Analog Signal Transmission Research Articles

Performance evaluation of analog signal transmission in an integrated optical vortex emitter to 36-km few-mode fiber system

We experimentally demonstrate and evaluate the performance of an analog signal transmission system with photonic integrated optical vortex emitter and 3.6-km few-mode fiber (FMF) link using orbital angular momentum (OAM) modes. The fabricated photonic integrated device is capable of emitting vector optical vortices carrying well-defined and quantized OAM modes with topological charge l=-2 and 2. After propagating through 3.6-km FMF, we measure and assess the spurious free dynamic range of the second-order harmonic distortion. Moreover, we study the impact of nonlinearity-induced resonance wavelength shift of the optical vortex emitter on the analog link performance as increasing the input optical power.

Minimization of service disturbance: VSM based case study in telecommunication industry

Significant investments in productivity improvement approaches over the past two decades have been embedded in ‘lean’ principles and philosophies within the manufacturing sector. Although the manufacturing sector has focused on offering integrated bundles of physical goods and services via product-service systems with lean principles and philosophies, there has been considerably less adoption of lean methodologies in the service sector. Hence, it is vital to investigate the application potential of lean principles in service processes’ productivity improvement. This manus cript presents the results of a case study performed to improve the service performance of a firm providing plain old telephone services (POTS). The firm provides, among other things, telecommunication related ‘voice-grade telephone services’ employing analog signal transmission over copper loops. The analysis methodology contains tailor-made value stream mapping (VSM) and value stream analysis (VSA), which has been carried out to investigate the current state of the value adding [also including non-value adding (not essential) and non-value adding (essential)] activities involved in the POTS related tasks. A current state value stream map (CSVS-Map) has been developed and VSA has been performed. Based on the CSVS-Map and the results of VSA, a future state value stream map (FSVS-Map) has been developed. Finally, the resulting improved performance of the POTS related tasks has been presented. The goal of this paper was to identify the advantages of implementing lean tools in service processes in the example of the described case study. The main obtained advantages are a 50% decrease in service lead time, which gives the capability to deliver almost double the amount of POTS installation service.

Optical radio-photonic channel for transmission of a coherent narrowband analog signal

The channel of an optical transmission line of coherent narrowband analog signal consisting of a continuous-wave laser, an electro-optic modulator, and a vector phase rotator based on electrically controlled fiber-optical 1 × 2 splitter and fixed delay lines is analyzed. The scheme is constructed from commercially available components used in digital optical communication systems. The applicability of components for analog and small-signal circuits is determined. Variation of radio signal phase in the range from 0° to 170° for radio signal frequencies between 1 and 2 GHz is demonstrated experimentally. It is shown that phase variation is a linear function of frequency in this range.

Baseband unit cloud interconnection enabled by flexible grid optical networks with software defined elasticity

The evolution toward 5G mobile networks is characterized by supporting higher data rate, excellent end-to-end performance and ubiquitous user-coverage with lower latency, power consumption, and cost. To support this, the RANs are evolving in two important aspects. One aspect is “cloudification,” which is to pool baseband units to be centralized for statistical multiplexing gain. The other aspect is to use advanced optical technologies for digital and analog signal transmission in a cloud-based RAN. In this article, we focus on BBU cloud interconnection with optical layer technologies. Flexible grid optical networks with the enabling technologies are introduced to provide elastic, transparent, and virtualized optical paths between the BBU pools. To improve the elasticity and intelligence of C-RAN, we propose a software defined centralized control plane to coordinate heterogeneous resources from three domains: the BBU domain, radio domain, and optical domain. We report an experimental demonstration of elastic lightpath provision for cloud radio-over-flexible grid optical networks in a software-defined-networking-based testbed.

Experimental demonstration of analog signal transmission in a silicon photonic crystal L3 resonator.

We design and fabricate a silicon photonic crystal L3 resonator for chip-scale analog signal transmission. The lattice constant (a) is 420 nm, and the radius of holes (r) is 126 nm. The three holes adjacent to the cavity are laterally shifted by 0.175a, 0.025a and 0.175a, respectively. We experimentally evaluate the performance of silicon photonic crystal L3 resonator for chip-scale analog signal transmission. The spurious free dynamic ranges (SFDRs) of the second-order harmonic distortion (SHD) and the third-order harmonic distortion (THD), which are important factors to assess the analog link performance, are measured for the chip-scale analog signal transmission through the fabricated silicon photonic crystal L3 resonator. The SHD SFDR and THD SFDR are measured to be ~34.6 dB and ~52.2 dB even with the input optical carrier sitting at the dip resonance wavelength of the fabricated silicon photonic crystal L3 resonator. The influences of the optical carrier wavelength and input optical power on the SHD SFDR and THD SFDR are studied in the experiment. The impacts of geometric parameters of the cavity structure (lattice constant, radius of holes, shift of the hole) on the analog signal transmission are also analyzed, showing favorable analog link performance with relatively large fabrication tolerance to design parameters.

Experimental performance evaluation of analog signal transmission in a silicon microring resonator.

We experimentally evaluate the performance of analog signal transmission in a silicon microring resonator. The spurious free dynamic range (SFDR) of the second-order harmonic distortion (SHD) and third-order harmonic distortion (THD) is used to assess the analog link. The performance dependence on the input signal wavelength and input signal power is comprehensively studied. The obtained results indicate that the analog signal transmission performance through microring resonator is mainly affected by the notch filtering effect for low-level input signal power. Moreover, with the increase of input signal power, the enhanced nonlinear resonance in the microring resonator could cause the shift of the resonance wavelength, which might also impact on the analog signal transmission performance.

Performance evaluation of analog signal transmission in an orbital angular momentum multiplexing system.

We propose and experimentally demonstrate analog signal transmission in an orbital angular momentum (OAM) multiplexing system. By employing two spatial light modulators (SLMs), each loaded with a complex phase pattern generating 4OAM beams, an 8OAM multiplexing system is established for analog signal transmissions. The crosstalk between each OAM channel is measured to assess the performance of the OAM multiplexing system. Using 3-GHz analog signals over 8OAM beams, we evaluate the performance of OAM multiplexing analog signal transmissions. The spurious free dynamic range (SFDR) of the second-order-harmonic distortion (SHD) and the third-order-harmonic distortion (THD) are measured and characterized for each OAM channel.

Secure chaotic transmission of electrocardiography signals with acousto-optic modulation under profiled beam propagation.

Electrocardiography (ECG) signals are used for both medical purposes and identifying individuals. It is often necessary to encrypt this highly sensitive information before it is transmitted over any channel. A closed-loop acousto-optic hybrid device acting as a chaotic modulator is applied to ECG signals to achieve this encryption. Recently improved modeling of this approach using profiled optical beams has shown it to be very sensitive to key parameters that characterize the encryption and decryption process, exhibiting its potential for secure transmission of analog and digital signals. Here the encryption and decryption is demonstrated for ECG signals, both analog and digital versions, illustrating strong encryption without significant distortion. Performance analysis pertinent to both analog and digital transmission of the ECG waveform is also carried out using output signal-to-noise, signal-to-distortion, and bit-error-rate measures relative to the key parameters and presence of channel noise in the system.

Analog SC-FDE using SSB technique

In order to improve performance while keeping high spectrum efficiency of analog signal transmission, we recently proposed an analog single-carrier transmission with frequency-domain equalization (analog SC-FDE). In this paper, in order to improve the spectrum efficiency, analog SC-FDE using single sideband (SSB) technique is proposed. A theoretical analysis of normalized mean square error (NMSE) performance is carried out and confirmed by computer simulation. We show that analog SC-FDE using SSB technique achieves better NMSE performance than both conventional SSB transmission and analog SC-FDE while doubling spectrum efficiency of analog SC-FDE.

Improved performance of analog and digital acousto-optic modulation with feedback under profiled beam propagation for secure communication using chaos

Using intensity feedback, the closed-loop behavior of an acousto-optic hybrid device under profiled beam propagation has been recently shown to exhibit wider chaotic bands potentially leading to an increase in both the dynamic range and sensitivity to key parameters that characterize the encryption. In this work, a detailed examination is carried out vis-a-vis the robustness of the encryption/decryption process relative to parameter mismatch for both analog and pulse code modulation signals, and bit error rate (BER) curves are used to examine the impact of additive white noise. The simulations with profiled input beams are shown to produce a stronger encryption key (i.e., much lower parametric tolerance thresholds) relative to simulations with uniform plane wave input beams. In each case, it is shown that the tolerance for key parameters drops by factors ranging from 10 to 20 times below those for uniform plane wave propagation. Results are shown to be at consistently lower tolerances for secure transmission of analog and digital signals using parameter tolerance measures, as well as BER performance measures for digital signals. These results hold out the promise for considerably greater information transmission security for such a system.

A self-adaptive method for creating high efficiency communication channels through random scattering media.

Controlling the propagation of electromagnetic waves is important to a broad range of applications. Recent advances in controlling wave propagation in random scattering media have enabled optical focusing and imaging inside random scattering media. In this work, we propose and demonstrate a new method to deliver optical power more efficiently through scattering media. Drastically different from the random matrix characterization approach, our method can rapidly establish high efficiency communication channels using just a few measurements, regardless of the number of optical modes, and provides a practical and robust solution to boost the signal levels in optical or short wave communications. We experimentally demonstrated analog and digital signal transmission through highly scattering media with greatly improved performance. Besides scattering, our method can also reduce the loss of signal due to absorption. Experimentally, we observed that our method forced light to go around absorbers, leading to even higher signal improvement than in the case of purely scattering media. Interestingly, the resulting signal improvement is highly directional, which provides a new means against eavesdropping.

Analog electro-optical readout of SiPMs for compact, low power ToF PET/MRI.

The aim of this work is to demonstrate time of flight (ToF) performance from analog electro-optical transmission of SiPM-based PET detector signals. In electro-optical readout schemes, scintillation signals are converted to near-infrared light by a laser diode and transmitted out of the MRI bore with fiber-optics [1], greatly reducing the PET system's footprint, power consumption, and mutual interference with the MRI. Our approach uses vertical-cavity surface-emitting lasers (VCSEL) and _ber-optics borrowed from telecommunication systems to directly transmit analog signals from an SiPM (see Figure ​Figure1).1). Our experiments used 3mm x 3mm x 5 mm teflon wrapped, and 3mm x 3mm x 20mm ESR wrapped LYSO scintillation crystals, 3mm x 3mm C30742- 33-50-C SiPMs (Excelitas, Waltham, USA), ZX60-4016E+ preamplifiers (Minicircuits, Brooklyn, USA), HFE4192-58X VCSELs (Finisar, Sunnyvale,USA), and 10m multi- mode optical patch cables. The VCSEL was characterized as seen in Figure ​Figure2.2. To get the best analog performance a bias current just above the laser threshold (1.7 mA) was chosen to minimize noise, and power dissipation (2.8 mW). Figure 1 Simplified schematics for the three data acquisition modes used in our experiments. In electrical mode an amplified SiPM signal was sent directly to a high speed oscilloscope for timing pickoff. In electro-optical modes 10% of the analog SiPM signal ... Figure 2 Characterization of the HFE4192-58X VCSEL. Its current rises exponentially with voltage (left). After the laser threshold current is surpassed, it's optical power (middle) and output noise levels (right) rise linearly with current. To optimize SNR a ... The results of the timing experiments are seen in Figure ​Figure3.3. The best timing resolution achieved with 5mm length crystals was 147ps +/- 1ps in electrical mode, 148ps +/- 2ps in electro-optical with preamp mode, and 182 +/- 2ps in electro-optical without preamp mode. With 20mm length crystals the best timing achieved was 220 +/- 3ps in electrical mode, 230 +/- 2ps in electro-optical with preamp mode, and 230 +/- 2ps in electro-optical without preamp mode. Figure 3 Fwhm timing resolutions for each readout mode with 5mm length and 20mm length LYSO crystals at threshold levels normalized to the amplitude of a single photo-electron pulse for each readout mode. The electro-optical readout degraded timing, but still ... This work shows that SiPM ToF information can be preserved after analog electro- optical transmission. In the future this readout strategy could drastically simplify the design of high performance PET/MRI systems by reducing the in-bore electronics to two active components (SiPMs and VCSELs).

Enabling In-Band Bidirectional OFDM-Uplink and OOK-Downlink Transmission in Long-Reach RSOA-Based WDM-PON Systems

We present a simple, straightforward technique to enable bidirectional transmission of analog and digital signals in single-fiber wavelength division multiplexing passive optical network systems employing reflective semiconductor optical amplifiers (RSOA). An On-Off-Keying (OOK-DL) downlink modulation is effectively erased in a saturated RSOA, reflecting a carrier for retransmitting on the same fiber an in-band analog WiFi orthogonal frequency division multiplexing uplink signal (OFDM-UL). We investigate the operating conditions and the optimization procedure to attain required signal quality for both the uplink and downlink. We demonstrate experimentally the maximum distance and the best attainable performances for different lengths of standard single mode fiber (transmission). Bit error rate below the forward error correction threshold is obtained for WiFi OFDM-UL signal over 40 km and up to 80 km of SSMF using 64QAM and QPSK modulation modes, respectively. In all cases, we achieve error-free operation for the OOK-DL signal at 1 Gb/s.

Accurate interchannel pitch control in graded-index circular-core polymer parallel optical waveguide using the Mosquito method

We successfully fabricate polymer optical waveguides with graded-index (GI) circular cores whose diameter and interchannel pitch are accurately controlled using the Mosquito method: GI-core waveguides with 250-, 125- and 62.5-μm pitches are successfully obtained. The Mosquito method utilizing a microdispenser is a very simple technique for fabricating GI-circular-core polymer optical waveguides. The accurately controlled pitch is confirmed by a high connectivity with a commercially available multimode fiber (MMF) ribbon with a 125-μm pitch. Furthermore, by inserting the waveguide between two 12-channel MMF ribbons, we experimentally demonstrate 11.3 Gbps × 12 Ch. parallel signal transmission through a GI-core waveguide with a 125-μm pitch for the first time to the best of our knowledge.

Analog Single-Carrier Transmission with Frequency-Domain Equalization

In this paper, a new analog signal transmission technique called analog single-carrier transmission with frequency-domain equalization (analog SC-FDE) is proposed. Analog SC-FDE applies discrete Fourier transform (DFT), frequency-domain spectrum shaping and mapping, inverse DFT (IDFT), and cyclic prefix (CP) insertion before transmission. At the receiver, one-tap FDE is applied to take advantage of frequency diversity. This paper considers, as an example, analog voice transmission. A theoretical analysis of the normalized mean square error (NMSE) performance is carried out to evaluate the transmission property of the proposed analog SC-FDE and is confirmed by computer simulation. We show that analog SC-FDE achieves better NMSE performance than conventional analog signal transmission scheme.

Design of Digital K-Type Thermocouple Temperature Transmitter

The paper introduces a method of digital K-type thermocouple temperature transmitter design, which uses MAX6675, a digital K-type thermocouple converter, MCU and TTL/485 conversion circuit. MCU calculates thermoelectric potential of thermocouple by the result of MAX6675 firstly, and then obtains the temperature by reference tables of K-type thermocouple and linear interpolation method, and result is serial output in digital mode. The method can eliminate interference of analog signal transmission, and improve measurement accuracy.

Design and Application of Measure and Control System Based on CAN-Bus for Large Pumping Station Auxiliary Equipments

This paper is focused on the measure and control system for large pumping station auxiliary equipments. The design of system has advantages as follows, functions of sensing measure, compensation calculation and policy control are decentralized to the intelligent measure and control equipments in the field improve stability and reliability of the system; digitalized application eliminates the analog signal transmission errors and fundamentally improves the accuracy of measure and control; CAN-Bus has a higher data transfer rate and distribution capacity of bus resources; isolated CAN-Bus design makes the system anti-overvoltage ability strong; simple requirements of communication network wiring highlight the economy of the system. The application of the system is also described in the paper.

Cloud Computing Application in Building Monitoring System

Popularization of the building monitoring system requires huge data storage, information management and computing services. However, the analog signal transmission cannot meet the requirements anymore, therefore cloud computing has to play its role. For this purpose, this article brings up an overall design idea and physical deployment of a cloud-based building monitoring system.

Analog Signal Transmission in a High-Contrast-Gratings-Based Hollow-Core-Waveguide

In this paper, the performance of an on-chip hollow-core-waveguide (HW) using high-contrast gratings (HCG) for analog signal transmission is analyzed numerically. Simulation results indicate that after propagating 100 m in a HCG-HW with optimally designed parameters, there is very little degradation of either third-order intermodulation distortion spur-free dynamic range (IM3 SFDR) or third-order harmonic distortion (THD) SFDR. Due to the chromatic dispersion of the HCG-HW, the highest second-order harmonic distortion (SHD) SFDR is limited to 107.3 dB · Hz1 / 2. In addition, >; 100 dB · Hz 2/3 IM3 SFDR can be achieved over a radio frequency (RF) range of 80 GHz and an optical wavelength bandwidth of 50 nm after propagation 100 m through a HCG-HW. The parameter dependence of the waveguide performance is also investigated. With a ± 20 nm variation on all parameters, the propagation length in an HCG-HW is limited to ~ 6 m in order to maintain an IM3 SFDR of >; 100 dB · Hz 2 / 3.

An Analytical Model for Inductively Coupled Multichannel Implantable System With Micro-Coil Array

Implantable system is widely used for functional electrical stimulation to repair the damaged nerve function. We propose a multichannel wireless implantable system using micro-coil array to implement parallel signal transmission based on inductive coupling, which meets the increasing requirement of some implantable system for high data rate and high power efficiency. However, the magnetic coupling among carrier from different channels will affect the operation of each link. In this paper, this interference is analyzed and design equations are derived, which are used to design coils, arrange their position and apply carrier for each channel to maximize the data signal level received at the implant side. A prototype of multichannel system has been built and experimental results show that data can be transmitted parallelly and high data rate can be achieved. This theoretical calculation verifies the feasibility of using the micro-coil array to achieve multichannel transcutaneous transmission for neural electrical stimulation.