Crosstalk Reduction Research Articles

A Novel Optimization Method for Lenticular 3-D Display Based on Light Field Decomposion

Crosstalk is a primary defect in affecting the image quality of stereoscopic three-dimensional (3-D) displays. Until now, the crosstalk reduction methods either require extra devices or need tedious calibration procedures, which require precise measurement on each display device. We propose herein a new method of synthesizing lenticular 3-D display based on the light field decomposition and optimization to minimize the crosstalk. The light field concept is introduced into lenticular 3-D display. Rays of multiview light field are back-projected to the LCD plane to form a synthetic image, with subpixel resolution. A weighted value considering all arriving rays is assigned for the subpixel to reduce crosstalk. We developed a new algorithm of ray’s mergence and assignment for a smooth fusion of different views and crosstalk reduction. We also performed validation experiments which convincingly demonstrated that our new method is capable of reducing the crosstalk on synthetic graph. Compared with existing methods, our proposed new method is simple and effective, and implementation cost is low.

An expandable crosstalk reduction method for inline fiber Fabry–Pérot sensor array based on fiber Bragg gratings

The inline time division multiplexing (TDM) fiber Fabry–Pérot (FFP) sensor array based on fiber Bragg gratings (FBGs) is attractive for many applications. But the intrinsic multi-reflection (MR) induced crosstalk limits applications especially those needing high resolution. In this paper we proposed an expandable method for MR-induced crosstalk reduction. The method is based on complexing-exponent synthesis using the phase-generated carrier (PGC) scheme and the special common character of the impulse responses. The method could promote demodulation stability simultaneously with the reduction of MR-induced crosstalk. A polarization-maintaining 3-TDM experimental system with an FBG reflectivity of about 5 was set up to validate the method. The experimental results showed that crosstalk reduction of 13 dB and 15 dB was achieved for sensor 2 and sensor 3 respectively when a signal was applied to the first sensor and crosstalk reduction of 8 dB was achieved for sensor 3 when a signal was applied to sensor 2. The demodulation stability of the applied signal was promoted as well. The standard deviations of the amplitude distributions of the demodulated signals were reduced from 0.0046 to 0.0021 for sensor 2 and from 0.0114 to 0.0044 for sensor 3. Because of the convenience of the linear operation of the complexing-exponent and according to the common character of the impulse response we found, the method can be effectively extended to the array with more TDM channels if the impulse response of the inline FFP sensor array with more TDM channels is derived. It offers potential to develop a low-crosstalk inline FFP sensor array using the PGC interrogation technique with relatively high reflectivity FBGs which can guarantee enough light power received by the photo-detector.

Feasibility studies for a wireless 60 GHz tracking detector readout

The amount of data produced by highly granular silicon tracking detectors in high energy physics experiments poses a major challenge to readout systems. At high collision rates, e.g. at LHC experiments, only a small fraction of data can be read out with currently used technologies. To cope with the requirements of future or upgraded experiments new data transfer techniques are required which offer high data rates at low power and low material budget.Wireless technologies operating in the 60GHz band or at higher frequencies offer high data rates and are thus a promising upcoming alternative to conventional data transmission via electrical cables or optical fibers. Using wireless technology, the amount of cables and connectors in detectors can be significantly reduced. Tracking detectors profit most from a reduced material budget as fewer secondary particle interactions (multiple Coulomb scattering, energy loss, etc.) improve the tracking performance in general.We present feasibility studies regarding the integration of the wireless technology at 60GHz into a silicon tracking detector. We use spare silicon strip modules of the ATLAS experiment as test samples which are measured to be opaque in the 60GHz range. The reduction of cross talk between links and the attenuation of reflections is studied. An estimate of the maximum achievable link density is given. It is shown that wireless links can be placed as close as 2cm next to each other for a layer distance of 10cm by exploiting one or several of the following measures: highly directive antennas, absorbers like graphite foam, linear polarization and frequency channeling. Combining these measures, a data rate area density of up to 11Tb/(s·m2) seems feasible. In addition, two types of silicon sensors are tested under mm-wave irradiation in order to determine the influence of 60GHz data transmission on the detector performance: an ATLAS silicon strip sensor module and an HV-MAPS prototype for the Mu3e experiment. No deterioration of the performance of both prototypes is observed.

Characterization of a 6×6-mm2 75-μm cell MPPC suitable for the Cherenkov Telescope Array project

This paper presents the latest characterization results of a novel Low Cross-Talk (LCT) large-area (6×6-mm2) Multi-Pixel Photon Counter (MPPC) detector manufactured by Hamamatsu, belonging to the recent LCT5 family and achieving a fill-factor enhancement and cross-talk reduction. In addition, the newly adopted resin coating is demonstrated to yield improved photon detection capabilities in the 290–350nm spectral range, making the new LCT MPPC particularly suitable for emerging applications like Cherenkov Telescopes. For a 3×3-mm2 version of the new MPPC under test, a comparative analysis of the large pixel pitch (75-µm) detector versus the smaller pixel pitch (50-µm) detector is also undertaken. Furthermore, measurements of the 6×6-mm2 MPPC response versus the angle of incidence are provided for the characterized device.

Reduction of cross-talks between circuit and sensor layer in the Kyoto's X-ray astronomy SOI pixel sensors with Double-SOI wafer

We have been developing silicon-on-insulator pixel sensors, “XRPIXs,” for future X-ray astronomy satellites. XRPIXs are equipped with a function of “event-driven readout,” with which we can read out only hit pixels by trigger signals and hence realize good time resolution reaching ∼10μs. The current version of XRPIX suffers from a problem that the spectral performance degrades in the event-driven readout mode compared to the frame-readout mode, in which all the pixels are read out serially. Previous studies have clarified that one of the causes is capacitive coupling between the sense node and the trigger signal line in the circuit layer. In order to solve the problem, we adopt the Double SOI structure having a middle silicon layer between the circuit and the sensor layers. We expect the middle silicon layer to work as an electrostatic shield and reduces the capacitive coupling. In this paper, we report the spectroscopic performance of XRPIX with the middle silicon layer. We successfully reduce the capacitive coupling and the readout noise.

A Shielding Structure for Crosstalk Reduction in Silicon Interposer

High-density interconnects including redistribution layers (RDLs) and through-silicon-vias (TSVs) in silicon interposer require effective crosstalk-reduction signaling schemes. In this letter, a novel ground RDL lines structure utilizing ohmic contact is proposed for coupling mitigation, where the conventional insulator layer between the silicon substrate and the ground RDL lines is removed. An equivalent circuit model is developed to capture the coupling reduction mechanism. The proposed structure is then verified by the full-wave simulations. Finally, a test sample is fabricated and measured. The measurement results show a good correlation with those of the developed equivalent circuit model.

A Hybrid NRZ/Multi-Tone I/O With Crosstalk and ISI Reduction for Dense Interconnects

A low-power four-channel hybrid NRZ/multi-tone transceiver for multi-drop bus (MDB) memory interfaces is designed and fabricated in 40 nm CMOS technology. The proposed system achieves 1 pJ/bit power efficiency, while communicating over an MDB channel with 45 dB loss at 3 GHz. The multi-tone (MT) nature of the proposed transceiver helps to control the intersymbol interference (ISI) and reduce the far-end crosstalk (FEXT), which results in a very energy-efficient implementation. The core size area is ${{80\times60\; {\upmu}\text{m}^2}}$ and ${130\times60\; {\upmu}\text{m}^2}$ for the TX and RX blocks (including the clock unit), respectively.

Copper-Filled Through-Silicon Vias With Parylene-HT Liner

Organic low- $k$ materials have been considered in the literature for satisfying the requirements of lowering the dielectric constant of the dielectric layer to decrease the problem of signal delay, lower power consumption, and to reduce cross talk between the neighboring paths, and lowering the fabrication temperature budget. In this paper, the feasibility of using Parylene-HT as a low-temperature deposition, high-uniformity coverage low-dielectric liner for copper-filled through-silicon vias (TSVs) in 3-D integration is investigated. In particular, the capability of embedding Parylene-HT in via-last fabrication process is validated through the demonstration of 100- $\mu \text{m}$ -depth bottom-up copper-filled TSVs. TSVs with Parylene-HT as a liner were realized through vias etching, parylene vapor deposition, and copper electroplating processes. The Parylene-HT deposition and copper electroplating processes were implemented at room temperature, such that thermal-related issue would be avoided and device reliability would be enhanced. The insulation function of the Parylene-HT liner of the fabricated TSVs was characterized. Capacitance of 0.164 pF/TSV and leakage current density of 22 pA/cm2 at a field of 0.25 MV/cm were obtained through the measurement of the TSV arrays. The obtained results reveal the possibility of using such a high potential parylene in low-temperature budget 3-D integration applications.

Mode-Division-Multiplexing of Multiple Bessel-Gaussian Beams Carrying Orbital-Angular-Momentum for Obstruction-Tolerant Free-Space Optical and Millimetre-Wave Communication Links.

We experimentally investigate the potential of using ‘self-healing’ Bessel-Gaussian beams carrying orbital-angular-momentum to overcome limitations in obstructed free-space optical and 28-GHz millimetre-wave communication links. We multiplex and transmit two beams (l = +1 and +3) over 1.4 metres in both the optical and millimetre-wave domains. Each optical beam carried 50-Gbaud quadrature-phase-shift-keyed data, and each millimetre-wave beam carried 1-Gbaud 16-quadrature-amplitude-modulated data. In both types of links, opaque disks of different sizes are used to obstruct the beams at different transverse positions. We observe self-healing after the obstructions, and assess crosstalk and power penalty when data is transmitted. Moreover, we show that Bessel-Gaussian orbital-angular-momentum beams are more tolerant to obstructions than non-Bessel orbital-angular-momentum beams. For example, when obstructions that are 1 and 0.44 the size of the l = +1 beam, are placed at beam centre, optical and millimetre-wave Bessel-Gaussian beams show ~6 dB and ~8 dB reduction in crosstalk, respectively.

Nanoscale Silicon-on-Insulator Photo-Activated Modulator Building Block for Optical Communication

The constantly growing use of real-time computing generates constant urge for much faster processors than those which are currently available in the market. Correspondingly, there is an accelerated development of new optics communication related applications and components. The effort to combine those two trends leads to the generation of new optoelectronic nanodevices. Such hybrid devices may allow high operation speed, reduced cross talk and other noises, low operation power, and obviate the need for the existing electro-optical convertors. In this letter, we present the design, simulation, fabrication, and characterization of an optoelectronic device based on silicon which is capable of speeding up the processing capabilities. This novel device is called silicon-on-insulator photo-activated modulator. The nature of the data flow in this device is electronic, while the modulation control command is optic. Since the external voltage in the final configuration design of the device is constant and no RC (electrical average response time) related delay is generated, faster operation rates are anticipated. This novel device can serve as a building block toward the development of optical data processing while breaking through the way to all optic processors based on silicon chips that are fabricated via typical microelectronics fabrication process.

真直形状測定用 3 点法マルチカンチレバー変位計の高感度化モデルの検討

In this study, we developed a multi cantilever device for straightness measurement using the three point method. This device has three triangular cantilever works as displacement sensors. When the displacement is given at the probe placed at the end of the cantilever, stress arises in the cantilever. Displacement is measured by detecting the stress change using two piezo resistances at the root of the cantilever. This paper presents the results of sensitivity evaluation of improved device models. To improve the sensitivity, we considered the shape to make stress concentration in the strain detecting section of the device, and examined the effects by the finite element method. As a result, it was confirmed that transverse notches on both sides at the root of the cantilever and a rectangular hole between the piezo resisances are effective for sensitivity improvement and crosstalk reduction. Furthermore, we also simulate models of changing thickness of each part and models of changing position of piezo resistance.

Crosstalk Reduction on 6-line Suspension Assembly Interconnect Trace in Head Gimbal Assembly by using Guard Technique

The guard technique is proposed by adding the stainless steel at backing layer to reduce the crosstalk on 6 lines suspension assembly interconnect trace (SAIT). The Near-End and Far- End crosstalk coefficients (NEXT and FEXT) are used to analyze the crosstalk on the SAIT in the frequency of 0-20GHz. The finite integration technique (FIT) is used in the simulation based on CST microwave studio. The space between heat and read pairs is modified and guard addition at the space is also varied. From the results, it is found that the varying of space cannot reduce the crosstalk. However, the additional guard can reduce the crosstalk by monitoring the NEXT and FEXT. The lowest crosstalk is at 100% of the space with 100% of guard that can attenuate the noise around 4.7 and 3.2dB for NEXT and FEXT, respectively. The 80% of space with 80% of additional guard has the crosstalk less than or equal to the conventional SAIT. In addition, it can also decrease the dimension of SAIT about 11.87% of the conventional SAIT. Hence, this technique can reduce the crosstalk and can decrease the dimension of the SAIT which is useful for the robustness for future SAIT design.

Windowing and Groove Depth Variation Techniques for Crosstalk Reduction on Six-Line Suspension Assembly Interconnect Trace in Magnetic Recording Heads

Windowing and Groove Depth Variation Techniques for Crosstalk Reduction on Six-Line Suspension Assembly Interconnect Trace in Magnetic Recording Heads

In vivo estimation of optical properties of rat liver using single-reflectance fiber probe during ischemia and reperfusion

To quantify the changes in optical properties of in vivo rat liver tissue, we applied diffuse reflectance spectroscopy (DRS) system using single-reflectance fiber probe during ischemia and reperfusion evoked by hepatic portal occlusion (hepatic artery, portal vein and bile duct). Changes in the reduced scattering coefficient μ s′, the absorption coefficient μ a, the tissue oxygen saturation StO2, and the oxidation of heme aa3 in cytochrome c oxidase (CcO) OHaa3 of in vivo rat liver (n = 6) were evaluated. Heme aa3 in CcO were significantly reduced (P < 0.05) during ischemia, which indicates a sign of mitochondrial energy failure induced by oxygen insufficiency of liver tissue. We found that OHaa3 obtained from the proposed method was unchanged immediately after the onset of ischemia and started gradually decreasing at 2 min after the onset of ischemia. Difference in the time course between OHaa3 and the conventional ratio metric analysis with μ a(605)/μ a(620) reported in literature demonstrates that the proposed method is effective in reduction of optical cross talk between hemoglobin and heme aa3. Our results suggest that DRS technique is applicable and useful for assessing in vivo tissue viability and hemodynamics in liver intraoperatively.

유연한 디스플레이 소자의 보호막용 직접 패턴 형성이 가능한 POSS계 저유전 물질의 제조

The passivation layer, which is located between a pixel electrode and a data elec- trode, must provide sufficiently low parasitic capacitance and sufficient electrical insulation to reduce cross talk and signal distortion. The present demand for passivation materials for next-generation displays has created interest in substitutes with low dielectric constant, high transmittance, thermal stability, and patternability; these requirements cannot be met by the silicon nitride layer and silicon dioxide used currently. To meet these requirements, negative-tone patterning systems containing polyhedral oligomeric silsesquioxane (POSS) were developed by adopting two different approaches: use of POSS in the polymeric matrix and in the crosslinker. The polymeric matrix, poly(methacryl isobutyl POSS-r- hydroxy styrene), showed improved dielectric property and thermal stability. However, the POSS content was limited owing to poor solubility. A POSS crosslinker with epoxy func- tional groups was used along with phenol group containing polymeric matrices; poly(4- hydroxy styrene). It was possible to pattern the POSS crosslinker system by irradiating it with UV light and subjecting it to subsequent thermal treatment. With increasing POSS content, the crosslinked materials showed increased transparency, higher thermal stability, and lower dielectric constant. The system could also be patterned by irradiating it with UV through a patterned mask.

Crosstalk Reduction With Bidirectional Signal Assignment on Square Lattice Structure 16-Core Fiber Over WDM Transmission for Gradual Upgrade of SMF-Based Lines

C-band and L-band wavelength division multiplexing (WDM) transmission performance was improved by using bidirectional signal assignment (BSA) to reduce crosstalk (XT) in square lattice structure 16-core fiber. Transmission of 16 WDM channels with 256-Gb/s polarization multiplexed-16 quadrature amplitude modulation signals on a 50-GHz grid with a net spectral efficiency of 4 b/s/Hz over 55-km of 16-core fiber spans was achieved. Use of BSA to reduce XT extended the transmission distance to 880 km in both types of transmission. Furthermore, transmission was achieved over eight mixed spans consisting of 16-core fiber and conventional single-mode fiber (SMF), demonstrating the possibility of gradually upgrading standard SMF-based lines to multicore fiber-based lines. With BSA, six 16-core fiber spans can be acceptable if the Q penalty from XT is below 0.5 dB.

Reflective Crosstalk Cancellation in Self-Seeded WDM PON for Mobile Fronthaul/Backhaul

Due to its large capacity and low latency, wavelength-division-multiplexed passive optical network (WDM PON) using self-seeded reflective semiconductor optical amplifier (RSOA) is an attractive, low-cost solution for mobile fronthaul/backhaul. However, multiple reflections in self-seeding cavity lead to reflective crosstalk, degrading its transmission performance. In this paper, reflective crosstalk in self-seeded RSOA under different bias conditions is experimentally characterized by its pulse response, and then novel feedforward and feedback approaches are proposed to suppress the reflective crosstalk in self-seeded WDM PON. Experimental results using a simple delay and differentiation method show significant reduction in the reflective crosstalk for self-seeded RSOA. With the proposed feedforward crosstalk cancellation, 2.5-Gb/s mobile backhaul using self-seeded RSOA achieves 1.7-dB performance improvement after transmission over 20-km single-mode fiber. In addition, low-cost bandwidth-efficient mobile fronthaul for 24 20-MHz LTE signals is demonstrated using a self-seeded RSOA with only 1.5-GHz bandwidth. With adaptive feedback crosstalk cancellation, the error vector magnitude for the received LTE signal after 20-km standard single-mode fiber transmission in the C-band is improved by 20%.

Investigation of Raman-Assisted Crosstalk Reduction in Multi-Wavelength Fiber Optical Parametric Amplification

Suppression of four-wave mixing (FWM) crosstalk during multi-wavelength amplification in a Raman-assisted fiber optical parametric amplifier (FOPA) is investigated theoretically and experimentally. The principle of crosstalk reduction by using a backward Raman pump is revealed by analytical expressions and verified by simulations. The crosstalk reduction is attributed to the unique power evolution of the signals caused by the monotonically increasing parametric pump power in the Raman-assisted FOPA. We obtain more than 7-dB reduction in FWM crosstalk initiated from both degenerate-FWM and nondegenerate-FWM processes in the Raman-assisted FOPA, as compared to a conventional FOPA with equivalent signal gain. The experimental results show excellent agreement with the simulations. We also discuss the effects of signal channel number and the powers of the parametric pump and the Raman pump on the FWM crosstalk. The simulation results indicate that under the same level of signal gain, the amount of crosstalk reduction can be increased by using a stronger Raman pump associated with a weaker parametric pump.

3D Synthesis and Crosstalk Reduction for Lenticular Autostereoscopic Displays

Novel image processing methods are presented in this work for 3D synthesis of multiview images and crosstalk reduction to improve the perceived image quality of lenticular autostereoscopic displays. First, for optimizing the intensity of a screen subpixel mapped to a fraction view number, a weighting method is proposed to blend the intensities of the corresponding subpixels from the two neighboring integer view images by minimizing the mean square error. Experimental results show that, comparing with the conventional rounding method, the proposed weighting method can effectively reduce the ghosting artifacts and sharpen the object boundaries when viewing at optimal integer viewpoints. Second, the crosstalk among vertical neighboring subpixels is modeled as a shift-invariant low-pass filter, and a novel computational efficient inverse filtering method is proposed for crosstalk reduction by applying fast Fourier transform (FFT) on each column of subpixels in the multiview interlaced screen image. In addition, a novel filtering method is proposed for determining the maximum input dynamic range of screen subpixel intensities. Experimental results demonstrate that the ghost image from neighboring views can be substantially diminished by the proposed inverse filtering method.

Advances in Multi-Pixel Photon Counter technology: First characterization results

Due to the recent advances in silicon photomultiplier technology, new types of Silicon Photomultiplier (SiPM), also named Multi-Pixel Photon Counter (MPPC) detectors have become recently available, demonstrating superior performance in terms of their most important electrical and optical parameters. This paper presents the latest characterization results of the novel Low Cross-Talk (LCT) MPPC families from Hamamatsu, where a noticeable fill-factor enhancement and cross-talk reduction is achieved. In addition, the newly adopted resin coating has been proven to yield improved photon detection capabilities in the 280–320nm spectral range, making the new LCT MPPCs particularly suitable for emerging applications like Cherenkov Telescope Array, and Astroparticle Physics.