This PDF file contains the front matter associated with SPIE Proceedings Volume 12556, including the Title Page, Copyright information, Table of Contents, and Conference Committee listings.

Two-dimensional (2-D) nanomechanical resonators are interesting for the tunability of their resonant frequencies over wide frequency ranges using electrical means. These resonators are often made by transferring thin membranes of layered materials onto cavities fabricated in oxidized silicon wafers. The resonant frequency of vibrational modes is tuned by applying a dc voltage between the membrane and the silicon substrate acting as a global gate, which creates an electrostatic force that pulls the membrane towards the global gate and changes the strain within the membrane. Here, we measure the frequency response of 2-D resonators based on few-layer graphene transferred onto cavities milled in silicon oxide using focused ion beam (FIB) lithography. In response to a step in gate voltage, we find that resonant frequencies of vibrational modes decay in time. To explain this phenomenon, we propose that residual gallium ions from the ion beam form a floating gate at the bottom of the cavity and create a weak link between this floating gate and the graphene membrane. Leakage of charges between graphene and the floating gate lowers the strain induced by the voltage applied between graphene and the gate electrode, making the resonant frequency of the graphene membrane decay. We present a model based on a floating gate structure to effectively explain the decay of graphene resonant frequency in our device.

Two-dimensional (2-D) nanomechanical resonators are based on thin layers of graphene, black phosphorus, transition metal dichalcogenides and van der Waals heterostructures. Detection of nanomechanical vibrations can be done using optical reflectometry, whereby vibrations modulate the optical reflectance of the resonator. For this type of detection to work, it is essential to fabricate cavities with a precise depth. Here we report on the fabrication of 2-D nanomechanical resonators in which the cavity is made using focused ion beam (FIB) lithography. We mill down an array of cylindrical cavities with the same diameter but different depths. We drive vibrations electrically and detect vibrations optically. At the resonant frequency of vibrations, we observe that the measured signal, which is proportional to the vibrational amplitude and to a transduction factor, is different for different cavity depths. Since all resonators have the same diameter, are made of the same graphene flake and are actuated the same way, our observation implies that the transduction factor changes with cavity depth. Using principles of thin film optics, we show that each estimated transduction factor is indeed consistent with the dimensions of the resonator, including the cavity depth, the thickness of the patterned substrate, and the number of graphene layers. This result supports the idea of using FIB to fabricate cavities for 2-D nanomechanical resonators, instead of using standard wet etching or reactive ion etching which require additional lithography steps and cannot easily be used to pattern cavities with different depths on the same substrate.

In this paper, a transmissive tunable metasurface based on phase-change alloy Ge₂Sb₂Te₅ (GST) has been proposed, exhibiting the function of switching between a quarter wave plate (QWP) and a half wave plate (HWP) in mid-IR region, i.e., providing circular-to-linear and circular-to-circular polarization conversions at amorphous state and crystalline state, respectively. For the amorphous GST, linear polarized (LP) transmitted beams with angles of linear polarization (AoLPs) close to ±45° can be obtained with the degrees of linear polarization (DoLPs) close to 1 under normal circular polarized (CP) excitations at the wavelength varying from 4.8 to 5.2 μm. As for the crystalline GST, the normally incident CP lights can be converted into the corresponding orthogonal CP beams with the degrees of circular polarization (DoCPs) close to ±1 within the wavelength range from 4.95 to 5.05 μm. The polarization state diagrams of the transmitted beams with good profiles further prove the good performance of the designed GST metasurface. Our finding paves the way for the development of flat polarization optical components with switchable functionalities.

We designed and demonstrated a silicon-on-insulator (SOI)-based multifunctional 1×4 multimode interference (MMI)waveguide that can be employed as a 1310/1550 nm wavelength demultiplexer and a 3-dB power splitter at the sametime. The direct binary search (DBS) algorithm is applied to inversely design and optimize the multifunctional MMI. Simulation results show that the insertion loss of our device is 0.67 and 0.50 dB for the 1310 and 1550-nmchannels, while the wavelength isolation values are up to 24 and 37 dB, respectively. The 3-dB bandwidth of our device is largerthan 350 nm, covering the whole O-band, C-band and L-band. Our MMI waveguide has an ultra-compact footprint of 5×2.5 μm², which is more than one order of magnitude smaller than the conventional MMI-based demultiplexers orpower splitters.

In this paper, we demonstrate a reconfigurable device that could realize modulation on TE₀ polarization or TM₀ polarization selectively. The device consists of a pair of TM₀-TE₁/TE₁-TM₀ mode converters, two TE₀-TE₁ mode exchangers, and a TE₁ mode micro-ring modulator. 32 Gb/s on-off keying modulation is successfully demonstrated both for TE₀ polarization and TM₀ polarization.

Single photon avalanche diodes based on the state-of-the-art CMOS fabrication nodes have inspired a new era of low cost and high integration quantum-level image sensors. They have a broad application prospect in biology, chemistry, medicine, and many other fields of science and engineering. For each application, the diodes’ structure and size must be optimized empirically, while the device performance is difficult to predict theoretically. To assist in this iterative design process, this paper simulates the single photon avalanche diodes’ structures by Sentaurus-TCAD to optimize the electrical and optical performance. A new modeling method of PDP is proposed. The designed and manufactured SPADs have good performance.

Thin-film lithium-niobate-on-insulator (LNOI) is a promising platform for nonlinear optics and optical interconnect. It is critical to realize high efficiency for coupling optical signal into lithium niobate photonic integrated circuits. Here we demonstrate a low-loss edge coupler for coupling between a standard optical fiber and sub-micrometer LN strip waveguides. The coupler consists of an inverse tapered mode size converter, as well as a tapered SU-8 polymer curved waveguide which functions an interface between the single-mode optical fiber and the mode size converter. The simulation shows that coupling efficiencies for TE mode and TM mode are -0.42 dB and -0.75 dB at 1550nm, respectively. The coupling efficiency is higher than -0.77 dB for both TE and TM mode in wavelength range of 1450 nm to 1650 nm. This means that our edge coupler has polarization insensitivity and ultra-wide bandwidth.

We demonstrate a hybrid solid-state beam scanner based on 32-channel silicon nitride optical switch with the assistance of transmission blazed grating. The optical switch exhibits rather low power consumption of 7.2 mW/π. Besides, end-fire antennas offer high optical efficiency with less reflection. Non-mechanical two-dimensional beam steering with range of 14.32° × 9.94° and beam divergence of <0.1° is achieved by wavelength tuning and onchip optical path switching. The proposed system eliminates complex control and time-consuming array phase calibration, providing a flexible, scalable and effective solution for all solid-state coaxial light detection and ranging (LiDAR) technology.

In this paper, surface grating Vertical Cavity Surface Emitting Laser(VCSEL) are fabricated by displacement Talbot lithography (DTL) exposure technology, and the effects of process parameters and anti-reflection layers on the quality of fabricated surface grating VCSEL are systematically studied. The experimental results show that this process can fabricate surface grating VCSEL with a depth of 20-150 nm. When the exposure dose is 30 mJ·cm^-2, the exposure light intensity is 2 mW·cm^-2, and the developing time is 1 min, the results that meet the experimental requirements are obtained. The experimental results show that the method of surface grating VCSEL fabricated by DTL exposure technology can replace EBL exposure technology. It is of great significance to improve the performance of VCSEL.

A polarization-insensitive optical filter based on silicon and silicon nitride film is demonstrated. The lateral-shift apodization is introduced to suppress the sidelobes. The fabricated optical filter shows polarization-insensitive performances with large 3dB-bandwidths of 3.5–5.1 nm, low losses of 1.72-1 dB, decent SLSRs of 18.5-19.1 dB for both polarizations.

As a key link in the practical application of optical modules, the packaging technology of optoelectronic devices plays a crucial role in the performance of products. Among them, the optical coupling technology is an important link in the packaging design process, and the lensed fiber coupling method still occupies a large proportion in the packaging technology due to its simple structure and low cost. In this paper, by adjusting the parameters of the taper angle and curvature radius of the lensed fiber, a simulation model of the optical coupling between the lensed fiber and commercial lasers is established, and the optical coupling efficiency and optical tolerance of the lensed fiber under different horizontal coupling distances and angular offsets are analyzed in detail. In addition, the coupling performance of the lensed fiber with two different manufacturing processes, the ground- cone lensed fiber (GCLF) and the fused-cone lensed fiber (FCLF), was compared and analyzed. According to the comparative analysis results, under the optimal parameters, the maximum coupling efficiency of GCLF reaches 89.35%, and the maximum coupling efficiency of FCLF reaches 85.59%. By adjusting the alignment angle of the laser light source in the horizontal and vertical directions, the 3db alignment tolerances of GCLF in two directions are 2.17μm and 2.05μm, respectively, and the 3db alignment tolerances of FCLF in two directions are 2.08μm and 1.96μm, respectively. From this, it can be seen that GCLF has higher coupling performance than FCLF, and a higher alignment tolerance during the package alignment process.

We propose and demonstrate a liquid crystal (LC) embedded dielectric metalens with continuously tunable focal length operating at 35 GHz. The lens is composed of a dielectric square hole array filled with a homogenously pre-aligned LC layer. The orientation of LCs can be electrically or magnetically varied, resulting in the dynamic tuning of the transmitted phase of the meta-unit. By elaborately designing the dimension of each meta-unit, the metalens can focus the wave with a variable focal length. We numerically demonstrate a metalens with its focal length tuning from 196.1 to 166.5 mm when the LC orientation gradually varies from 0° to 90°. The transmission of each meta-unit and the full width at half maximum of the focusing intensity are also analyzed, indicating an efficient and satisfactory focusing property. Such a compact and tunable metadevice may facilitate the microwave imaging, communication and so on.

We address inverse design of plasmonic Fano-resonant metasurfaces by using a tandem neural network (TNN) which can correctly predict both materials and structural parameters of target spectra. To train this TNN, 19530 groups of data from asymmetric double bar (ADB) nanostructures of varied dimensional parameters and different materials (Ag, Cu, and Al) respectively were collected. Our approach successfully addresses a non-uniqueness problem that commonly exists in nanophotonic inverse design. Besides, we choose target spectra generated outside the collected dataset in order to test the applicability and robustness of the TNN, which proves that the developed TNN is able to retrieve the nanoparticles of appropriate sizes and compositing material matching well Fano-profiled unknown target spectra within the spectral window of study.

Multimode waveguide Bragg gratings filters with square shape amplitude responses and well-controlled dispersion characteristics are achieved by the Time-Domain Layer Peeling method for the first time, the Bragg grating structures can be mapped by the complementary lateral-misalignment modulation apodization. Three filters with different amplitude and phase responses are demonstrated. For the dispersion-less filter, the dispersion compensation filter and the three-channel dispersionless filter, the 3 dB bandwidth and the group delay of the realizable spectral responses are 4.0 nm, 4.7 nm, 2.1 nm and 0 ps/nm, 5.7 ps/nm, 0 ps/nm, the group delay ripples have a standard deviation of 1.7 ps, 1.5 ps, and 2.0 ps. The multimode relaxes the fabrication requirement in terms of both the lithography resolution and minimum feature size/spacing while maintaining the advantages of low insertion loss.

In this paper, highly efficient TE₀-TE₁ and TM₀-TE₁ conversions are achieved on SOI chips by optimizing the edge of mode converters employing the adjoint shape optimization method. At the central wavelength of 1550 nm, the conversion efficiencies of the device reaches 99.6% for TE₀-TE₁ conversion and 96.0% for TM₀-TE₁ conversion, while the loss are only 0.016 dB and 0.17 dB, respectively. Besides, the extinction ratio reaches 31.2 dB and 29.5 dB. The bandwidth characteristics of the devices are also numerically investigated. As the wavelength varies from 1500 nm to 1600 nm, the conversion efficiency for TE₀-TE₁ conversion can be kept above 96.6% and the extinction ratio is kept above 15.7 dB, while the insertion loss is kept below 0.14 dB. As for TM₀-TE₁ conversion, the conversion efficiency is above 92.6%, the extinction ratio is over 15.6 dB and insertion loss is below 0.33 dB within the wavelength range from 1505 nm to 1585 nm. Considering the influence of fabrication process on the performance of devices, the fabrication tolerance of mode converters is investigated by adjusting the width of devices. For both converters, the conversion efficiencies can be kept above 91.9%, while the insertion loss is less than 0.34 dB as the width variation of ± 20 nm at 1550 nm. The proposed mode converters take advantages of large bandwidth, high conversion efficiencies, low insertion loss and high fabrication tolerance, paving the path to realize efficient on-chip mode conversion in a cost-effective way.

Based on the asymmetric directional coupler, a polarization beam splitter based on silicon on Insulator (SOI) platform is designed for the wavelength range of 1500nm-1600nm in optical communication in this letter. The asymmetric directional coupler is composed of a regular strip shape waveguide and a sub-wavelength grating waveguide. The influence of the grating period, grating depth, and duty cycle on its polarization characteristics is analyzed. The simulation results show that the polarization extinction ratio (PER) of TE polarization is 20-23 dB and the insertion loss (IL) is 0.01-0.04dB, in the wavelength range of 1500–1600nm, while the PER of TM polarization is 15-26 dB and the IL is 0.3-0.6dB. Especially, the PER and IL are 21 dB (26 dB) and 0.31 dB (0.26 dB) for TE (TM) at the wavelength of 1550 nm. Moreover, the minimum feature size of this device is 25 μm2 . It can be effectively used in semiconductor photoelectronic devices.

A kind of waveguide geometry extraction method based on optical measurements was proposed. By designing two Mach-Zehnder interferometers (MZIs) with different arm lengths, the width and height of the physical geometry of fabricated waveguides could be accurately extracted with the help of MZIs’ optical measured spectrum results. The extracted results on the CUMEC multi-project wafer service (MPW) showed that the mean width and height of the fabricated waveguide were 463.46 nm and 213.58 nm, respectively, while their standard deviation values were 3.82nmand 2.13 nm, respectively.

We demonstrate 32-channel dispersive optical phased arrays on a Si₃N₄-on-SOI integration platform. The phase difference is introduced by the arrayed waveguide. Beam steering in phased-array direction with an aliasing-free range of 22.4° and free spectrum ranges of ∼ 60 nm and ∼ 6 nm is achieved. Meanwhile, the main lobe is deflected simultaneously by 19.67° in the other direction by tuning the wavelength from 1500 nm to 1630 nm. Measurement results show that the dispersive optical phased array provides a compact, low-power and massively parallel solution for LiDAR applications.

With the development of LED technology and the innovation of shooting concept, the virtualized production technology based on LED curtain wall has attracted much attention in film and television creation. This technology uses the virtual imaging of the LED curtain wall as the shooting background to achieve real-time rendering and production. At the same time, the LED curtain wall, which is composed of multiple pixels, also has the lighting function. This paper summarizes the current lighting technology in virtual filming based on LED curtain wall and proposes solutions for the LED curtain wall’s visible distance and Moire pattern during filming.

High efficient photodetectors are of paramount importance in optical communications as the advent of the big data era. The bandwidth-efficiency trade-off of detectors has always been being a limiting problem. We demonstrate here that ultrahigh absorption more than 85% can be achieved at wavelength 1300 nm by only patterning an ultrathin germanium (Ge) slab with a periodic array of air holes, which is about 3 times comparing with that of a uniform Ge slab of the same thickness. The enhanced absorption is mainly attributed to the critical coupling of the guided resonance of the photonic crystal slab. This work paves a way for high-responsivity surface-illuminated photodetection with a patterned ultrathin Ge slab.

Filter of linear beam smoke detector is the supporting equipment for linear beam smoke detector. The study of its filtering characteristic and calibration method is developed for value transfer technology in new material development industry and the measurement technology of key parameter in key areas, as well as laying foundation in special detection method, improving the quality of industrial product and proposing improvement plan of overall technology, which is necessary for constructing the measurement support system and supporting the development of service industry. In this paper, calibration method of filter for linear beam smoke detector is studied, including attenuation value of light, uniformity of attenuation value, difference between positive and negative attenuation values. It ensures the effective traceability of filter for linear beam smoke detector and makes the work of smoke detection traceable.

Corrosion behaviors of the precursor glass (ZBLAN) of fluoride fibers in solutions of different pH values are studied. After seven d of corrosion, the infrared transmittance of ZBLAN decreases to almost 0 in acidic and neutral environments. However, there is no significant loss of transmittance in an alkaline environment. Similarly, the surfaces of the samples in acidic or neutral environments are severely corroded, whereas in alkaline environments, they are slightly corroded. In addition, it is found that samples corroded in neutral water have a complete crystallization phenomenon, wherein complex crystal phases emerged. However, no characteristic peaks of the crystal phase are observed in the samples corroded in the acidic and alkaline environments. The corrosion mechanism is investigated based on the change in the concentration of ZBLAN constituent elements in the solution via inductively coupled plasma (ICP) emission spectrometry.

We demonstrate the 4-stage and 8-stage silicon traveling-wave photodetectors (TWPDs) with inductive gain peaking technique. Compared with un-peaked TWPDs, the bandwidths of 4-stage and 8-stage TWPDs integrated with inductors are improved from 32 GHz to 44 GHz, and from 16GHz to 24 GHz, respectively. It is experimentally validated that gain peaking is an effective technology to improve bandwidths for multiple-stage TWPDs.

An original design approach for inverted tapers based on effective mode area (EMA) control is proposed. It has been demonstrated that the inverted taper with constant loss as a function of position along the taper is most efficient. First, a general equation which can satisfy this constant loss condition is derived between EMA and the position within the taper. EMA can be controlled by adjusting the waveguide width. Introducing the relationship between EMA and waveguide width into this equation, an optimal profile for the inverted taper is obtained. The design approach is illustrated by applying it to an ideal SOI inverted taper. The conversion loss of the designed inverted taper can be reduced by 60% and 78% compared to parabolic and linear inverted tapers, respectively, when the taper length is 300 μm.

Lithium niobate on insulator (LNOI) electro-optic modulator has broad application prospects in rapidly developing largecapacity and high-density coherent optical communication systems, due to its small size, ultra-high bandwidth and low voltage. However, the high coupling loss currently limits its practical application. In this paper, in order to realize efficient coupling property, we propose a high-coupling-efficiency bilayer inverse tapered spot-size converter (SSC) that can be integrated with an LNOI modulator. The spot-size converter consists of three parts: a double-layer inverse tapered waveguide in LNOI, a straight LNOI-based waveguide and a SiON waveguide. We mainly consider end-surface coupling efficiency, abrupt loss and transmission efficiency. The simulation results show that the total coupling efficiency of the chip to the lensed fiber with a mode-spot diameter of 3.2 µm can achieve to 97.51%/96.3% for TE/TM light at a wavelength of 1550 nm. The coupler shows high coupling efficiency and good polarization independence. The 3dB alignment tolerance between fiber and coupler is estimated as ±1.4 μm/±1.4 μm in X/Z direction for TE light, and ±1.45 μm/±1.3 μm in X/Z direction for TM light. Our coupler shows relatively large alignment tolerances that makes the optical packaging of the LNOI modulator more reliable. The proposed high-efficiency spot-size converter in this work is of great significance for realizing the practical application of LNOI modulators.

This system uses SOI optical waveguide ring resonator chip. By using the method of selecting single direction light path, we got the resonance curve and backscattering curve of the resonant, while the system is working under different light powers. The changing rules of FWHM and resonant depth under different light powers is analyzed. And the action mechanism of optical power on the cavity resonance curve and backscattering is analyzed. Finally, the optimal working optical power of SOI integrated optical gyroscope system is determined.

We demonstrate a single chip silicon-based optical single sideband (OSSB) modulator which is composed of a branch line coupler (BLC) and a silicon dual-parallel Mach-Zehnder modulator (DP-MZM). Benefit from the powerful tool of optical domain compensation we propose, the constrains such as power imbalance and phase offset of BLC are eliminated. As a result, we realize a fully functional OSSB chip to implement full carrier OSSB (FC-OSSB) and suppressed carrier OSSB (SC-OSSB) modulations. The maximum sideband suppression ratio (SSR) of 35 dB is derived at 21 GHz.

This article presents a graph-driven placement framework for Si photonic circuits. In this framework, a netlist exported from the schematic diagram is transferred into an adjacency matrix, and further parameterized to an undirected graph. By this method, optical devices and waveguides are quantified as nodes and edges, respectively. Non-Euclidean data structures between nodes can be extracted which includes parallel relations, sequential relations and connecting patterns, by matching those patterns with pre-defined database, certain layout strategies formulated by human experts can be properly applied. By extracting the geometric information and the preset spacing requirements of each device in the Process Design Kit library, the layout strategy requirements of each component can be assigned, so as to determine the geometric position. This work designed the graph-driven placement framework, tested the identification accuracy for connection pattern, and applied the framework in practical chip designs including artificial intelligent and Wavelength Division Multiplexing circuits.

A broadband TM-pass polarizer is proposed with the structure of graphene-incorporated rib-loaded LNOI waveguide. As graphene is a 2D material, it only brings loss to the optical mode with polarization direction parallel to graphene’s surface plane. By incorporating graphene onto the interface of LNOI platform and rib loading material, graphene mainly brings optical loss to TE mode. The proposed device can obtain high polarization extinction ratio ⪆40 dB while keep a low insertion loss < 0.5 dB to the TM mode. Since graphene has a wideband light absorption from visible to infrared, the working wavelength range of this device is broadband. The fabrication process of proposed polarizer is CMOScompatible, and it can be integrated into LNOI PIC. This polarizer can be applied for LNOI modulator and LNOI-based fiber gyroscope system.

With the development of integrated photonic circuits, optical waveguide microdisk resonators (MRR) devices which can be easily integrated with photonic chips are becoming more and more important in optical communication systems. As the core execution unit to improve response sensitivity, field-programmable gate array, optical waveguide MRR has high applicability in esonators due to its smaller mode volume, and larger free spectral range (FSR). Specially, SOI waveguide fabrication technology is easy to be compatible with CMOS foundry processing and integrated circuit technology with smaller size and lower cost, so it can overcome the shortcomings of micro resonators fabricated by other materials. And SOI waveguide MRR has important research significance and distinguished application prospects, which has considered to be the future large-scale integrated photonic circuit basic devices. Because of its powerful optical signal processing ability, MRR has been widely used in various optical systems. With the advantages of simple manufacturing process, ease integration, and multitudinous functions, the waveguide MRR has become the basic structural unit of integrated photonic system and considered as the basic device of large-scale integrated optical path. Based on the high thermo-optic (TO) coefficient of Si material, the tunable function of the SOI MRR can be realized by TO modulation. A waveguide MRR with large tuning range, low optical transmission loss, simple electrode fabrication method, and high TO efficiency is proposed. In order to enhance the applicability of the designed SOI waveguide MRR at different wavelength bands, a tunable SOI MRR was designed.

In recent years, in order to meet the urgent requirements of improving the volume-efficiency ratio of optical fiber inertial navigation components in various application fields such as sea, land, air and space, the integrated optical fiber gyroscope technology using optical chip integration and micro high-precision fiber coil has developed rapidly. As the sensitive core of integrated fiber optic gyroscope, the precision and reliability of micro high-precision fiber optic loop determine the precision and Technology maturity of integrated fiber optic gyroscope. This paper first introduces the basic composition of fiber optic gyroscope using optical chip integration scheme, then focuses on the micro high-precision fiber coil technology using multipole orthogonal winding and vacuum glue filling process, and creatively puts forward the reliability detection scheme of multi parameter fiber coil process. Through the multi parameter nondestructive testing technology, the manufacturing process defects of micro and small optical fiber coil are found, the manufacturing process is optimized, and an effective method to improve the process reliability of micro and small optical fiber coil is put forward. Finally, through the reliability accelerated test, the reliability improvement method of micro optical fiber coil process mentioned in this paper is verified. This paper has practical significance for the development and engineering application of integrated fiber optic gyroscope technology.

We report a phase modulation coherent linear phase demodulation (PM-CLPD) analog photonic link (APL) based on an optical phase-locked loop (OPLL). In this work, we mainly focus on the analysis for the impact of different noise sources on the noise floor in particular under different received optical powers. It was found that due to the limited commonmode noise rejection of the balanced detector, an appropriate received optical power should be made of choice in order to prevent the potential dynamic range deterioration. With this scope, experimental investigations have been carried to verify such specified condition at certain system configurations. In addition, to solve the problem of noise deterioration caused by optical amplification in traditional APL, a common optical amplification scheme is incorporated to facilitate the common-mode noise reduction, making the system less sensitive to the extra noise induced deterioration. By taking into account these aspects, an improvement as large as 10dB is demonstrated for the overall system noise floor.

Although silicon photonics (SiPh) has already been developed as a commercial technology, further improvements are under investigation to increase the yield in the volume production. Extinction ratio (ER) is one of the important characteristics of a SiPh Mach–Zehnder (MZ) in-phase and quadrature (IQ) modulator. Besides the chip design, waferlevel or chip-level testing becomes efficient for the ER yield improvement. Traditional method is useful in the measurement of single MZ modulators, but not accurate in that of IQ modulators. In this paper, a novel and effective ER measurement scheme for SiPh IQ-modulator is proposed, and investigated theoretically and experimentally. Compared to the convention method, our algorithm is still robust in SiPh modulator with extinction ratio larger than 45 dB, when the other child MZM is non-ideal and other noise exists. The well repeatability of the proposed algorithm is also demonstrated. The new ER measurement will be very useful in the wafer-level/chip-lever testing to increase the yield.

Based on the principle of geometric optics, we propose a design idea to realize the invisibility of three-dimensional objects. According to the electromagnetic characteristics of the material, the device modulates the scattered light of the invisible object and the parallel light emitted from the background of the device through the combination of two different materials and the structural design of the invisibility device. The invisible object is approximated as a cylinder, and its scattered light is approximated as a radial beam centered on the central axis of the cylinder. The invisibility device is designed based on the multi prism and modulates the propagation path of the light scattered from the object, so that the scattered light can be reflected many times in the device and avoid the detector which is in front of the device. Beside this, light ports are designed on both sides of the device, which can be used for the emission of the scattered light that scattered from any position of the object, so as to prevent the scattered light from becoming stray light after countless times of reflection and emitting at any position of invisibility device. In addition, assuming that the stealth device is in front of a uniform background with a single color, and the background light is approximately a parallel light, the device can also modulate the propagation path of the background parallel light. Through multiple refraction and reflection, the background light can bypass the invisible object and continue to propagate in the original direction as a parallel light, which can be detected by the detector. Through the combination of the two light path modulation, the effect that the detector can only detect the background light but not the scattered light of the object is realized, that is, the object is invisible. ZEMAX optical simulation software is used to simulate the light propagation path of the object scattered light and the background parallel light modulated in the invisibility device. The optical detector in the software simulates the real detector. The modulation effect and stealth effect of the invisibility device are analyzed through the detection data. The analysis shows that the design of the invisibility device based on the principle of geometric optics has a perfect modulation effect on the scattered light of the object and the background parallel light, and can realize the stealth of the macro three-dimensional object in the uniform background.

As the traditional life testing method is extremely time consuming, this paper proposed an accelerated life test method for LED source. The possible failure forms of LED chips are analyzed, and the causes are also discussed. A complicated accelerated life model is constructed in this paper and how to get the parameter is discussed. LED source high accelerated life testing platform is built to test the sample chips life, and different application of constant temperature and humidity mixed environment tests are used to stress the sample. The accelerated life model estimate parameter is obtained, and the life of sample LED chips is estimated by the model.

Chip-scale LiDAR is the critical component of unmanned platform. We present a single channel FMCW LiDAR integrated module including InP FMCW laser, silicon optical phased array and InP-based balanced photodetector, which achieving the function of multi-target ranging. The integrated chip size is 1.65cm×1.65cm. Coupling efficiency between on-chip laser and silicon waveguide is 62.8%. Common mode rejection ratio of balanced detector is 53.08dB. Ranging accuracy of integrated FMCW LiDAR is 8.82cm.

A multi-point self-coupling waveguide spectral shaper for on-chip computational spectrometer is proposed and verified by simulation. The autocorrelation coefficient of the spectral response of the filter has very narrow width of the main lobe, which helps to achieve a high resolution of the spectrometer. Due to the rich design degrees of freedom, each filter with can be designed to exhibit very distinct spectral characteristics, so that only 30 channels are adequate for accurate spectral reconstruction with 100 nm bandwidth and 2.5 nm resolution. Each filter has an ultra-compact footprint less than 4550.4 μm² and 30 filters in total occupy a footprint of about 0.13 mm².

The rapid development in portable and wearable electronics have stimulated the interest in the integrated energy storage devices. Flexible and transparent supercapacitors are responsible candidates for energy storage devices due to the high performance, quick charge/discharge and safety operation. Specially, it is a great challenge to fabricate transparent flexible electrodes serving as the critical component of supercapacitor. Herein, we constructure a novel and unique hierarchical nanopetal-structured MnO₂ on the freestanding metallic mesh framework as the supercapacitor electrode. The freestanding nanostructured electrode without substrate-supported shows highly transparent (~ 81.6%) and ultrathin thickness (~ 9 μm), moreover, the ultrathin thickness enabling the electrode with significant flexibility for further wearable systems. The as-fabricated nanostructured electrode provides a large surface area, which delivers an enhanced areal capacitance up to 24.8 mF/cm² that 2.5 times to the electrode without nanostructures. Additionally, the symmetric solidstate supercapacitors inherit the super-flexibility from the freestanding nanostructured electrode that enable the devices to be foldable and even crumpled into any objects. The solidstate supercapacitors can also maintain the long cycling stability of 99% retention after 10000 charge-discharge cycles, demonstrating high mechanical stability.

We demonstrate a 32-element silicon OPA chip with on-chip phase calibration. The on-chip phase calibration structure consists of interferometric structures and germanium silicon photodetectors (GeSi PDs). This structure can control any angle deflection within the scanning range without detecting the far-field patterns. In the horizontal direction, the on-chip phase calibration structure is used to achieve beam steering within the 36° scanning range, and the side-lobe suppression ratio can be close to 7dB.

Cryogenic Infrared Rays Focal Plane Array (IRFPA) detectors have been widely used in industry, transportation, security monitoring, meteorology and medicine because of the high sensitivity and temperature resolution. For HgCdTe IRFPA detectors, the typical working temperature is about 80 K. To make the IRFPA detector works at low temperatures, the detector should be integrated on a Dewar cold platform, whose refrigeration power would be higher than the heat load of the IRFPA. In general, the IRFPA detector and the Dewar cold platform would be integrated together to form a Dewar assembly at room temperature. In addition, the materials in IRFPA have different thermal expand coefficients, it means the thermal mismatch in the IRFPA would be an unavoidable issue in work. The thermal strain has a significant effect on the solder joints in switching cycle, which could lead to the creep strain and thermal fatigue crack. With the increase of the switch cyclic number, the creep strain and thermal fatigue crack under the thermal stress would lead to the failure of solder joints. Therefore, the low temperature thermal strain in switching cycle can affect the reliability of IRFPA detectors. So, the low temperature thermal strain and the creep lifetime of solder joints has been researched.

The influence of the driver frequency peaking on the coherent transmission system is carefully discussed in the study. It is found that the driver peaking can interact with its nonlinearity and the bandwidth of the modulator should be large enough to ensure that the peaking of the driver to be a moderate value.

We present a photonic based broadband DSSS system with photonic matched filter. The optical delay line and optical switch-based encoder/decoder is used in signal spreading/de-spreading. The simulation results show that the photonic matched filter could achieve fast acquisition of PN sequence.

Efficient optical coupling between standard single mode fibers and nanophotonic waveguides has been recognized as a major practical challenge since the early years of photonics. In this work, a low-loss and wide band edge coupler based on subwavelength gratings (SWG) for standard single mode fibers is proposed and demonstrated on 220 nm SOI platform. The edge coupler has a minimum feature size of 130 nm and a 630-m length, which was fabricated in CUMEC’s 200 mm CMOS production facilities. The best coupling losses are 1.60 and 1.95 dB for TE and TMin1500-1600 nm wavelength range, respectively, achieving a minimum PDL of 0.2 dB at 1500 nm. Moreover, by taking advantage of SiN-on-Si integrated process and wafer bonding process, the edge coupler exhibits high process and package reliability, making it attractive for the commercial application.

We present an improved 400G chip/device level Integrated Coherent Receiver (ICR) optical-electronic testing system based on the system last year [1]. It shows high repeatability and high accuracy compared with commercial system. This new system can greatly promote the efficiency, and it is also compatible for 100G/400G chip level test and device level test. What’s more, the system can get most of important parameters of ICR automatically.

The electrostatic discharge (ESD) effect and damage mechanism of Charge Coupled Device (CCD) is investigated. Transmission line pulsing (TLP) tests have been experimented to identify the instantaneous I-V characteristics of CCD detectors under ESD stress. The TLP I-V curves of the ports with or without ESD protection show different characteristics, which indicate that the electrostatic discharge is a capacitor charging process for the ports without protection. The ports with smaller capacitance such as the transfer clock and readout clocks are the weakness against ESD events. The electrostatic damage site is further analyzed using emission microscopy (EMMI) and Focused Ion beam technology (FIB), revealing that the electrostatic damage mechanism of CCD.

We propose an electric-arc based scheme to generate the intensity-controllable weak polarization mode coupling (PMC) points in polarization maintaining fiber (PMF). The PMC intensity can be readily controlled from -70dB up to -40dB. The insert loss introduced by the scheme is negligible since it does not need to break and splice the PMF.As an example, we demonstrated a piece PMF with three introduced PMC points as a quasi-distributed temperature sensor at last.

In the silicon-based devices, the third-order nonlinear effects containing Kerr effects, two-photon absorption (TPA), free carrier absorption (FCA) and free carrier dispersion (FCD) play the important role in the physical characteristics. In this paper, taking consideration of the linear and nonlinear effects, a comprehensive numerical analysis model based on the finite-difference-time-domain (FDTD) method is built and demonstrated. The nonlinear characteristics of the silicon-based waveguides and micro ring resonators are further discussed in the simulated results. The proposed model might provide an effective analysis method for all silicon-based devices, due to its good compatibility and accuracy.

With the development of LED technology and the innovation of shooting concept, the virtualized production technology based on LED curtain wall has attracted much attention in film and television creation. This technology uses the virtual imaging of the LED curtain wall as the shooting background to achieve real-time rendering and production. At the same time, the LED curtain wall, which is composed of multiple pixels, also has the lighting function. This paper summarizes the current lighting technology in virtual filming based on LED curtain wall and proposes solutions for the LED curtain wall’s visible distance and Moire pattern during filming.

Electron channeling contrast imaging (ECCI), as a rapid and convenient technique, has been widely used to characterize dislocations of heteroepitaxial III-V materials in recent years. The previous ECCI measurements, however, were primarily based on plan-view ones. In this work, we demonstrate an experimental observation of the cross sectional ECCI measurement on a Si-based GaAs sample for the first time. The plan view ECCI image can provide information on threading dislocations, stacking faults, as well as the dislocation distribution. By investigating the relationship between the defect contrast and the corresponding accelerating voltage, the optimal range of beam voltages for cross-sectional ECCI measurement is 10 kV-15 kV. The cross-sectional ECCI can simplify the process of characterizing dislocations in Si-based III-V materials.

Biomaterials are composed of biological particles, which are aggregated particle systems with complex spatial and fractal structures formed by smaller unit particles due to electrostatic forces, collisions, and adhesion. In this paper, the optical properties of aggregated particles were calculated based on optimized Ballistic Cluster-Cluster Aggregation (BCCA) model. The effect of different porosity and monomer numbers of aggregates on the absorption and scattering properties is investigated. The properties were found to be enhanced with decreasing porosity and increasing number of particle monomers. And it is also found that the error due to the randomness of the structure of the aggregated particles under the same conditions enables the above conclusion to be completely satisfied when the particle number difference is greater than or equal to 6.

Multicolor electrochromic materials and devices have been studied widely. However, typical electrochromic materials cannot be processed graphically, which limits their pixelation. This paper demonstrates a flexible pixeled electrochromic device formed by patterning the electrochromic layer though lithography technology. Under the directional exposure of the ultraviolet, the exposed region of the electrochromic material layer (light-curing electrochromic material based on the electro-acid mechanism) is cured into a film, which is directly realized as electrochromic materials patterning. In this paper, the patterned flexible large-area (100cm2 ) display device is successfully demonstrated with high optical contrast (~30%), in which the coloring and bleaching processes of a single pixel (16mm2 ) were 0.8s and 1s, respectively. Electrochromic material patterning can simplify the manufacturing process and realize display pixel, which opens a new way for the next generation of flexible and colorful electrochromic display devices.

We proposed an on-chip plasmonic anologue of electromagnetically induced transparency (EIT) with radiative and subradiant resonator side coupled to a metal-dielectric-metal(MDM) waveguide, theoretical and numerical simulation results show that this scheme can represent a three energy level EIT diagram in atomic system. A theoretical model based on coupled mode theory (CMT) is established to analyze the transmission spectrum of the structure, it agrees well with the FDTD result. The transparency peak can be achieved by adjusting the parameters of two resonators, and coupling strength can be adjusted by changing their gap width. The theoretical and simulation results can verify the PIT effects of resonator coupling based on surface plasmon polaritons (SPPs) and may provide a reference for highly integrated optical circuits.

The wide band-gap of two-dimensional (2D) MoTe2 makes it impossible to directly detect terahertz waves. In this paper, a planar THz antenna-based 2D MoTe2 detection structure is proposed for THz detection. Numerical study shows that the designed and optimized double bow-tie Au planar antennas structure achieves extremely strong terahertz wave coupling in a narrow band at 0.1THz, and the absorption reaches 99.99%, and the enhanced local field distributed in central region of antennas. The absorption of the double bow-tie antennas is 1.3 times than that of the single bow-tie antennas with the same main structure parameters. When combine the double bow-tie antennas with 2D MoTe2, 0.1THz wave was detected by them under a small bias applied on the antennas. The carriers among the detector are brought about by the injected electrons from the Au antennas by the electromagnetic-induced well. The experimental results show that the detection structure has good ohmic characteristics, and the detection responsivity is 0.02mA/W, and the specific detection rate is 4.67×10 5Jones. This kind of antenna-based 2D materials terahertz wave detector can easily adjust detection wavelength by changing structure parameters of antennas, which has potential applications in terahertz detection technology.

Two-dimensional (2D) layered materials have aroused widespread interests due to their remarkable physical characteristics such as strong light-matter interaction and layered-dependent physical properties. Molybdenum disulfide (MoS₂), one of the group of transition metal dichalcogenides (TMDCs), has many great applications on photoelectronic devices. Herein, based on high carrier mobility of graphene, a vertical graphene/MoS2 van der Waals heterostructure photodetector was designed and fabricated. With help of gap between graphene and MoS2, the responsibility of our device (7219 A W-1 at 532 nm) is better than that of MoS2 photodetector. As a transistor, on-off ratio of our device can be ~194. The results show the graphene-based heterostructure can provide numerous help for improving the performance of 2D photodetectors and transistor

Spectral Beam Combination (SBC) technology is an effective way to obtain high power laser beam. Polarization independent multilayer dielectric grating (MLDG) with high damage threshold, high diffraction efficiency is one of the key elements of SBC. In order to effectively combine more laser beams，the wavelength range of grating needs to be broad. To the best of our knowledge, 1480 line/mm is the highest reported line density to date. But its bandwidth is only 35nm. In this paper, we designed broadband polarization independent multilayer dielectric gratings of 1480 lines/mm for spectral beam combination. And the grating is designed to work at the -1 st order Littrow mounting for the central wavelength of 1053nm. Based on the theory of Rigorous Coupled Wave Analysis (RCWA), a multilayer dielectric film grating is established. Ta2O5 (n=2.08) and SiO2 (n=1.46) are used as a high and low refractive index material to form the high reflectivity mirror of (HL)12 H structure. The influence of the number of MLDG groove layers on the bandwidth is mainly analyzed, including single -layer, double-layer, three-layer, four-layer and five-layer. Then, we find that increase the number of groove layers can increase bandwidth of MLDG. And polarization-averaged diffraction efficiency of the grating with five-layer groove was greater than 95% in the wavelength range of 1003 -1083nm (80nm). In addition, the design parameters, tolerance analysis of the grating grooves are described.

In ultra-precision machining, the precision displacement measurement system is required to ensure the positioning accuracy of the tool and the work-piece, and then to ensure the processing accuracy of the product. The grating displacement measurement system which adopt grating pitch as measurement reference not only has big measurement span and high-resolution advantages but also has strong anti-interference ability. So it is widely used in performance testing of surface processing equipment. The traditional two-dimensional grating measuring system realizes two-dimensional measurement by installing two one-dimensional grating measurement devices in two directions of the two-dimensional platform. It’s easy to introduce the abbe error in this way and obviously a lot of space is occupied. While the micro-displacement measurement system based on the two-dimensional grating can not only obtain the micro-displacement data information of two directions at the same time, but also has high measurement accuracy, small abbe error and compact structure. Two-dimensional grating is the core component of the two-dimensional grating measurement system. In this paper, the design two-dimensional grating is carried out. In the case of vertical incidence of the He-Ne laser with 632.8 nm wavelength, we develop the microstructure design of two-dimensional aluminum-plated and gold-plated grating with periods of 1 micron and 2 microns. Based on the rigorous coupled wave theory (RCWA) and Rsoft software, the following simulation results are obtained. Two-dimensional grating with period of 1 micron has higher diffraction efficiency compared with period of 2 microns. When the duty cycle between 0.43-0.58 and the groove depth between 140nm-200nm, the diffraction efficiency of two-dimensional aluminum grating with period of 1 micron is more than 18%. Although the diffraction efficiency of two-dimensional gold grating with period of 1 micron can also achieve 18%, its tolerance range is very small.

In this study, we theoretically propose a surface plasmon resonance (SPR) biosensor composed of a plasmonic gold film, double negative (DNG) metamaterial, graphene-MoS2−COOH Van der Waals heterostructures and gold nanoparticles (Au NPs). We use a novel scheme of Goos-Hänchen (GH) shift to study the biosensing performances of our proposed plasmonic biosensor. The calculation results show that, both an extreme low reflectivity of 8.52×10^-10 and significantly enhanced GH sensitivity of 2.1530×10⁷ μm/RIU can be obtained, corresponding to the optimal configuration: 32 nm Au film/120 nm metamaterial/4-layer graphene/4-layer MoS₂−COOH. In addition, there is a theoretically excellent linear response between the concentration of target analytes (SARS-CoV-2 and S protein) and the change in differential GH shift. Our proposed biosensor promises to be a useful tool for performing the novel coronavirus detection.

A method for solving bimetallic film coefficients using surface plasmon resonance (SPR) phase difference experimental data with fixed wavelength and multiple incident angles is presented to simplify and quickly solve the thickness and optical constants of metal films in this paper. The purpose is to extract unknown parameters from the phase difference between P- and S- polarizations of the reflected light occurred at the metal/dielectric interface. The results of bimetallic layer film’s thickness and optical constants obtained by our method are in better agreement with that of spectroscopic ellipsometer (SE) measurement method. Therefore, the approach reveals the possibility of retrieving the thickness and optical constants from the measurement results of the phase difference for multilayers, and makes it be a much better option to be employed for further film’s parameter analysis applications

In order to obtain accurate nano-film characteristic parameters in the ellipsometry measurement process, an optimization algorithm for solving the thickness and complex refractive index of nano films by spectroscopic ellipsometry is proposed. An improved adaptive genetic algorithm (IAGA) has been proposed to process nano-film data, this method combines the evolutionary algebraic attenuation factor with the adaptive genetic algorithm. It can solve the problem that the genetic algorithm is premature and easy to fall into the local optimization. The algorithm is used to calculate the film parameters of silicon dioxide nano film thickness standard template with standard value of 49.7±0.4 nm in this paper. The results show that the relative error of the calculation results of the film thickness is less than 3%, and the error of refractive index is less than 0.1. At the same time, it is verified by experiments that the IAGA algorithm model can effectively optimize the number of iterations, and has the advantages of fast convergence speed and high measurement efficiency.

Exceptional points (EPs) are special state points in a non-Hermitian system, at which both the eigenvalues and the eigenstates of the system coalesce. The parameter space around it often presents peculiar physical phenomena, such as greatly improved sensitivity. In this paper, a non-Hermitian metasurface based on patterned graphene in the terahertz frequency range is designed. Its unit cell consists of a pair of orthogonally oriented graphene split-ring-resonators with different geometries, which makes it a non-Parity-time (PT) symmetric system. The existence of the EPs is further confirmed by the coincident eigenstate polarizations and eigen transmission exchange behaviors. This work provides a basis platform for studying EP points in a graphene metasurface.

In the context of the rapid development of information society, the mainstream von Neumann computing systems have bottlenecks in power consumption and computational efficiency, which restricts the development of artificial intelligence with massive data as the core. Neuromorphic computing which follows the working mode of the human brain breaks through this bottleneck. However, with the increasing demand for the amount of data processed by the computing systems, the computation of electrical neurons and synapses based on electrical signals fails to meet the demand gradually. At this time, the emergence of neuromorphic computing in the field of photonics is expected to solve this problem. In this paper, an all-optical synaptic directional coupler based on phase change material Ge₂Sb₂Se₄Te₁ (GSST) is proposed. The coupler controls the coupling length of the two waveguides by applying a 1200 nm laser pulse and changing the number of crystal GSST islands in the hybrid waveguide to achieve weight variation. The switching energy consumption of the GSST optical-switch is only 0.025 nJ, and the corresponding switching speed reaches the nanosecond level. The functions of long-term enhancement (LTP) and long-term suppression (LTD) based on GSST optical synapse can be realized simultaneously, providing new ideas for future low-power non-volatile photonic integration.