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This work proposes a new energy efficient method for generating two mutually coherent laser lines. This method combines mutual optical injection locking with external modulation, which can be implemented with an electro-absorption modulator (EAM). Numerical simulations demonstrate that the proposed method is feasible within a narrow locking range. In addition, it is demonstrated that suppressing the optical carrier of the modulated signal extends the locking range by a factor of 3. [ABSTRACT FROM AUTHOR]

With the increasing demand for high-speed wireless connectivity, Optical Wireless Communication (OWC) links are gaining traction as a promising solution. Semiconductor Optical Amplifiers (SOAs) can play a key role in OWC systems by providing optical gain to overcome channel losses. In this paper, we present the design and evaluate the performance of SOAs tailored for usage in OWC links. The SOA is based on a Gallium Arsenide (GaAs) material system and fabricated using molecular beam epitaxy. This paper describes, for the first time, the planning associate degreed optical modulator numerical simulations from semiconductor optical-electronic equipment injected at forty gigacycle frequencies or higher into a fiber-optic loop that has been electronically modified by a microwave carrier. The device is optically modulated up to sixty gigacycles despite the employed SOA model having a gain recovery time of>1.6 ns. As a result of a total gain, recovery isn't required. The interferometry device was shown to have higher performance than the SOA alone. At the same time, it is also possible to perform optical modulation, sampling, and intermixture or be used simultaneously as a modulator (uplink) and electronic equipment (downlink) in analog links. Simulation results indicate a peak gain of >20 dB can be achieved with low noise figure (<5 dB) for input signals up to 10 Gbps. The SOA exhibits good linearity and gain saturation properties at frequencies up to 5 GHz, with >15 dB gain and <8 dB noise figure. Overall, the results demonstrate the potential of the designed SOA to act as a preamplifier for OWC applications with data rates on the order of Billions of Bits per Second Gbps. [ABSTRACT FROM AUTHOR]

The demand for high transmission rates and dependable communication drive the optical Multi-carrier modulation technique to be an appealing method owing to its broad spectrum particularity. In this paper, hybrid optical OFDM is evaluated and discussed for LOS and NLOS channel models. The perfect signal shaping characterized by optimal biasing and scaling at the transmitter/receiver sides within the optical power limitations plays a significant role in system performance. Consequently, the minimum needed energy bit/noise bit (Eb/N0) to preserve a required bit-error rate is achieved for a selected multi-layer modulation system and a specified variety of optical power limitations. Simulation results demonstrated the minimisation of the BER could be obtained by reducing the ambient noise vai adopting an extra process stage at the receiver, notably, at the transmitter side. The outcomes were presented in terms of two channels. Upon utilising the identical bit rate of all scenarios, we have found that the equalisation could enhance the overall system performance with MMSE values outperforming the ZF equaliser by SNR of 5 dB at the specific bit-error-rate of 0001. [ABSTRACT FROM AUTHOR]

For this research article, we have investigated 3.84Tbps DWDM long-haul system for the performance enhancement by mitigating the fiber nonlinearities using Gaussian Filters and various modulation formats viz. RZ, MDRZ, DRZ, CSRZ and RZ-DQPSK. The comparative performance analysis has been made to discover the best modulation format for 2400 km transmission distance with and without using Gaussian Filters (GFs) at transmitting end before compounding and receiving end after de-compounding. The performance of the purposed system is measured in respect of Q-factor, BER, Eye diagrams and OSNR (Optical Signal to Noise Ratio) for 1st and every 8th channel using symmetrical dispersion compensation technique at 0dBm input power with 50 GHz frequency separation between adjacent channels. Using GFs at both ends, the system performance is enhanced with RZ-DQPSK followed by CSRZ and DRZ modulation formats in comparison to MDRZ and RZ which proved the former formats as much resilient and robust against nonlinear degradation factors with average OSNR of more than 37 and 36 dB having highest Q-factor of 12.45, 8.93 and 8.25 with corresponding smallest BER values of 6.61719e−036, 1.6859e−019 and 6.45976e−017 respectively. [ABSTRACT FROM AUTHOR]

A rapid growth of wireless communication system has boosted the exponential development on smart technology while driving a substantial increase in traffic volume. With a highly congested and demand on RF bandwidth spectrum, Visible Light Communication (VLC) seem as a complementary technology towards RF based system which provide wider bandwidth, free and unregulated channel, poses no health hazard, high security and low power consumption leads VLC to be one of the promising technology in data transmission. By maintaining the main purpose of illumination, the exploitation on the existing LED-based lighting system is used as a transmission mechanism to photodetector or image sensor which is used to detect the variations of the light intensity via free space optical channels. Different VLC modulation schemes is review in this paper to see the pros and cons of each scheme implemented in outdoor application specifically for vehicle-to-vehicle (V2V) VLC system. Various type of noises is presented in this paper with the denoising scheme to eliminate or reduce the shot and thermal noise caused by natural sunlight and artificial roadside infrastructure light which degrades the performance of VLC system. [ABSTRACT FROM AUTHOR]

By reviewing the recently available data, there's no evidence found for the adverse impact of LED emission on human life by daily use (lights and screen display) by the ordinary person with keeping the benefits of using LED lighting. There are some facts available that when exposed to glow in late hours of the day, inclusive ofLED lights or monitor, may have a significant impact on our circadian system, although there's not enough evidence which will prove that this aggravation of the circadian mood prompts unsafe impacts on human well-being. it's seen that Children have similarly high affectability to blue light in spite of the very fact that the emanation probably won't be so hurtful, radiations running within the middle of 400nm to 500nm which are utilized in toys, appears very dazzling and may cause photochemical retinopathy, which may be a serious issue for youngsters up to three years, old people also experience discomfort when exposed to rich blue light. thanks to te mporal light modulation (flickering) in some LED has potential health concern at a frequency about 100hz and above. Since the utilization of LED remains gradually increasing, so its important to watch the adverse impact on human life from an extended time exposure to LED. [ABSTRACT FROM AUTHOR]

The KM3NeT Collaboration has developed a multi-PMT optical so lution for construction of the two deep-sea ARCA and ORCA telescopes. This approach has several advantages compared to the single-PMT optical modules which have been traditionally used in neutrino telescopes, including a larger photocathode area which is equivalent to three 10-inch photomultipliers. In addition, the multi-PMT approach allows for a high resolution, good positioning and timing calibration. The integration of the optical modules follows a strict protocol and a standardised procedure. It takes place in parallel at eight different integration sites in the labs of the collaboration. In this way, it is possible to reach a significant production rate of more than 100 well-qualified modules per month. In this proceeding, we present details of the technology of the KM3NeT optical module and the integration process. [ABSTRACT FROM AUTHOR]

Magnesium fluoride (MgF2) single crystal has been widely used as a material for application in optics due to its excellent properties like birefringence, wide range of transparency and low refractive index. As such, MgF2 has been proposed for planar waveguide structures. Ion implantation method was frequently used for planar waveguide production due to its ability to modulate optical properties by introduction of impurities and defects in crystal lattice. In all optics fabrication processes, there are demands for a precise control of optical characteristics modulation and hence the need for precise distribution of implanted impurities and induced damage. In this study, 4 MeV C3+ ions with the fluence of 5×1015 ions/cm2 were implanted in (001) axial direction of MgF2 single crystal. In order to determine the damage depth distribution in the crystal sample, photoluminescence (PL) spectroscopy was proposed as a method of evaluation. PL spectroscopy was used as a convenient method for damage investigation of transparent and semi-transparent samples. The cross-section of the implanted zone was mapped with the step of 0.34 µm and the variations in the spectra were investigated. It was shown that intensity evolution of two prominent wide bands with the intensity maximums at about 590 nm and 733 nm can be used for damage depth distribution estimation. Comparing the relative changes of derivatives of the band's intensities, data related to the damage depth distribution were obtained. Obtained distribution was compared with the SRIM calculation of displacement damage. Considering the difference in implantation direction, good agreement with SRIM results was obtained. As a consequence of ion channeling, it was shown that damage distribution is extended deeper (for about 20%). [ABSTRACT FROM AUTHOR]

The properties and characteristics of test signals used in constructing the high definition TV (HDTV) and ultra-high definition TV (UHDTV) become an essential task. The proposal was made for the properties and different parameters of tool signals. These properties were considered very important to estimate. the spatial two-dimensional transfer function of frequency modulation through the light path of test signals. Some work was also performed to measure the resolution of the signal transmission and the end device. [ABSTRACT FROM AUTHOR]

In passive optical networks (PON), the signals are transmitted using the optical line terminal (OLT) in the head station and the optical network units (ONU) on the subscriber side. In this optical part of the network, the system performance can be limited either by the losses or, assuming that the link is not limited by the source or detector speed, by the dispersion of the fiber. Nevertheless, other important limiting factors on network performance are: the efficiency of optical transducer in optical transmitter in converting input radiofrequency currents into optical power modulations and the efficiency of receiver in converting optical power modulations into radiofrequency output current. Determination of the moderating influence of conversion modules efficiency on link parameters is the main task PON designers. [ABSTRACT FROM AUTHOR]

In this paper, we experimentally demonstrated a novel all-optical reservoir computer with an all optical input mask. The combination of the binary random masks and the time-stretched ultrashort pulses has increased the system's classification performance. Compared with the traditional digital masks, this method shows superior classification performance in spoken-digit classification tasks and eliminates the need for high-speed modulation for digital masks. [ABSTRACT FROM AUTHOR]

We report the first application of the Machine Learning technique of data-driven dominant balance to optical fiber noise-driven Modulation Instability, with the aim to automatically identify local regions of dispersive and nonlinear interactions governing the dynamics. We first consider the analytical solutions of Nonlinear Schrödinger Equation – solitons on finite background – where it is shown that dominant balance distinguishes two particularly different dynamical regimes: one where the nonlinear process is dominating the dispersive propagation, and one where nonlinearity and second order dispersion act together driving the localization of breathers. By means of numerical simulations, we then analyse the spatio-temporal dynamics of noise-driven Modulation Instability and demonstrate that data-driven dominant balance can successfully identify the associated dominating physical regimes even within the turbulent dynamics. [ABSTRACT FROM AUTHOR]

We report experimental results of a frequency shifted digital holography setup for spatially resolved vibrometry. A spatially homogeneous artificial phase modulation is used as a reference to correct for speckle noise. Furthermore, when superimposed upon the object vibration with slightly different frequency, the resulting beat can be evaluated. The beat frequency is invariant under relative motion between the object and interferometer, providing robustness in presence of parasitic low-frequency vibrations. In addition, the 'working point' is raised out of the noise floor, providing the opportunity to enhance the sensitivity at small vibration displacements. The method is demonstrated by measurements on a vibrating clarinet reed. [ABSTRACT FROM AUTHOR]

In the present work, we describe the synthesis and electrochromic (EC) properties of electrode material made of zinc oxide (ZnO) nano-pebbles. Highly ordered nanocrystalline nanoporous ZnO nano-pebbles electrode with crystalline hexagonal structure was synthesized on the ITO coated glass substrate using RF magnetron sputtering in a reactive atmosphere (Ar:O2::2:3) at room temperature (RT). The EC behavior of the active electrode was analyzed using UV-Vis spectroscopy and cyclic voltammetry (CV). The cyclic Voltammogram revealed the highly reversible redox characteristics with good cyclic stability at least upto 500 cycles. The proposed architecture, {Glass/ITO/ZnO nano-pebbles/1MKCl/ITO/glass} was found to be electrochemically active and exhibits wide optical modulation (26%), high reversible process, and good cyclic stability. The cathodic coloration ZnO electrode may be a potential candidate for novel and cheap energy efficient device and provide the indoor comfort with financial benefits. [ABSTRACT FROM AUTHOR]

Metasurfaces made of arrays of vertically aligned semiconductor nanowires are suitable platforms for light management in optical and photonic applications. Here we report a design approach aimed at engineering the optical behavior of semiconductor nanowire ensembles randomly displaced on the substrate, in order to enhance modulation effects in their optical reflectance response. By resorting to analytical and numerical simulations we demonstrate that the combined implementation of a multi-shell layering together with a tapered designing on the individual nanowire offer new opportunities to tailor the optical reflectance oscillations in this kind of architectures. The simulation insights were compared to experimental results reported for self-assembled GaAs nanowires and GaAs/AlGaAs core-shell nanowires. The proposed approach is especially promising for epitaxially grown semiconductor nanowires, where the suggested design modifications can be easily implemented during the nanostructure growth. [ABSTRACT FROM AUTHOR]

This paper describes a fiber extensometer system that utilizes pulse width modulation in its light source for power efficiency reason. The fiber extensometer was used to monitor displacement by intensity modulation techniques based on macro bending effects. The fiber extensometer consisted of an Arduino microcontroller; to modulate laser sources into optical pulses and to regulate data transmission; a bent fiber for displacement sensor, detector and amplifier, GSM module, antennas and power supply system which was solar cell based. The ON - OFF pulse timer from the programming using the C + language in the Arduino sets the pulse time difference ON - OFF of laser light. The modulated light was then launched to the sensor fiber, received and amplified by detector system. When displacement occurs, the diameter of the fiber bent will change as well as the sensor output. Furthermore, the microcontroller instructed the GSM module to send the output signals contain information about displacement to the user's mobile phone in the form of short message service (SMS). It was obtained that power savings that can be achieved using pulse width modulation techniques on this fiber extensometer system reached 30%, compared to that of fiber extensometers that used continuous laser. [ABSTRACT FROM AUTHOR]

We demonstrate an optical induced switching of the optical properties of metal-organic frameworks soaked in advance in 1,4-dioxane, and dimetholeformamide. Near-infrared laser pulses stimulate reversible and fast blue shift of the absorption band of the framework. Such light-induced switching enables the remote modulation of optical properties of metal-organic frameworks and opens up the possibility of utilizing them for all-optical data processing. [ABSTRACT FROM AUTHOR]

This work focuses on fabricating a solid electrolyte Ta2O5 thin film deposited by cathodic arc plasm (CAP) deposition through three different ratio of oxygen and argon. In our experiments, refractive index of Ta2O5 films are taken as 2.25, 1.96, 1.9 with various O2/Ar= 1.5, O2/Ar= 2, O2/Ar= 2.4, respectively. Our results show that the refractive index mostly decreased as we increase the oxygen flow rate, in which the minimum is found at 240 sccm. It provides good conduction pathways for ions through smaller thin-film's refractive index that exhibits more porosity voids. This property enhances ion's mobility for electrochromic device causing rapid coloring/bleaching phenomenon. Ta2O5 thin film is suitable as a solid electrolyte layer in center of electrochromic device (ECD) using CAP deposition. As a result, rapid response times were observed in fabricated device with an area of 5 cm×5 cm, exhibiting transmittance optical modulation ΔT = 61.5% (@550 nm) with the bleaching time τ = 8 s and transmittance optical modulation ΔT = 50% (@550 nm) with the coloring time τ= 10 s. [ABSTRACT FROM AUTHOR]

The Baikal-GVD neutrino telescope in Lake Baikal is intended for studying astrophysical neutrino fluxes by recording the Cherenkov radiation of the secondary muons and showers generated in neutrino interactions. The first stage of Baikal-GVD will be equipped with about 2300 optical modules. We describe the design of the optical module, the front-end electronics and the laboratory characterization and calibration before deployment. [ABSTRACT FROM AUTHOR]

UV light processing presents a facile means to tailor the properties of materials and structures. Metal-organic framework (MOF) with strong optical response has been realized through the incorporation of luminescent ligand within the van der Waals structure. The resulting MOF exhibits a significant one-photon excited luminesces change in response to UV light, enabling spatial modulation of the luminescent map of the MOF in micrometer scale. It thus demonstrates the capacity of patterning and data storage inside the crystal in a high resolution. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate ultrafast all-optical modulation in periodic arrays of subwavelength gallium arsenide nanodisks with localized Mie-type resonances. The efficient laser pulse modulation of up to 90% on the picosecond scale in the vicinity of the magnetic dipole resonance at a low pump fluence below 400 µJ/cm2 is shown by transient reflectance spectroscopy. [ABSTRACT FROM AUTHOR]

Identification of a dynamic model of a Mach-Zehnder amplitude optical modulator with parasitic phase modulation is discussed. An algorithm for identification is proposed and validated in an experiment. [ABSTRACT FROM PUBLISHER]

Electric field sensing using LiNbO3 polarization interferometers, acting as optical retarders, has been demonstrated in previous works. A polarization interferometer is implemented by an birefringent optical waveguide, which is constructed on a Z-cut-Y propagating LiNbO3 crystal. However polarization interferometers are quite sensitive to optical polarization, which results in DC-drift of the sensed signal at the output. To minimize the DC-drift of the electric field sensing, unbalanced LiNbO3 Mach-Zehnder interferometers can also be used. Such a device is inherently polarization insensitive when constructed on an X-cut Z-propagating LiNbO3 crystal. Either the polarization or the unbalanced interferometers introduce optical delays, which can be modulated by the sensed electric field. At the output of the optical retarders the variations of the electric field are imprinted on the optical delay variations. To recuperate the electric field information, optical demodulation is achieved by introducing a second optical delay, which is matched to the sensor's optical delay. In this paper a description of the two types of optical retarders, when used as electric field sensors is presented. [ABSTRACT FROM PUBLISHER]

Free Space Optical Communication become more and more popular due to its advantage over Radio Frequency Communication. In this paper BER and Q-factor is observed at different parameters. It is observed that BER is increased with increase in distance and Q-factor is decreased with increase in distance. BER and Q-factor is also affected by Bit Rate and Divergence. If Bit rate and Divergence is increase BER will increased and Q-factor is decreased. It is observed that with Mach-Zehnder optical modulator we get a BER of 10−20 at a distance of 1.8 km with bit rate 2.5 Gbps and Q-factor 30 is achieved at a distance of 1.6 km with 2.5 Gbps bit rate. [ABSTRACT FROM PUBLISHER]

A mechano-optical modulator is presented based on the Integrated Optical Nano-Mechanical (IONM) effect [1]. It consists of a light-weight, rigid silicon-nitride suspended plate structure with strengthening ridges and bi-directional electrostatic actuation to maximize switching speed. The mechanical structure and optical waveguide are realized on separate chips and then assembled together resulting in hybrid integration. The latter is made possible by using a self-alignment technique which results in a misalignment error of at most 2 μm. [ABSTRACT FROM PUBLISHER]

The authors give an overview of experimental results on 10.7 Gbit/s data transmission over large-core  1 mm polymethylmethacrylate (PMMA) polymer optical fiber (POF). Different modulation schemes like non-returnto- zero modulation (NRZ), pulse amplitude modulation (PAM) and discrete multitone modulation (DMT) are investigated. The obtained results show that eye-safe data transmission (0 dBm at 680 nm) between 2 m to 20 m stepindex POF (SI-POF) or 15 m to 35 m graded-index POF (GI-POF) can be achieved depending on the complexity of signal processing used. [ABSTRACT FROM AUTHOR]

A comprehensive analysis of the up-conversion capability of mode-locked laser diodes as photonic oscillators is presented in the context of fiber-wireless links providing high-speed access in the 60 GHz band. The properties of photonic millimeter wave generation are studied and compared through simulation and experiment. Data transmission can be shown in an externally modulated link for BPSK, QPSK and 16QAM modulation formats and data rates up to 4.234 Gbps. [ABSTRACT FROM PUBLISHER]

Self-Phase Modulation (SPM) can not be ignored in single light source OFDM system, so it is necessary to overcome the influence of SPM. A joint equalization solution to optical OFDM system based on orthogonal wavelet transform is proposed in this paper. In this method, block pilots are periodically inserted into the frame of OFDM signals. At receiver, the phase rotations of pilots are extracted to pre-compensation. Then, Maximum Likelihood Sequence Estimation (MLSE) equalizer based on Voterra is applied to compensation the SPM. Simulation results demonstrate that the proposed method is effective for 100 Gbit/s optical 16QAM-OFDM system in which the G.652 fiber with nonlinear coefficient of 2.6 /w/km is used. [ABSTRACT FROM PUBLISHER]

Ultra-Wide Band radio-over-fiber (UWBoF) techno-logy involves two kinds of communications. One is the UWB wireless communication, and the other is optical fiber communi-cation. In this paper, the UWBoF receiving system based on the external modulation such as Mach-Zehnder (M-Z) modulator is analyzed. The UWBoF components and the UWBoF receiver structure are introduced. The received high frequency UWB signal by UWB antenna has been transformed into the low frequency which could be fit the frequency requirement for the RF port of the M-Z modulator. The electronic signal can be transformed into the optical signal and transmit in optical fiber by M-Z modulator. Firstly, the characteristics of M-Z modulation are analyzed in theory. Then the half-wave voltage and the modulation output spectrums characteristics of the UWBoF receiving system have been tested. The testing results show that the output spectrums characteristics are consistent with the theoretical analysis. [ABSTRACT FROM PUBLISHER]

A novel multifunctional 60-GHz-band radio-over-fiber(RoF) system based on a Dual-Parallel Mach-Zehnder Modulator (DPMZM) is theoretically investigated and simulated. In this scheme, downlink signals of the 60GHz optical-wireless signal generated by means of subcarrier-multiplexing (SCM) technique to carry 2.5Gb/s differential phase-shift-keying(DPSK) by the 30GHz local oscillator in central station(CS) and 10GHz wireline baseband signal are simultaneously transmitted; the 60GHz remote local oscillator(LO) signal for down-conversion of uplink radio frequency(RF) signal is generated; and the uplink data of 1.25Gb/s baseband signal transmission is realized by remodulation of downlink DPSK signal without the need of additional light source is realized. Thus the configuration of base station(BS) in full-duplex RoF systems is simplified and the cost is saved. The simulation system is set up to testify the transmission performance of these signals. The signals with multiple services are successfully transmitted over 30km single-mode fiber. [ABSTRACT FROM PUBLISHER]

In the free space optical communication (FSO), the optical signals transmitted in the open air link .Inevitably, the signal received are influenced by atmosphere disturbance noise, so the reliability of FSO system is reduced. The present paper analyzed the principle of modulation and demodulation of PolSK and studied its main properties, then analyzed the performance of communication system by simulation experiments. [ABSTRACT FROM PUBLISHER]

This paper presents a multi-target distinguishing method for Frequency modulated Continues Wave (FMCW) Ladar, which is based on velocity compensated rang-doppler decoupling method. The multi-target distinguishing method could be used to detect targets within same range and different speed, and could also be used to detect high speed targets. Simulation results prove the validity of this method, and show that it could extend speed range of FMCW Ladar system and achieve high detection resolution. [ABSTRACT FROM PUBLISHER]

Polarization shift keying (PolSK) is a new modulation technique, it uses the state of polarization of an electromagnetic wave carrier as the information bearing parameter. This paper describes a modulation/demodulation method based on PolSK, and a high-speed laser communication system, and verifies its feasibility through theoretical analysis and computer simulation. Studies have shown that the based on the parameters of laser polarization modulation and demodulation techniques have unique advantages, such as in anti-atmospheric interference, higher data rate and lower bit error rate, greatly improving the reliability of communication. In addition to polymorphism modulation can be achieved by this modulation method, which has a data capacity. In the future, the PolSK modulation and differential demodulation method has a broad space for development and application prospects in the space laser communications. [ABSTRACT FROM PUBLISHER]

We propose a digital method to asynchronously monitor optical modulated signals. It allows the recovery of the eye diagram with a number of samples down to 212 without significant impairment due to the method. An embedded implementation of the algorithm based on a hybrid hardware and software solution is proposed. [ABSTRACT FROM PUBLISHER]

In comparison with conventional semiconductor optical amplifier (SOA) intensity modulators in intensity modulation and direct detection (IMDD) passive optical network (PON) systems, quantum dot SOA intensity modulators can considerably improve the transmission performance of optical orthogonal frequency division multiplexed (OFDM) signals, broaden the optimum operating condition ranges, and allows a 10dB reduction in continuous (CW) optical input power injected into the modulators for achieving signal bit rates more than 30Gb/s over 60km single mode fibers (SMFs). [ABSTRACT FROM PUBLISHER]

Frequency Modulated Continuous Wave (FMCW) Ladar features in high range resolution, small range ambiguity and is capable of acquiring high resolution 3D image. When detecting a moving target, , FMCW Ladar could achieve the target's range and speed information by using Range-Doppler decoupling method, and image the target field in 4D style. This paper describes the principle of FMCW Ladar, analyzes the shortage of traditional Range-Doppler decoupling method, and presents an improved Range-Doppler decoupling method which is based on velocity compensation. Simulation results have shown that the new method could effectively extend no fuzzy speed of FMCW Ladar, and achieve high precision of target range and speed at the same time. [ABSTRACT FROM PUBLISHER]

To realize a high-speed and high-capacity transmission link for fast mobile vehicles such as a bullet train, we propose a wavelength-division-multiplexing radio-on-radio-over-fiber (WDM-RoRoF) system with a linearly located distributed antenna system (DAS) on the 90-GHz band. All the conventional microwave (MW) radio signals such as mobile telecommunication and broadcast signals are encapsulated in a single millimeter-wave (MMW) carrier radio. Centralized control at a central office using the information of the position of a car can optimize and distribute the suitable RoRoF signal to each remote cell over optical fibers. An optical two-tone generator with an optical modulator can easily generate a 90-GHz RoRoF signal, and then, a high-speed photomixer directly converts from an RoRoF signal to an MMW RoR signal, which is composed of an MW signal with a 90-GHz carrier component, for irradiation over air. Heterodyne frequency down-conversion performs the direct frequency conversion from the MMW signal to an MW signal available to consumers. [ABSTRACT FROM PUBLISHER]

In this article, a novel architecture for full duplex wired and wireless network with optical fiber backbone network is proposed. We employ a dual drive dual port Mach-Zehnder modulator to simultaneously modulate the CW laser source with wired and wireless data, for the downstream link. Light remodulation technique using RSOA is utilized in the upstream link to provide a reliable bidirectional optical channel. WDM is used to further increase the capacity of the system. Simulation of the proposed scheme demonstrates a 2.5 Gb/s wired and wireless downlink datastream and 1 Gb/s uplink. [ABSTRACT FROM PUBLISHER]

We propose a decoy-pulse protocol for frequency-coded implementation of B92 quantum key distribution protocol. A direct extension of decoy-pulse method to frequency-coding scheme results in security loss as an eavesdropper can distinguish between signal and decoy pulses by measuring the carrier photon number without affecting other statistics. We overcome this problem by optimizing the ratio of carrier photon number of decoy-to-signal pulse to be as close to unity as possible. In our method the switching between signal and decoy pulses is achieved by changing the amplitude of RF signal as opposed to modulating the intensity of optical signal thus reducing system cost. Our simulation results show a key generation rate of 1.5×10−4/pulse for link lengths up to 70km. Finally, we discuss the optimum value of average photon number of signal pulse for a given key rate while also optimizing the carrier ratio. [ABSTRACT FROM PUBLISHER]

An intelligent approach to establishing link parameters of importance in the optical wireless channel is proposed. A genetic algorithm (GA) is used to perform a selection technique for the link parameters with minimal cost. An artificial neural (ANN) network then adapts the channel with the best fit of learning sets. The objectives include an attempt to exploit the power of hybrid intelligent systems in the outdoor optical wireless channel and a prediction of a reliable adaptation technique that contributes to best possible bit-error-rate (BER) under certain weather conditions and link characteristics. [ABSTRACT FROM PUBLISHER]

This paper presents our method of contrast enhancement and evaluation of the Optical coherence tomography (OCT) images using subjective and objective, Average gray level, indices of image quality metrics. Subjective assessment has been widely used due to high confidence and simplicity. However, extensive experience is required in subjective evaluation and it is affected by inconsistence. A good objective method represents future paradigm. Both methods have their own merits and demerits. This paper is to (1) present the most fundamental indices of measuring image quality through subjective evaluation and objective measures; (2) recommend objective metrics that are proportional to subjective measure and represent the expert understanding. [ABSTRACT FROM PUBLISHER]