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The present contribution aims to build chiral Cosserat effective models of architectured media prone to such effects, recoursing to dedicated homogenization methods. In order to develop a method in full generality, the effective Cosserat model is obtained from the degeneration of the micromorphic effective continuum, by projecting the micromorphic kinematic degrees of freedom onto the Cosserat variables. The proposed homogenization method relies on variational principles and a decomposition of the microscopic displacement into a so-called homogeneous part and a periodic fluctuation. The homogeneous contribution to the total microscopic displacement accounts for the postulated effective generalized continuum, and it is corrected by a displacement fluctuation. The energy of the fluctuating displacement is shown to define a measure of the accuracy of the homogenized chiral Cosserat model. Applications of the proposed homogenization framework are done for centrosymmetric and non-centrosymmetric chiral architected media.

International audience; Polymer composites of molecular spin crossover complexes have emerged as promising mechanical actuator materials, but their effective thermomechanical properties remain elusive. In this work, we investigated a series of iron(II)-triazole@P(VDF-TrFE) particulate composites using a tensile testing stage with temperature control. From these measurements, we assessed the temperature dependence of the Young's modulus as well as the free deformation and blocking stress, associated with the thermally-induced spin transition. The results denote that the expansion of the particles at the spin transition is effectively transferred to the macroscopic composite material, providing ca. 1–3% axial strain for 25% particle load. This strain is in excess of the ‘neat’ particle strain, which we attribute to particle-matrix mechanical coupling. On the other hand, the blocking stress (∼1 MPa) appears reduced by the softening of the composite around the spin transition temperature.

A Doppler shift estimation system with relatively high dynamic range is conceived and demonstrated. The scheme is based on dual mixing the modulated radar echo and frequency to voltage mapping. Hence, it needs no radio frequency auxiliary part. This makes the system capable of becoming integrated into any photonic radar, which would positively affect the cost and size of such system. Since the mixing procedure is all-optical, the system is able to identify the Doppler frequency of a radar echo with carrier frequency as high as 40 GHz independent of its amplitude. The system dynamic range can be as high as 42 dB at 10-GHz radar carrier with an acceptable error of 5%. This dynamic range was achieved using lock-in amplification technique.

Antilock braking systems require accurate vehicle speed and acceleration estimations from wheel speed sensors. Adaptive Kalman filtering is used to estimate wheel speed and acceleration for each wheel. Single core or multicore processor-based embedded systems perform the required estimation using a two-stage extended Kalman filter in many clock cycles, which limits Kalman filter speed and accuracy. In the proposed system, purely arithmetic operations used in the process are simplified and implemented as embedded logic to reduce the overhead delays and increase the update rate by 48%. The proposed system is run sequentially using finite-state machines, while a large number of multiplication and division operations are removed through rewiring and logic reuse. The simplifications not only reduce the amount of logic required to perform the operations by 39.7% but also use simple logic, which can run faster than the replaced logic on field-programmable gate array. The results presented show comparable root-mean-square wheel speed error with a high update rate of 20 MHz when running on a 50-MHz board in all scenarios. The system also provides accurate wheel acceleration estimation, which is crucial for many systems, including the reference system.

A study was performed on the University Link and Northgate Link projects in Seattle, WA, to investigate the use of apparent density evaluation methods for the identification of air pockets and plugging issues in the chamber of EPB TBMs. Both air pockets and plugging issues can result from improper soil conditioning and the TBM’s inability to mix the soil properly with the conditioning agents. An apparent density below unity indicates the formation of an air pocket in the top part of the chamber and an apparent density above the virgin soil density points to developing plugging issues in the cutterhead bays and pressurized chamber. From the conducted study it can be concluded that the presented apparent density evaluation methods are an effective way to identify issues in the excavation chamber of an EPB TBM and can be used as a mean to improve the soil conditioning process.

A Doppler shift measurement system based on four-wave mixing effect in a highly nonlinear fiber is demonstrated practically. The system exhibits two low-frequency voltages, which are functions of the Doppler shift, and therefore, low-cost low-frequency photodetectors can be employed in the system. No sophisticated electrical instrument is required to perform the measurement. The scheme is able to simultaneously and independently measure the Doppler frequency of a radar echo and its power level with carrier frequency up to 40 GHz. The system is suitable to be employed in any microwave photonics (MWP) radar system with broad frequency agility characteristics or the other MWP systems operating based on frequency hopping technique.

5G communications require a multi Gb/s data transmission in its small cells. For this purpose millimeter wave (mm-wave) RF signals are the best solutions to be utilized for high speed data transmission. Generation of these high frequency RF signals is challenging in electrical domain therefore photonic generation of these signals is more studied. In this work, a photonic based simple and robust method for generating millimeter waves applicable in 5G access fronthaul is presented. Besides generating of the mm-wave signal in the 60 GHz frequency band the radio over fiber (RoF) system for transmission of orthogonal frequency division multiplexing (OFDM) with 5 GHz bandwidth is presented. For the purpose of wireless transmission for 5G application the required antenna is designed and developed. The total system performance in one small cell was studied and the error vector magnitude (EVM) of the system was evaluated.

An improved sensitivity Doppler frequency measurement system based on microwave photonics technology was demonstrated practically. The system employs a four-wave mixing effect to achieve broad radio-frequency (RF) frequency measurement. In addition, a lock-in amplification technique was utilized to achieve high-measurement sensitivity. The system is, thus, capable of Doppler frequency estimation of radar echoes with a carrier frequency up to 40 GHz and a power level as low as $-$ 35 dBm.

A standalone microwave photonics system for Doppler frequency measurement purposes is conceived and demonstrated practically. The system exhibits a maximum of 1.61% relative error in Doppler frequency estimation at the worst case. Utilization of all optical mixing has enabled RF frequency independent operation. The system is thus capable of operating at any radar carrier frequency up to 40 GHz. This makes it a perfect candidate for various types of photonic-based radars and frequency agility systems.

The statistical analysis of the RMS delay spread is achieved based on the results obtained from an outdoor time-varying ultra-wideband (UWB) channel measurement. The paper reports on the RMS delay spread values, the cumulative distribution functions (CDFs) and the probability density functions (PDFs) for the measured channel configurations with their estimated parameters. Findings show how the RMS delay spread values are fluctuating for different channel configurations within the same measurement campaign. For example, 35 ns and 2.5 ns have been obtained for different channels. The differences in the measured instantaneous RMS delay spread leads to obtaining different PDFs that fit the measured data where Generalized Pareto distribution is dominant. The relation between the RMS delay spread and the channel path loss has been studied. Positive correlation is seen for all measured channels with different amounts. The highest correlation value is 0.7675 while the lowest is 0.2951. The coherence bandwidth analysis is also conducted, and the values are fluctuating as the case of the RMS delay spread. The obtained values varies between 325.3 MHz and 5.7 MHz.

Generation of dual-wavelength using passive semiconductor microring resonator with two sections of apodized grating with total length of 26 µm on the right and left sides is presented here. In this research we use the timedomain travelling wave (TDTW) method to model and simulate the microring resonator made of InGaAsP/InP waveguide. Microring resonator based optical mirrors and band-limited reflectors have been the subject of intense investigations in recent years. Therefore, we propose the microring resonator made of InGaAsP/InP waveguide having two sides grating section. The grating sections have a trapezoidal profile. The gratings provide the means to suppress repetition of the reflection spectrum at every free spectral range (FSR) removed from the design wavelength. The total grating length is 26 µm (each grating side has length of 13 µm), where the total circumference of the microring resonator is 526 µm. Propagation of the input Gaussian pulse (with 10 mW power and bandwidth of 0.76 ps) within the grating sections is presented, where it shows a good confinement of the propagation within the waveguide. As a result, multiple dual-wavelengths with tunable spacing within a range of 127 pm (15.8 GHz) and 237 pm (29.6 GHz) could be generated at the throughput port of the microring resonator. The dispersion of the grating section versus the total grating length and the frequency response of the throughput port output signals are presented. The generated dual-wavelength has many applications in optical sensing, radio frequency (RF) radiation, optical communication, optical switching, millimetre wave generators and biological research.

The performance of soft-ground tunnel boring machines can be significantly impacted by soil abrasivity. During the last decade, several soil abrasion testing systems have been developed to characterize abrasivity of various soil mixes in different conditions. This article discusses the comparison between the results of a Soil Abrasion Test (SAT) developed by Stiftelsen for Industriell og Teknisk Forskning (SINTEF)/Norwegian University of Science and Technology (NTNU) and the Soil Abrasion Index (SAI) testing system developed by the authors. The reason for this comparison is the availability of SAT results for a few tunneling projects that were constructed in recent years. Obtaining any relationship or correlation between the SAI and SAT will allow the use of some of the machine field performance data to evaluate the ability of SAI in predicting the wear on these machines. The study of SAT has been conducted on the testing device designed and fabricated based on the original specifications of NTNU. The study was designed to evaluate the sensitivity of the SAT testing system to some of the controlling parameters and testing procedures as compared to the SAI test. This article summarizes the result of a series of specially designed tests to evaluate the impact of various testing parameters on SAT results as well as a comparison of the results between the two tests.

A microwave photonics instantaneous frequency measurement receiver was conceived and practically demonstrated. The system is based on phase modulation inside a Sagnac loop and therefore needs no bias voltage, resulting in no DC bias drifts. The system provides a DC output whose amplitude is a function of input signal frequency, and thus no high-frequency photo-detector is required. Furthermore, the system exhibits a very good sensitivity without the aid of any sort of electrical noise cancellation techniques, such as lock-in amplification. This makes the system response faster, which would be another benefit for electronic warfare applications. Less than 6% measurement error was achieved over a 0.01–40 GHz frequency range for −30 dBm RF level. Also, a 10% error was achieved at −51 dBm RF power level.

A system of an add-drop microring resonator integrated with a sampled grating distributed feedback (SG-DFB) is investigated via modeling and simulation with the time-domain traveling wave (TDTW) method. The proposed microring resonator comprises a SiO2 waveguide integrated with an InGaAsP/InP SG-DFB, and the SiO2 waveguide consists of a silicon core having a refractive index of 3.48 and Kerr coefficient of 4.5 × 10-18 m2/W. The SG-DFB consists of a series of grating bursts that are constructed using a periodic apodization function with a burst spacing in the grating of 45 μm, a burst length of 5 μm, and 10 bursts across the total length of the SG-DBR. Transmission results of the through and drop port of the microring resonator show the significant capacity enhancement of the generated center wavelengths. The Q-factor of the microring resonator system, defined as the center wavelength (λ0) divided by 3 dB FWHM, without and with integration with the SG-DFB is calculated as 1.93 × 105 and 2.87 × 105, respectively. Analysis of the dispersion of the system reveals that increasing the wavelength results in a decrease of the dispersion. The higher capacity and efficiency are the advantages of integrating the microring resonator and the InGaAsP/InP SG-DFB.

We demonstrate a widely tunable dual-wavelength erbium-doped fiber laser that used a 10-cm photonic crystal fiber as a Mach–Zehnder interferometer to filter out the switchable dual-wavelength signals so as to generate tunable continuous-wave (CW) terahertz (THz) radiation. Each single longitudinal mode wavelength could be independently tuned by using a tunable band-pass filter and polarization controller (PC). The wavelength fine-tuning was achieved via adjustments to the PC, and the resulting dual-wavelength output had a side-mode suppression ratio (SMSR) of more than 30 dB. The wavelength spacing of 7, 11.4, and 21.2 nm, corresponding to 0.9, 1.4, and 2.66 THz radiation, respectively, was tuned in order to obtain CW THz radiation. This CW THz radiation was produced by means of a stable dual-wavelength fiber laser performing as the optical beat source, together with a DAST crystal-based photomixer. High-sensitivity thermal sensors calibrated for THz radiation were able to continuously detect the emitted CW THz radiation.

We demonstrate a stable tunable dual-wavelength erbium-doped fiber laser generated by launching a mode-locked laser into an add–drop microring resonator. Two silicon-based high-index-contrast microring resonators with $Q$ -factors of 1.2 × 10 5 and 0.6 × 10 5 have been used as add–drop filters independently. As a result, multiwavelength generation was achieved and demonstrated both theoretically and experimentally with free spectral range (FSR) of 0.202 and 0.404 nm corresponding to the microrings' diameter of $\textrm{D}=2.54$ and $\textrm{D}=1.27\,\mbox{mm}$ . A high-resolution tunable bandpass filter and fiber Bragg gratings (FBGs) are then used to extract a tunable and switchable dual-wavelength coherent source from the generated multiwavelength coherent source. Subsequently, the dual-wavelength coherent source with tunable FSRs from 0.404 to 3.232 nm is achieved and presented. The obtained dual-wavelength output has a side-mode suppression ratio of more than 30 dB.

Mode-locked optical carriers with applicability for radio over free space optics (RoFSO) systems have been produced via a ring laser cavity incorporating an add/drop filter. This technique of generation allowed for servicing of a greater number of channels in a wavelength-division multiplexing RoFSO system, and the carriers were able to travel in a free space channel with very little dispersion. Sixteen carriers, having a free spectral range (FSR) of 12.5 GHz and full-width at half-maximum (FWHM) of 250 MHz, were created. Eight of these 16 generated carriers were then separately modulated with eight orthogonal frequency-division multiplex signals and subsequently optically multiplexed and transmitted to a free space optic (FSO) channel using an FSO antenna. At the receiver side, the received signal was demultiplexed, and the performance of the system was analyzed via calculating the error vector magnitude and constellation diagram of the entire system.

A system of soliton array (SA) for optical communication using the wired/wireless link is presented. Gaussian laser beam with relevant parameters is input into the rings system. Here, bright soliton with Full Width at Half Maximum (FWHM) and Free Specrum Range (FSR) of 120 ps and 370 ps are generated respectively. We demonstrate that SA can be obtained by a series of micro ring resonators with input optical laser pulse. A PIN photodetector with responsivity of 1 A/W and dark current of 10 nA is used to convert the optical pulses to array of radio frequency (RF). Here, transmission of SA via 70 km fiber optics and 25 m wireless has been investigated.

This article presents the techniques of determination of suitable material to control of light such as generating slow, fast pulse using nano ring resonator. Nano ring resonator (NRR) systems made of different materials. Nano ring device can be constructed with radius in the size of a nano meter. The concepts behind optical ring resonators are the same as those behind whispering galleries except that they use light and obey the properties behind constructive interference and total internal reflection. In this research, ring resonators are made of InGaAsP/InP, GaAlAs/GaAs and hydrogenated amorphous silicon (a-Si:H) materials.

The radio frequency (RF) signal generation and its modulation is the basic building block of wireless communication system. High frequency RF signals are desired in high speed systems but traditional methods to generate high frequency RF signals suffered from electronic devices data processing rate. On the other hand, spectral efficient modulation is also played vital rule in the high speed wireless communication where orthogonal frequency-division multiplexing (OFDM) transmission is mostly preferred. Due to the challenges regarding to electronic devices, optically generation and processing of RF OFDM signals has gained considerable attention. In this work microring resonator (MRR) system is used to implement all optically generation and modulation of RF OFDM signal. The MRRs can be used as filter devices where generation of high frequency (GHz) soliton signals as single and multi-carrier can be performed using suitable system parameters. The results show the generation of 64 multi-carriers evenly spaced in the range from 54.09 GHz to 55.01 GHz to generate OFDM signal all optically, where the RF modulation was achieved by two optical carriers with free spectral range (FSR) = by 5 GHz.

System of optical soliton amplification which consists of an add/drop multiplexer system is presented. Optical dark and bright soliton pulses can be amplified significantly. Dark soliton and Gaussian laser beam are input into the configured system and travel within the waveguide. Continuous soliton pulse will be sliced into smaller pulses by the nonlinear effect known as chaos, thus large bandwidth of optical signals can be obtained. Amplification occurs when the soliton propagates along the add/drop multiplexer system. Amplified optical tweezers signals with power of 487 W and FWHM of 6.8 nm are simulated. The amplified bright soliton could be obtained with maximum power of 360 W and FWHM of 1.5 nm. Therefore amplification of soliton pulses can be used to perform the long distance optical communication.

The flow of muck and cuttings in the face, cutterhead, cutting chamber, and screw conveyor determines the pressure profile of the excavated soil as well as its impact on the wear of the related components in a soft ground tunneling machine. This paper discusses the use of Computational Fluid Dynamic (CFD) to simulate the flow characteristic of the conditioned soil in the screw conveyor of Earth Pressure Balance (EPB) tunnel boring machine. In this simulation, conditioned soil assumed to behavior as a Bingham plastic fluid. Back analysis method in conjunction with CFD modeling is used to calculate the rheological properties of soil from a set of known screw conveyor torque read outs from a machine operating in Seattle, WA. The error of the torque values between the simulation results and actual field data is in the range of 0.1–6.2%. This illustrate that the CFD method can simulate the soil movement in the screw conveyor of EPB machines. The results also indicates that the same approach can be used to optimize the machine design to minimize torque and wear as well as optimizing machine operating parameters during the tunneling operation to improve productivity and have a better control of the face pressure.

We have shown that an add/drop system connected to a single microring resonator could be constructed using the fiber optics, where it can be used to generate a single soliton carrier, in which the tuning and manipulation of the bandwidth is performed to control the output signals. The chaos filtering via the add/drop device is implemented by using suitable parameters of the system. The coupling coefficient of the system is considered to be an effective parameter to determine the output intensity power of the system. In order to optimize the system, the smaller coupling coefficient is required. The bandwidth of the generated pulse changes respects to variation of the coupling coefficient. Here the chaotic signals which are used widely in communication, for variation of coupling coefficients is analyzed. To recover the pulses from the chaotic noises in the fiber ring resonator, we use the add/drop filter system with the appropriate parameters, where the insertion loss and gain of the system is measured. As a result, the increase of the coupling coefficients leads to increase of the bandwidth of the soliton pulse. In order to use ultra-short soliton pulses applied in optical communication, lower coupling coefficient is admired where, the power control can be performed within the system.

The interferometer system of microring resonator (MRR) can be used to generate soliton tweezers applied for medical applications. This system uses the nonlinear behaviors of light pulse traveling within a fiber optics MRR. The soliton tweezers can be used to contact the biological cells of a human tissue. Here, the non-heat creating laser is required to perform the cold laser (CL) therapy which can be utilized by a generation of low power soliton tweezers using the MRRs. The NIR (near infra-red) laser is used to generate soliton tweezers which are able to penetrate profoundly into tissues in order to improve injury healing and tissue regeneration. The Dark solitons and Gaussian beam with central wavelength of 800 nm collide within the MRR system lead to generate ultra-short soliton tweezers. This type of treatment is effective and based on the photochemical and photobiological effects of the cells and tissues or any biological response by means of power transfer. Thus, the CL using the soliton tweezers provides energy toward the entire body in the form of non-thermal photons of light. In this research soliton tweezers with full width at half maximum (FWHM) of 1.5, 4, 6.8 and 15 nm are generated and used to interact with the living cells and human tissues.

An optical add-drop filter system is used to generate ultra-short nanometer (nm) bandwidth soliton pulses to be transmitted along the nano communication nonlinear fiber optics. In order to reduce the loss during the transmission, ultra-short soliton pulses are recommended. The theoretical part of this study uses the Z-transform method to present the characteristic transmission of the optical add-drop filter system. The nonlinear refractive index of the fiber optic transmission link is 2.6×10-20 m2/W. The Wavelength Division Multiplexing (WDM) can be performed to enhance the capacity of the system. This occurs when the bigger size of the ring resonator is used. Here, soliton pulses with bandwidths of 2.1 and 0.42 nm are generated and transmitted over the fiber optic length, where signals with a bandwidth of 55 and 200 ps are successfully detected at the end of the transmission link.

The add-drop ring resonator system is the fundamental building block of optical transmission and communication systems. An add-drop microring resonator (MRR) consisting of a $$120\,\upmu \hbox {m}$$ diameter loop of optical waveguide was used to filter the input spectrum of a mode-locked laser. The experimental setup is used to generate soliton mode-locked laser pulse, where we used the experimental data to model and simulate the propagation of the mode-locked soliton laser pulse within the MRR. The transmission characteristics of the through and drop ports output signals from this system are described in this paper. As results, multi-wavelength mode lock soliton with full width at half maximum and free spectral range (FSR) of 8 pm and 0.67 nm were generated respectively. The FSR of the input signals are enlarged significantly by the system, thus separating signal wavelengths by a resonator has been investigated. In the proposed scheme, FSR-spaced signals are leveraged as a means of obtaining higher bandwidth output signals while using an add-drop MRR.

Femtosecond optical tweezers are an effective tool for handling individual human red blood cells, as they allow for comparatively easy single cell manipulation with consequent diverse applications in biological science. Optical trapping at low power with short exposure time is desired in order to minimize damage in the vicinity of targeted tissue, and such a requirement can be achieved by using micro-ring resonators in an optical tweezers configuration. This paper describes a modified add/drop multiplexer system, known as half-panda ring resonator, which is suitable for human blood cells trapping and deployment during investigations on deformation and vibration behavior of biological cells. Dark-bright solitons and Gaussian beams are propagated within the proposed system, while the output features can be controlled via manipulation of specific parameters. This study details optical tweezers of FWHM of 33 and 100, and 90 and 152 femtoseconds that are generated at the drop and through ports of the system respectively

This paper describes a demonstration of soliton transmission over fiber-wireless (Fi-Wi) networks using mode-locked stable solitons over a 50-km-long fiber and a short-distance wireless link. Ultrashort optical pulse sources in the 1.5- $\mu\hbox{m} $ region are seen as increasingly important for achieving ultrahigh-speed optical transmission and signal processing at optical nodes. Mode-locked solitons were generated by a simple ring laser cavity incorporating a very thin layer of carbon nanotube (CNT), together with an erbium-doped fiber (EDF) laser used as an active bulk gain medium. Experimental measurements involved the transmission of the generated mode-locked soliton over a 50-km-long single-mode fiber (SMF), and a radio-frequency (RF) spectrum subsequently generated was a result of beating frequency of wavelengths launched into the photodetector at the other end of the SMF. This RF spectrum array was in the range of WiFi frequencies. System performance was evaluated by first selecting one of the RF carriers centered at 2.5 GHz via an RF bandpass filter and subsequently using this carrier to transmit quadrature phase-shift keying (QPSK) and 16-quadrature amplitude modulation (16-QAM) data signals. The described optical circuit, containing an EDF laser, a CNT, an SMF, and a wireless link, was shown to achieve ultrastable transmission of mode-locked soliton over a long-distance Fi-Wi network.

This paper presents a multi-soliton generation system for terabit data transmission. In this system, multi-solitons are produced by a series of micro-ring resonators (MRRs) incorporated with an add/drop filter. The generated multi-solitons are equalized by wavelength selective switch, therefore achieving flat frequency combs that can be used as multi-wavelengths for data transmission. The output signals from the MRRs, which have a soliton pulse range of 191.2–195.7 THz, result in 345 comb multi-wavelengths with specific FSR of 12.5 GHz. After the comb spectrum is split into odd and even carriers, 16-QAM is used to modulate each carrier with sinc-shaped Nyquist pulses. At this point, the modulation of neighboring carriers generates spectrally overlapping channels, which emulate orthogonal frequency division multiplexing. By applying 345 carriers, 16-QAM modulation, polarization multiplexing, and exploiting sinc-shaped Nyquist pulses with symbol rates of 12.5 GBd, a total data rate of 34.5 Tbit/s is achievable. The error vector magnitude and bit error rate of the system are also discussed.

A system comprises of a W-band (75-110 GHz) optical millimeter (mm)-wave generation using microring resonators (MRRs) and radio-over-fiber (RoF) link architectures is presented for multigigabit data rates demand. The MRRs are used to generate optical mm-wave soliton pulses for W-band applications. To achieve faster transmission speed wirelessly, higher spectral efficiency (SE) and better transmission performance, orthogonal frequency-division multiplexing (OFDM) is used. The results show that the MRRs support W-band optical soliton pulses, which can be used in an OFDM transmission/receiver system. Localized narrow bandwidth soliton pulses within frequencies of 92.2-93.2 GHz can be seen in the throughput port of the Panda system with respect to the full width at half maximum and free spectrum range of 3.5 and 184 MHz, respectively. The error vector magnitude of the system was measured and the viability of the solitonic OFDM-based system for RoF link over 25-Km fiber link and 2-m wireless link was confirmed. The data rate of the system with 16-quadrature amplitude modulation is measured as 43.6 Gb/s and with 10 GHz of bandwidth, the SE is obtained as 4.36 bit/s/Hz.

Multi-carrier generation is the main building block for generating WiMax signal. In order to use WiMax signal in radio over fiber applications the use of all optical generation of RF signals is required. To generate multi carriers optically, the system consisting of series of microring resonators (MRRs) incorporating with an add/drop filter system are used. Thus the high frequency (THz) solitons range of 193.29–193.35 THz at frequencies of 193.333, 193.3355 and 193.3388 THz with the free spectral range of 2.5 and 5.8 GHz could be performed using MRRs, providing required WiMax signal used in wired/wireless communication. The generated multi carriers are multiplexed with the single carrier soliton and transmitted through single mode fiber (SMF) after being beaten to photodiode, a WiMax signal is propagated wirelessly in transmitter antenna base station and is received by the second antenna located in the receiver. Here, based on the switching of channel 1 or channel 2, the 2.5 or 5.8 GHz RF WiMax can be generated. When the RF signal is up-converted at the receiver central office, the detected signal is analysed in order to evaluate the error vector magnitude (EVM) of each wireless channel. As results, both channels show a soft EVM variation for different path lengths, where the transmission of both channels is feasible for up to a 50 km SMF path length.

Microring resonators (MRRs) can be used to generate optical millimetre-wave solitons with a broadband frequency of 40-60 GHz. Non-linear light behaviours within MRRs, such as chaotic signals, can be used to generate logic codes (digital codes). The soliton signals can be multiplexed and modulated with the logic codes using an orthogonal frequency division multiplexing (OFDM) technique to transmit the data via a network system. OFDM uses overlapping subcarriers without causing inter-carrier interference. It provides both a high data rate and symbol duration using frequency division multiplexing over multiple subcarriers within one channel. The results show that MRRs support both single-carrier and multi-carrier optical soliton pulses, which can be used in an OFDM based on whether fast Fourier transform or discrete wavelet transform transmission/receiver system. Localised ultra-short soliton pulses within frequencies of 50 and 52 GHz can be seen at the throughput port of the panda system with respect to full-width at half-maximum (FWHM) and free spectrum range of 5 MHz and 2 GHz, respectively. The soliton pulses with FWHMs of 10 MHz could be generated at the drop port. Therefore, transmission of data information can be performed via a communication network using soliton pulse carriers and an OFDM technique.

One of the main operational parameters in pressurized full face soft ground tunneling with machines such as earth pressure balance (EPB) TBMs is soil conditioning. Soil conditioners which are proper foam or conditioning agents, are often injected through the cutterhead or into the cutting chamber to make the muck flowable, lower inner friction between the soil particles, control soil stickiness, prepare the excavated soil to be compressible during the tunneling operation, control the water inflow, reduce the torque on the cutterhead, and lower power and torque of the screw conveyor. Foams can also be used in hard rock tunneling to reduce the wear and torque to replace conventional dust suppression by water sprays. This paper reviews the common practice in soil conditioning and focuses on assessing the influence of the conditioning on tool wear and torque requirement of the machines. Tests performed on many standard type soils and few samples from soft ground tunneling projects around the US on Penn State Soil Abrasion testing device. The results of tests performed in dry, moist and conditioned soil will be discussed and compared in this paper. The preliminary results show that the use of proper soil conditioning can reduce the wear of cutters and machine components by orders of magnitude while it can reduce the torque by over 50%.

A system involving W-band (75–110 GHz) optical millimeter (mm)-wave generation using the external optical modulator (EOM) in a radio-over-fiber (RoF) link is presented for satisfying the requirements for multi-gigabit-per-second data rates. A 90-GHz mm-wave signal was generated by a nonupling (nine times) increase in only a 10-GHz local oscillator by biasing the EOM at its zero level and choosing an appropriate modulation index. To achieve a fast transmission speed wirelessly, high spectral efficiency (SE), and better transmission performance, orthogonal frequency-division multiplexing (OFDM) is used. The bit error rate (BER) and error vector magnitude (EVM) of the system were measured for three different fiber lengths and for a wireless distance of 1–5 m. The results show that the system with the SE of $\sim$ 4 (b/s)/Hz and 16-ary quadrature amplitude modulation (QAM) 40-GB/s OFDM signals can be received by the end user with BER less than $3.8\times 10^{-3}$ and EVM less than 25% over a 50-km optical fiber and 3-m wireless link.

In this paper, an adaptive control system is employed in a novel implementation technique of the feed forward linearization system for optical analog communication systems' laser transmitter. The adaptive control system applies the Newton trust-region dogleg algorithm, which is a numerical optimization algorithm, to automatically tune the adjustment parameters in the feed forward loops to optimize the feed forward system performance and adapt to process variations. At the end of this paper, significant reductions of over 20 dBm in the third-order inter modulation distortion products have been achieved for operating frequencies from 5.0 to 5.8 GHz.

The optical carrier generation is the basic building block to implement all-optical orthogonal frequency-division multiplexing (OFDM) transmission. One method to optically generate single and multicarriers is to use the microring resonator (MRR). The MRRs can be used as filter devices, where generation of high-frequency (GHz) soliton signals as single and multicarriers can be performed using suitable system parameters. Here, the optical soliton in a nonlinear fiber MRR system is analyzed, using a modified add/drop system known as a Panda ring resonator connected to an add/drop system. In order to set up a transmission system, i.e., IEEE802.11a, first, 64 uniform optical carriers were generated and separated by a splitter and modulated; afterward, the spectra of the modulated optical subcarriers are overlapped, which results one optical OFDM channel band. The quadrature amplitude modulation (QAM) and 16-QAM are used for modulating the subcarriers. The generated OFDM signal is multiplexed with a single-carrier soliton and transmitted through the single-mode fiber (SMF). After photodetection, the radio frequency (RF) signal was propagated. On the receiver side, the RF signal was optically modulated and processed. The results show the generation of 64 multicarriers evenly spaced in the range from 54.09 to 55.01 GHz, where demodulation of these signals is performed, and the performance of the system is analyzed.