nanometers, are fabricated by high-cost electron beam lithography. Here we theoretically propose an integrated low-cost and low-loss SSC that reduces the end-face coupling losses in integrated system and improve the coupling efficiency, meanwhile especially its feature size of 1 μm can be fabricated by standard lithography. Based on evanescent wave coupling theory, a Si₃N₄ tapered waveguide surrounded by an amorphous silicon thin layer is used to enhance evanescent wave coupling strength, thereby achieving a high coupling efficiency of 88% between the TFLN and semiconductor lasers. The low-cost and low-loss SSC provides a potential method for hetero-integrated TFLN devices.

We propose an optical transformer model based on the MZI cascaded mesh architecture. By constructing the self-attention layer using MZI cascaded mesh, the model achieved 96.12% accuracy on the MNIST dataset, demonstrating the effectiveness and potential of implementing large transformer models using optical architecture.

Requirements for continuous improvement in performance, increasing miniaturization and density of systems are the main driver in the semiconductor industry to improve the structure of chips and develop new packaging principles. Installations that install semiconductor crystals are necessarily equipped with technical vision systems. These systems include two or more industrial video cameras. The cameras are connected to a powerful computer. Computer software recognizes the position of the crystals in the storage system, monitors and corrects the error in the position of the crystal during transfer and flip operations, recognizes the mounting point of the crystal on the substrate and determines the correctness of the operation in order to identify defects.

The article discusses a technical vision system for an automatic installation of semiconductor crystals. The requirements for cameras are justified and calculated based on the required chip positioning accuracy. A description of the applied technical vision algorithms and the final software product is given.

In the field of CMOS image sensors research, the design and application of Low-Voltage Differential Signaling (LVDS) drivers are key to achieving efficient video signal transmission. As the frequency of LVDS signals continues to increase, issues of signal loss and attenuation during long-distance cable transmission have become more prominent, posing greater challenges to the performance stability of LVDS drivers. This paper establishes a model for CMOS image sensor LVDS drivers and transmission lines, detailing the attenuation mechanisms of LVDS transmission lines and their impact on differential signal transmission. The study focuses on methods for matching the design of LVDS drivers with transmission line characteristics, while also analyzing the interaction mechanisms between the operating states of MOS transistors in the circuit and key variables of the RLGC transmission line model. Using 1Gbps LVDS data and a 20cm flexible transmission ribbon cable as an example, the effectiveness of the matching method was validated through simulation experiments. This method provides technical support for the reliable design of high-speed LVDS drivers in image sensors or other chips, and offers useful references for the engineering selection of LVDS high-frequency transmission lines.

Low light detectors refer to photodetectors that perform imaging in lunar and lower illumination environments. The main types of detectors include electrical gain type detectors represented by EMCCD, photoelectric gain type detectors represented by Microchannel Panel (MCP) ICCD, and the latest scientific level CMOS image sensor (sCMOS). Enhanced low light detectors are more suitable for target detection and edge bright spot detection applications. Extremely dim targets can exceed the noise threshold with extremely high gain, so that the target will not be submerged in noise. Scientific grade CMOS image sensors are more suitable for array low light imaging applications, with better imaging quality than enhanced low light detectors. This article calculates the MTF based on the optical and electrical parameters of the low light detector. The comprehensive MTF at the Nyquist frequency of the three low light detectors are 0.48, 0.13, and 0.63, respectively.

The heterodyne signal of a grating interferometer is formed by the interference of two coherent light beams with a frequency difference. The frequency of the heterodyne signal is equal to the frequency difference of the two light beams. When one beam undergoes Doppler frequency shift, the heterodyne signal experiences a corresponding frequency change. By calculating the phase difference between the reference and measurement heterodyne signals of the grating interferometer, the displacement of an object can be determined. The accuracy and real-time performance of solving this phase difference affect the overall performance of the grating interferometer. Multi-degree-of-freedom grating interferometers play a crucial role in high-precision fields such as lithography machines and astronomical telescope mirror alignment. The phase calculation of interference signals is an important component. Current algorithms hard to balance real-time performance and accuracy effectively. Therefore, to enhance both the precision and real-time performance of grating interferometers, this paper proposes using an extended Kalman filter (EKF) method to solve the phase difference. In the EKF model, the state variables are set as the phase, frequency, and amplitude of the sinusoidal signal, and the calculation is performed through prediction and correction steps. Since the Kalman filter algorithm only uses the current sampling point data for model calculation, it has lower latency. The algorithm was deployed on an FPGA to test the signals generated by a signal generator, achieving a measurement accuracy of 0.03° and a resolution of 0.01°. This research contributes to improving the real-time performance and accuracy of grating interferometers.

In this study, we investigate the application of spectral analysis techniques in software development, addressing the limitations of existing platforms. We introduce an integrated spectral analysis platform designed to improve data processing, enhance algorithmic capabilities, and provide better user interaction. The platform is an advanced peak detection algorithm based on multi-scale, which is optimized for spectral data analysis. The system architecture, built using C++/Qt, ensures reliable data acquisition, processing, and visualisation, while providing a more intuitive and user-friendly interface. This work lays the groundwork for future research and broader applications across multiple disciplines.

Due to increasingly large computational resources, modern neural networks are severely constrained due to their processing speed and energy consumption. Optical neural networks (ONNs), which use photonic structures to process signals at the physical level as an alternative to the computation in the electronic domain provided by traditional neural networks, are an attractive approach to implementing ultra-high-speed, low-energy parallel computation. Nevertheless, current training processes for electronic domain neural networks are optimized from gradient-based training methods, such as backpropagation, not compatible with ONNs with gradient-free features. In this work, a stochastic function-based gradient-free training method, i.e., stochastic function direct feedback alignment (SF-DFA) is demonstrated and evaluated. SF-DFA trains a gradient-free system using stochastic matrices and functions to replace the weights and gradients of the nodes in neural networks. Thus, it is feasible to train ONNs without a prior knowledge of the photonic system and its gradients. In addition, implementing such training process on optical hardware is also known to be possible. A series of studies have been carried out for a spectral slicing neural network (SS-NN) architecture trained by SF-DFA. The SS-NN system uses bandpass filters embedded in optical fiber micro rings to enable slicing of the optical signal spectrum. Our results demonstrate that the training of ONN using SF-DFA can converge efficiently, with higher processing speed and lower energy consumption compared to back-propagation.

With the rapid development of Internet of Things (IoT) and artificial intelligence (AI) technologies, the field of information technology is gradually moving towards the era of optical information processing. Photodetectors convert optical signals into electrical signals, and due to their superior optoelectronic properties, perovskite has become a promising candidate for the next generation of high-speed photodetectors. However, achieving high device efficiency requires the manufacture of perovskite thin films with fewer defects and high carrier extraction capability. Here, we propose that by finely controlling the transport layer and perovskite layer, favorable band bending has been achieved, series resistance has been reduced, and carrier separation has been enhanced. Therefore, the integrated 2Br-POOH-TFHV co processing method achieved a dark current of less than 1X10^-9 a and a response speed of less than 30 ns. In summary, this study proposes a new method for manufacturing high-speed photodiodes.

A hybrid Bloch surface polarized waveguide comprising a dielectric nanowire incorporated at the top of a photonic crystal slab with a sandwiched dielectric arc groove is proposed, and the guiding properties of which are theoretically investigated at the telecommunication wavelength. The introduction of the arc groove offers additional freedom for tuning the supported hybrid mode. By properly choosing the geometrical parameters of the structure, the modified hybrid waveguide could feature significantly enhanced field confinement ability combined with long-range propagation length. The proposed waveguide is shown to be able to enable obviously improved optical guiding performance over the conventional hybrid Bloch surface waveguide due to the tight hybridization of the dielectric mode and the Bloch surface mode in the groove gap. The structure being studied is expected to open up a new route for high-performance photonic integrated devices.

Metasurface has the characteristics of small volume and high integration, which can realize the simultaneous regulation of various degrees of freedom such as phase, polarization and amplitude. The dimensional characteristics of its subwavelength structure have become a hot spot in the optical field. Therefore, the combination of the metasurface and the traditional optical system imaging and polarization imaging can obtain the intensity and polarization information of the target, but also ensure the miniaturization and high performance of the new imaging optical system.

Optical upconverters that convert near-infrared (NIR) light into visible light by directly connecting organic photovoltaic (OPV) devices and organic light-emitting diodes (OLEDs) in series are attracting attention for their potential applications in medicine, night vision, security, and detection. The use of organic system materials eliminates the need for NIR Si integrated circuits and removes limitations on substrate types. The high performance of organic compounds, combined with the manufacturing flexibility of OLEDs, simplifies the production process and reduces costs. The color of the upconversion electroluminescence spectrum can vary across the visible region, from blue to red. Our device achieved a maximum luminance greater than 100cd/m² of green light at 8.5V when illuminated by an 840nm NIR light (1 mW/cm²), and the device reaches an infrared-to-visible upconversion efficiency of 7.23%.

The advancements in integrated thin-film lithium niobate on insulator (LNOI) platform have significantly enhanced the performance of various integrated electro-optic devices, including modulators, external cavity diode lasers, and optical frequency comb generators. Additionally, the development of LNOI has facilitated applications at shorter wavelengths, due to its wide transparency window. The coupling efficiency between laser diodes (LDs) and LN chips is commonly enhanced by designing spot size converters (SSCs). However, achieving high-efficiency SSCs is more challenging at shorter wavelength due to the smaller mode area and the increased confinement of the optical field in LN waveguides. In this study, we present a spot size converter based on hybrid SiN-LN structure, for low-loss light coupling between a III– V gain chip and a LNOI waveguide at 780nm. The parameters of SiN waveguide, LN taper and SiO₂ spacing layer has been optimized in order to enhance the matching of effective refractive indices. The entire SSC structure can be fabricated with two steps of photolithography and etching, demonstrating high fabrication tolerance. Simulations indicate that the coupling losses between the output mode of the LD and the fundamental mode of the LN waveguide are 0.41dB/facet for TE mode and 0.55dB/facet for TM mode at a wavelength of 780nm. Our design is intended to offer efficient light coupling from LD to LNOI chips at short wavelength range, characterized by its simple process and high fabrication tolerance.

A packaging scheme for optical transmission modules based on PAM4 with a data transmission rate of up to 200Gbit/s is proposed to meet the design requirements of 200Gbit/s PAM4 optical transceiver modules. Package integrates four PAM4 electrical/optical conversion ways internally, with a single channel data transmission rate of 50Gbit/s. This article introduces the composition and technical difficulties of the 200Gbit/s PAM4 optical emission module, and then models, simulates, and optimizes the 50Gbit/s data transmission channel. Finally, the sample testing is completed. The test results show that the single channel PAM4 data rate of the sample can reach 50Gbit/s, and the overall PAM4 data rate can reach 200Gbit/s, meeting the design requirements of the optical transceiver module.

Flexible polymer optical waveguides demonstrate outstanding advantages over those on rigid substrates, including flexibility, bendability, lightweight, versatility, and ease of integration. However, flexible polymer optical waveguides face significant challenges in achieving efficient connection and integration with optical fibers. In this study, we propose a simple and reliable method for fabricating flexible polymer optical waveguides on polyimide (PI) using an ultraviolet (UV) lithography process. Additionally, MT connectors are fabricated at each end of the flexible waveguide with passive alignment features. This integration facilitates pluggable and efficient connections between waveguides and MT fiber arrays, significantly improving the ease of assembly and the reliability of optical connections. This integrated connector not only enhances the flexibility and reliability of applications in the field of optical interconnects but also lays the foundation for the development of future high-performance optoelectronic systems.

We proposed the simultaneous wavelength extensions of single-cavity dual-wavelength pulses by using a single erbium-doped fiber amplifier and one section of high nonlinear fiber. By additionally introducing a polarization dependent isolator, polarization dependent loss based gain profile tuning is adopted to obtain dual-wavelength pulses centered at 1533.7 and 1554.8nm. When both dual-wavelength pulses are simultaneously launched into the same erbium-doped fiber amplifier with the bidirectional pump power, the spectral range of the output pulses could be expanded to be from 1500 to 1600nm. Subsequently, the amplified dual-wavelength pulses further pass through a section of high nonlinear fiber, extending the spectrum from 1.2μm to more than 1.75μm. Dual-wavelength pulses are amplified simultaneously by using only one amplifier, showing the feasibility of the simplification of single-cavity dual-comb pulse amplification. These results show the high potential in the applications such as multi-color laser generation and spectroscopy.

In order to solve a series of application problems caused by the difficulty of adjusting prism collimation and the short working distance of small period gratings in current collimation solutions, this paper proposes a six-degree-of-freedom measurement scheme that uses a combination of large period gratings and long focus plano-convex lenses. This solution can achieve six degrees of freedom measurement at a working distance of more than 80mm. The main principle is that the displacement is calculated using the phase information formed by the interference of the four diffracted lights of the two-dimensional grating. The angle is based on the principle of autocollimation. According to the propagation direction of the diffracted light caused by the change of the grating diffracted light with the grating angle changes, thereby changing the angle obtained based on the location changes in the detected diffraction spot, ultimately forming a measurement of six degrees of freedom.

Wire grid polarizers (WGPs) are pivotal in the realm of polarization technology, offering superior performance in various applications. Traditional fabrication techniques, such as electron beam lithography, are often labor-intensive and expensive. Laser interference lithography (LIL) emerges as an efficient and cost-effective alternative for mass-producing high-quality gratings. The process encompasses two critical stages: pattern generation and pattern transfer.

This study presents the design and experimental validation of the method for fabricating polarization gratings. Employing a helium-cadmium laser operating at 442 nm as the illumination source, coupled with a Lloyd mirror interference setup, we achieved an 800 nm period photoresist pattern. Subsequently, inductively coupled plasma etching, utilizing SF6 and O2 gases, transferred the pattern onto a silicon substrate. Double-layer aluminum gratings with an impressive maximum extinction ratio of 30 dB were created through electron beam evaporation. The methodology demonstrated exceptional reliability and stability during experimental evaluations, underscoring their potential for the future of WGP fabrication.

When using a combination of contact lithography and laser interferometric lithography for multi-exposure in separate areas, alignment errors between the mask and the substrate can lead to splicing errors in the photoresist pattern. This can seriously affect the quality of photoresist patterns.

In this paper, we propose a substrate profile-based alignment method to mitigate the effect of the alignment error between the mask and the substrate by calibrating the relative displacement between the mask plate and the substrate. We design a brightfield mask that includes one central processing area and four scale mark areas. The scale mark areas consist of alternating normal and serrated lines, with the line spacing determined by the cell spacing of the processing pattern. Before each exposure, the substrate contour is aligned with the mark lines. Before the next exposure, fine alignment is achieved by observing through a microscope and driving a displacement stage to align the substrate contour with different types of mark lines. With this method, both the offset error and displacement error are reduced to less than 1μm, the photoresist pattern is of good quality, and there is no overlap in the exposure area. This method has wide applicability in multiple exposure processes combining contact lithography and laser interference lithography.

In this manuscript, a novel scheme for generating a frequency-octupled triangular waveform based on an external modulator and fiber grating is proposed. The octuple frequency modulation is realized by dual-parallel Mach-Zehnder modulator (DP-MZM), and two main optical sidebands (±4th) are generated in the optical domain. Then, an intensity modulator (IM) is used to conduct the optical double sideband (ODSB) modulation, after which an optical signal with four sidebands (±4th and ±12th) is obtained. The four spectral lines are separated inside and outside by an optical circulator and fiber grating. After polarization controlling, the power ratio of ±4 and ±12 sidebands can be tuned to 9.5dB, and the expression of optical intensity is approximately equal to the Fourier expansion of the ideal triangular waveform. By applying a 5GHz driving frequency, a triangular waveform with a repetition rate of 40GHz is acquired, which achieves up conversion of octuple frequency.

Phased array radar has important applications in military and civil fields. In order to improve the performance of radar systems, there is a growing demand for increased the signal bandwidth. However, with the larger bandwidth, the traditional phased array system based on microwave phase shifter will have obvious beam squint phenomenon when realizing beam pointing adjustment. Hence, the microwave photonic broadband phased array with the core of light-controlled microwave technology has become a much-appreciated realization of broadband phased array. For the beam squint phenomenon caused by broadband signals, this paper proposes a scheme of using the true time delay introduced by a continuously tunable Mach-Zehnder interferometer for compensation in optical domain. Four different bandwidth with different center frequencies were designed and validated to achieve a squint free beamforming within the scanning angles of ±30°.