The Internet is a collection of interconnected Autonomous Systems (ASes) that use the Border Gateway Protocol (BGP) to exchange reachability information. In this regard, BGP stability and scalability in the inter-domain scope have been matters of major concern for many years, and network engineers have been applying several techniques to cope with these issues. BGP is also used intra-domain (internal

The correlation between electrical properties and surface plasmon resonance (SPR) wavelength was discussed using ITO grating coupler. ITO films were prepared on SiO\(_{2}\)/Si substrate by RF sputtering with thermal annealing, and the grating was directly fabricated on the sample surface by focused ion beam. Electron density and mobility were evaluated by fitting optical reflection spectra according

In Elastic Optical Networks (EONs), the way different service demands are supported in the network is ruled by the Routing, Modulation and Spectrum Assignment (RMSA) algorithm, which decides how the spectrum resources of the optical network are assigned to each service demand. In a dynamic EON, demand requests arrive randomly one at a time and the accepted demands last in the network for a random time

We developed a modulation code using a complex amplitude and established a method to demodulate the code based on a convolutional neural network (CNN) for holographic data storage. The developed 20:9 modulation code consists of nine symbols, each of which contains 4 bits of data representing the symbol position on which the complex amplitude is superimposed and 16 bits of data representing the actual

A computer-generated moiré profilometry based on flat image demodulation is proposed. A sinusoidal fringe pattern and its background light are modulated by two-frequency carrier fringes, respectively, to combine a composite grating. While this composite grating is projected onto the measured object, the composite deformed pattern can be captured by CCD camera. So the sinusoidal deformed pattern and

We propose colors light detection and ranging (LiDAR) using visible laser diodes (LD) of red, green, and blue (RGB) colors to identify colors as well as obtain position information of surrounding objects. To verify the principle, we performed round-trip time-of-flight (TOF) measurements by irradiating a target of different colors with pulsed light from a LD of RGB colors. It is clarified that accurate

A plasmonic planar lens operating at terahertz (THz) region based on InSb micro-slit array with varying dielectric slit width is designed and numerically investigated. Dielectric slits provide desired phase retardations of beam manipulating with varying phase propagation constant. Taking advantage of the permittivity thermo-tunable property of InSb, the focal spot of this lens can be actively controlled

A measurement system based on the Scheimpflug principle is designed in this paper to solve the problem of difficulty in clear imaging due to excessively small depth of field in line-structured light close-range photogrammetry. A conversion model from the image coordinate system to the measured object coordinate system is established through the spatial projection relationship. The calibration method

In Software-Defined Networking (SDN), the control and data planes are decoupled, leading to a more programmable and efficient network management. In this paper, the controller placement problem in SDN is addressed, jointly with the problem of exploring a high-availability tree subgraph, in order to support delay and availability requirements between the switches and the controllers. We consider that

The response of light in a nonlinear dispersive medium is governed by the nonlinear Schrödinger equation (NLSE). In general, for higher order group velocity dispersion (GVD) with frequency-dependent gain or absorption, NLSE is numerically solved using the split-step Fourier method. Extended NLSEs including the effects of higher order GVD, frequency-dependent gain and frequency-dependent absorption

We have previously presented a blood perfusion parameter by means of the spatial contrast of speckle patterns observed for blood perfusion in skin tissue and a blood vessel. This parameter permits us to visualize a relative blood perfusion distribution from a single speckle pattern. Therefore, it can estimate the blood perfusion with a frame rate of an imaging device employed. This parameter is, however

The interdependence between communication networks, e.g., an optical backbone network, and power grids is a critical issue to take into account when designing and operating both systems. In fact, failures in one network may cause further failures in the other network and vice versa. This is because nodes in power grids (i.e., power generators, loads or interchange nodes) are controlled and managed

We propose a layout estimation method for multi-layered ink using a measurement of the line spread function (LSF) and machine learning. The three-dimensional printing market for general consumers focuses on the reproduction of realistic appearance. In particular, for the reproduction of human skin, it is important to control translucency by adopting a multilayer structure. Traditionally, layer design

To reduce the effect of atmospheric turbulence and stabilize the optical link in free-space optical (FSO) communications, we have proposed to use an optical duplicate system (ODS) as a multi-beam generator. In this paper, a transmitter adopting the ODS is designed and constructed for the experiment. Moreover, the experiment is conducted to transmit multi-beam generated by the ODS between two points

Polarization is useful for estimating surface normals. In this paper, polarization is applied to shape estimation. Surface normal estimation from a single image is commonly performed by shape-from-shading. An alternative approach is shape-from-polarization, which usually cannot uniquely determine the surface normal and must be accompanied by additional information. The shading information is a promising

Based on a Nd:LaMgAl11O19 (Nd:LMA) disordered crystal, we have experimentally demonstrated a diode-pumped high-repetition-rate Q-switched laser, which can operate at 1056, 1083 nm, or 1056 and 1083 nm, respectively, using a SF6 prism to adjust the cavity loss. For the three states, the characteristics of the Nd:LMA laser including the average output power, pulse width and frequency repetition rate

Remote visual testing by video cameras is the standard process for inspecting the pressure vessel of nuclear reactors. The inspectors need to find stress corrosion cracking of around several tens of µm wide on a display monitor observed by remote wired cameras in the reactor pressure vessel filled with cooling water. The inside surface of the vessel structure has typically been blasted or grinded during

We demonstrate a single-shot uniaxial 3D profilometry system that illuminates a sample with a structured polarization pattern and measures the reflected full-Stokes polarimetric image. Some non-contact 3D measurements require evaluating samples located in a protected environment. For example, this may be a sample under the lid of an acrylic Petri dish, a sample that has a protective film overlay, or

In this study, a simple hollow core hexagonal structured photonic crystal fiber is offered and analyzed to discern commonly used different type of alcohols in our daily life. The proposed sensor guiding properties are numerically investigated using a full vectorial finite element software-based scheme. To ensure higher accuracy, the properties of alcohols (refractive index and dielectric constant)

In this paper, we propose the design of a survivable energy-efficient and crosstalk-aware routing, spectrum, and core allocation (RSCA) scheme for online multiclass traffic in both spectral and temporal domains in SDM-EON. Multipath based protection scheme is applied to ensure survivability against single link failure. Advanced reservation (AR) connections being a part of multiclass traffic may withstand

We propose, and experimentally demonstrate, an SDN (Software Defined Networking) new management solution for legacy GPONs (Gigabit Passive Optical Networks), which allows users to dynamically control their residential networks by means of a management application. In this way, users can customize the allocation of resources (and set constraints, if desired) to connected devices in their residential

In this letter, the high-order harmonic generation (HHG) of wurtzitic and hexagonal boron nitride (h-BN) under ultrafast intense laser field was studied by solving an extended multiband semiconductor Bloch equations (SBEs). The results showed that for both the wurtzitic and hexagonal structures, the cutoff energy of the HHG was extended linearly by increasing the field strength, and the efficiency

Based on the probability density function of the composite channel considering Malaga atmospheric turbulence, pointing error and atmospheric path loss, the asymptotic expressions of channel capacity and outage probability for binary phase shift keying (BPSK) modulation system are derived using Meijer G function. The numerical results show that under the same intensity of turbulence and path loss condition

Orbital angular momentum (OAM) beams have orthogonality between them, which can greatly increase the capacity of a communication system, but an OAM multiplexed communication system will be affected by atmospheric turbulence during transmission, which will cause channel crosstalks. In this paper, we adopt the blind equalization algorithm, which can recover multiple signals with blinding source separation

We have provided two compact designs of on-chip silicon photonic crystal (PhC) AND and XOR logic devices, which can provide multiple logic functions through different input frequencies within one structure. Compared to the former ones, the overall size is short to 10a × 18a (approximately 4 × 8 μm2). The working principle of the structures is lead to the directional leakage of the center cavity and

In this work, the polarized beams tightly focused through a cylindrical refractive-indices discontinuous dielectric interface was numerically investigated. The corresponding focal pattern calculation formula was deduced base on vectoral diffraction integration theory for the first time. The patterns through the cylindrical dielectric interface with different radii were revealed by numerical calculating

We have developed a new high-speed driving circuit of a multi-color LED panel by the use of FPGA for subjective super-resolution display. In the subjective super-resolution display, the coded display image is switched and displayed at high speed. The viewer makes an unconscious correction by fixational eye movement and perceives the resolution higher than the physical number of pixels of the LED panel

The design requirements of the Fourier transform optical system required for synthetic aperture radar(SAR) are analyzed and the specific optical parameters are determined. The design of the Fourier lens adopts a fully symmetrical structure to avoid simultaneous optimization of the forward and reverse directions of the optical path and can complete the correction of the conjugate positional aberrations

This work deals with dimensioning of wireless mesh networks (WMN) composed of FSO (free space optics) links. Although FSO links realize broadband transmission at low cost, their drawback is sensitivity to adverse weather conditions causing transmission degradation on multiple links. Hence, designing such FSO networks requires an optimization model to find the cheapest configuration of link capacities

We developed a network architecture called information-centric elastic optical transport network (i-CEON) that enables efficient content delivery. Increasing the volume of video traffic consumes network resources, so it is necessary to establish optical transport network architectures suitable for content delivery. For this purpose, we extend existing information-centric networking to be applicable

A novel structure for photonic frequency-multiplication millimeter-wave (mm-wave) generation with two cascaded dual-parallel Mach–Zehnder modulators (DPMZMs) but no optical filter is demonstrated. By properly adjusting the phase and amplitude of radio frequency (RF) driving signal and the bias points of two DPMZMs, frequency 12-tupled, 18-tupled, or 24-tupled high-spectral-purity mm-wave signals are

We propose a highly doped circular photonic crystal fiber (HDC-PCF) in which solid fiber core is surrounded by four layer circular rings consisting of air holes in the cladding. The condition of flattened dispersion and very low confinement loss has been achieved by introducing air-filled circular tiny defects in the core region. When we designed a defected core HDC-PCF by introducing one, two, three

This work considers the joint problem of securing confidential demands against eavesdropping attacks and protecting the network against link failures in elastic optical networks (EONs). Network coding is used to provide security for confidential connections by encrypting the data through XOR operations at the physical layer with other established connections in the network. Backup paths are also computed

Using the finite element method, we numerically investigated the transient behavior of molecular orientations of a liquid crystal (LC) lens with a circular electrode beside a hole-patterned electrode and a common flat electrode that has a resistive film. The transient properties of a three-dimensional electric field and the molecular orientations of the LC were simultaneously calculated when voltages

In this paper, we present the evaluation of a predesign of a zoom system based on a variable-focal-power lens by paraxial and aberration analyses only. This zoom system involves less mechanics and has a more compact design than those using a fixed-power lens. We derive corresponding formulas between the focal power of each lens and the magnification of the zoom system, and the bendings of the variable-focal-power

In this paper, we propose a full duplex architecture based on a hybrid link composed of free space optics (FSO) and multimode plastic optical fiber (MMPOF) for short-range wireless access networks. The proposed architecture employs mode group division multiplexing (MGDM) and wavelength reuse techniques to transmit data between central unit (CU) and radio access units (RAUs). An optical frequency comb

This work presents optimization algorithms on attack-aware routing and spectrum allocation (Aa-RSA) in conjunction with spectrum selective switch (SSS) placement, taking into account variations in traffic demands. The objectives of the algorithms are to minimize the required number of SSSs, as well as the number of lightpath re-allocations between different demand scenarios, taking into account the

Optical networks are vulnerable to failures due to targeted attacks or large-scale disasters. The recoverability of optical networks refers to the ability of an optical network to return to a desired performance level after suffering topological perturbations such as link failures. This paper proposes a general topological approach and recoverability indicators to measure the network recoverability

Importance of simultaneous measurement of temperature and strain by fiber Bragg grating (FBG) sensors has led to innovation of several renewing techniques. Most of them are based on two FBGs configurations or one non-uniform FBG implementation. Both temperature and strain changes can result in Bragg wavelength shift in reflected spectrum from a uniform FBG. We propose using full width at half maximum

Reconfigurable optical networks have emerged as a promising technology to efficiently serve the fast-growing traffic produced by the digital society. This paper provides a survey of the field. We first review enabling optical hardware technologies in general and then consider technologies that are specific to data center networks and wide-area networks in more detail. We further provide an overview

In this paper, we propose a cost-efficient single mode fiber-free space optics (SMF-FSO) based hybrid \(32 \times 2~\text{Gbps}\) wavelength division multiplexed passive optical network (WDM-PON) employing optical frequency comb (OFC) source and polarization multiplexing. OFC source is realized at optical line terminal (OLT) by modulating a single continuous wave (CW) laser source with radio frequency

We have realized a novel optical system to form a large aerial image in front of a full-color LED panel that is covered with retro-reflector. The retro-reflector has square apertures through which lights from the LED pixels pass. Our optical system is based on aerial imaging by retro-reflection (AIRR). The aerial image formed with AIRR is visible over a wide viewing angle without using 3D glasses.

Issues of high energy costs and a time delay factor currently pose a considerable challenge to the success of the Internet of Things (IoT). Accordingly, fog computing (fog-C) has been introduced as a new paradigm to address both the high bandwidth cost and time delay issues that can result from transmitting sensing data all the way to centralized cloud servers. In addition, the optical fog-C network

In this study, the effects of selectively yellow-cut lenses on contrast sensitivity were investigated in healthy young and middle-aged individuals and elderly patients with cataract. Contrast sensitivity in middle-aged healthy individuals and elderly patients with cataract was higher when measured while the subjects were wearing selectively yellow-cut lens (NeoContrast; Mitsui Chemicals, Inc., Tokyo

Sound evokes sub-nanoscale vibration within the sensory epithelium. The epithelium contains not only immotile cells but also contractile outer hair cells (OHCs) that actively shrink and elongate synchronously with the sound. However, the in vivo motion of OHCs has remained undetermined. The aim of this work is to perform high-resolution and -accuracy vibrometry in live guinea pigs with an SC-introduced

For several decades, optical networks, due to their high capacity and long-distance transmission range, have been used as the major communication technology to serve network traffic, especially in the core and metro segments of communication networks. Unfortunately, our society has often experienced how the correct functioning of these critical infrastructures can be substantially hindered by massive

A three-dimensional (3D) shape measurement method based on speckle-embedded fringe patterns (composite fringe patterns) and wrapped phase-to-height lookup table (LUT) is proposed. As an auxiliary signal, speckle is embedded into the phase domain of the projected fringes, and the wrapped phase and deformed speckle modulated by the objects are demodulated by phase-shifting algorithm. With the assistance

The demand for high bandwidth on the Internet is growing drastically, and one of the solutions for tackling this problem is using optical networks. Burst switching is one of the techniques that can be used in optical networks to handle high traffic. Aside from the many advantages that this technique has, it suffers from a big flaw called burst contention. Optical burst switching (OBS) is a switching

A reconfigurable and application-specific tunable microwave photonic filter having finite impulse response is proposed. The filter exploits the differential mode group delays of linearly polarized modes in a multi-mode fiber to achieve single and multiple high-frequency passband response. The filter taps are realized using a single continuous wave laser source and differential delays among modes that

Ultrasonic wave has been widely used in the medical field because of its special physical properties. However, it might cause health risk for the human body if the power is inaccurately measured. As a noncontact measurement method, the acousto-optic method gives a lower uncertainty than the mechanical and contact method. To improve the accuracy of ultrasonic power measurement system based on the acousto-optic

In mode-division multiplexing systems, the transmission quality is restricted by the differential mode delay (DMD). We previously proposed a spatial mode exchange technique using volume holograms (VHET) to reduce the DMD. VHET can be used for the exchange of multiple spatial modes with different transmission speeds using a single device. However, in VHET, incidents of cross-talk (XT) caused by non-target

In this study, the effect of the shift in the refractive index between two dispersive elements on the output phase-conjugated (PC) wave power of waveband-shift-free optical-phase conjugators based on difference-frequency generation (DFG-OPCs) is analyzed. First, a numerical model of the DFG-OPC is built by considering the shift ∆n in the refractive index. The derived formula shows that the output PC

A low-noise and fast optical encryption method for three-dimensional (3-D) information using the double-phase method is proposed. First, the 3-D information is encoded into a phase-only hologram (POH) by the angular-spectrum diffraction and the double-phase method. Second, the chaotic random phase mask (CRPM) is generated by the hybrid logical map and the iterative chaotic map with infinite collapses

An Upper Physical layer functional Split (UPS) for an Ethernet fronthaul network is modelled, and the frame delay and Frame Delay Variation (FDV) limitations are investigated. The results show that contention in Ethernet switch ports can cause an increase in the delay and FDV beyond proposed specifications for the UPS and other time-sensitive traffic types such as I/Q-type traffic. Time Aware Shaping

Terahertz (THz) waves are a promising candidate for detection, imaging, and advanced communications with ultrafast transmission speed. To develop THz technologies, miniaturized devices for controlling THz waves are essential. In this study, a high-performance vanadium dioxide (VO2)-based switchable band-pass metamaterial integrated with a silicon substrate for THz waves is designed and fabricated.

We studied the mechanism causing the fluttering-heart illusion in which the motion of an inner figure appears unsynchronized compared with that of the outer figure surrounding it although the motion of both figures is objectively synchronized in reality. Experiment 1 examined the effect of edges’ luminance contrasts. The illusion was measured under conditions where the luminance contrasts of the outer

Elastic Optical Networks (EONs) are extensively accepted promising solution for future ultra-high-speed optical transmission, due to their capability of efficient and flexible assignment of immense optical bandwidth to the heterogeneous traffic demand. However, it undergoes through an aggravated form of the spectrum fragmentation problem due to the heterogeneous bandwidth requirements, spectrum continuity

This paper proposes a static Routing and Spectrum Allocation (RSA) method to design low-power elastic optical networks. In the elastic optical networks, data are transmitted via lightpaths, which are routes flexibly assigned frequency resources according to transmission distances and traffic demands. When designing the elastic optical networks with a static lightpath establishment policy, lightpaths

Speckle contrast of single, dual, and triple emitter broad area laser diodes (BA-LDs) with a wavelength of 638 nm was experimentally investigated. Speckle noise was relatively small near the threshold current probably due to the longitudinal mode competition. Higher output power led to smaller speckle noise owing to the spectrum widening. A wide stripe presented an advantage in terms of speckle reduction

A novel spectroscopic optical sensor is presented for cancerous cell detection in various parts of the human body (i.e., cervix, adrenal gland, breast, skin, and blood). An optimized structure based on compact cladding is successfully designed with enhanced sensitivity and very low confinement loss. The parameters like effective area (Aeff), V-parameter (Veff), spot size (Weff), numerical aperture