Transmission Crosstalk Research Articles

All-in-one multifunctional and deformation-insensitive carbon nanotube nerve patches enabling on-demand interactions

Artificial intelligence of things (AIoT) aims to establish smart informative interactions between humans and devices. However, common pixelated sensing arrays in AIoT applications present problems, such as hard and brittle devices, intricate wiring, complex structures, signal transmission crosstalk, and low precision. Herein, we show an innovative solution called all-in-one intelligent semitransparent interactive nerve patch (AISI nerve patch), which is realized by an electrical double-layer parallel separation structure with homogeneous soft conductive materials. Multifunctionality of sensing, recognition, and transmission is integrated into the AISI nerve patch, while its total thickness can be limited to the microscale level. The AISI nerve patch possesses favorable semitransparency (transmittance of ∼80%), which enables the interactive area not only to be accurately identified but also not to affect aesthetics. High flexibility and bending-insensitivity allow the AISI nerve patch to attach to any curved surface, making things intelligent and interactive without sacrificing interactive efficiency and stability. A rapid response time and unpixellated recognition result in the AIS interactive patch realizing near-undull and ultrahigh-precision interactive recognition. Spatiotemporally dynamic functionality enables perfect integration of the AISI nerve patch and artificial intelligence with a sensational recognition accuracy of over 99% for further development of AIoT.

Topologically protecting squeezed light on a photonic chip

Squeezed light is a critical resource in quantum sensing and information processing. Due to the inherently weak optical nonlinearity and limited interaction volume, considerable pump power is typically needed to obtain efficient interactions to generate squeezed light in bulk crystals. Integrated photonics offers an elegant way to increase the nonlinearity by confining light strictly inside the waveguide. For the construction of large-scale quantum systems performing many-photon operations, it is essential to integrate various functional modules on a chip. However, fabrication imperfections and transmission cross talk may add unwanted diffraction and coupling to other photonic elements, reducing the quality of squeezing. Here, by introducing the topological phase, we experimentally demonstrate the topologically protected nonlinear process of four-wave mixing, enabling the generation of squeezed light on a silica chip. We measure the cross-correlations at different evolution distances for various topological sites and verify the nonclassical features with high fidelity. The squeezing parameters are measured to certify the protection of cavity-free, strongly squeezed states. The demonstration of topological protection for squeezed light on a chip brings new opportunities for quantum integrated photonics, opening novel approaches for the design of advanced multi-photon circuits.

Differential Transmission Crosstalk

Differential Transmission Crosstalk

Design and Analysis of Beam Steering Multicore Fiber Optical Switches

The design and performance characteristics of a beam steering optical switch for multicore fibers (MCFs) are reported. Port count, core count, transmission crosstalk, or a combination thereof can be optimized for the required application. Decreasing port separation or increasing the maximum steering angle both increase port count, whilst a higher core count or larger mode field diameter increase port capacity or port count, respectively, at the expense of greater intercore crosstalk. Potential losses from system misalignments and fiber fabrication variations in the core pitch are also estimated. A 50 port switch is possible for a 25 $\mu$ m core pitch 7 core hexagonal trench assisted MCF (TA-MCF) with a total mean statistical crosstalk on the central core of $-$ 25 dB after 1 km, assuming an operational wavelength of 1550 nm and maximum collimator actuator angle of 10 $^{\circ }$ . In contrast, a high capacity 25 $\mu$ m core pitch 61 core hexagonal TA-MCF can still offer up to a 5 port switch for the same level of crosstalk. For longer link distances, $-$ 25 dB crosstalk after 100 km (metro network) is achievable for a 50 port switch using a 35 $\mu$ m core pitch 7 core TA-MCF. Similar levels of crosstalk can be accomplished at 1000 km (core network) for a 41 port switch using a 25 $\mu$ m core pitch 7 core TA-MCF.

Crosstalk-aware routing, spectrum, and core assignment in space-division multiplexing optical networks with multicore fibers

The transmission capacity of existing optical fiber will reach its physical limitation due to increasing network bandwidth. Recently, space-division multiplexing (SDM) technology has been proposed to increase the fiber transmission capacity. Multicore fiber (MCF) is a strong candidate for SDM transmission, but the intercore crosstalk will be a critical issue with MCF transmission. We make a specific analysis of transmission crosstalk in elastic optical networks. Then, the concept of spare spectrum availability is introduced to accommodate connection requests. Based on it, two different crosstalk-aware routing, spectrum, and core assignment algorithms are presented at different network states. Simulation results show that our proposed scheme improves the spectrum resource utilization and reduces blocking, with a cost of additional algorithm complexity and set-up delay.

A Study on Suppressing Crosstalk Through a Thick SOI Substrate and Deep Trench Isolation

Measurement and simulation studies are conducted on transmission crosstalk in thick silicon-on-insulator substrates. This paper focuses on the role of buried oxide layers and deep trench isolation in suppressing crosstalk. With radio frequency coupling paths on substrates depending on noise frequency, a deep trench guides noise signals to substrates and suppresses transmission crosstalk between input and output ports. Good agreement is obtained between electromagnetic field (EM) simulation and measurement results. The EM simulation results suggest different approaches might be used in designing deep trench isolation patterns for a middle resistivity (MR) substrate and a high resistivity (HR) substrate. Deep trench isolation plays a more important role in HR substrates than in MR substrates.

Wirebond crosstalk and cavity modes in large chip mounts for superconductingqubits

We analyze the performance of a microwave chip mount that uses wirebonds toconnect the chip and mount grounds. A simple impedance ladder model predictsthat transmission crosstalk between two feedlines falls off exponentially withdistance at low frequencies, but rises to near unity above a resonance frequency setby the chip to ground capacitance. Using SPICE simulations and experimentalmeasurements of a scale model, the basic predictions of the ladder model wereverified. In particular, by decreasing the capacitance between the chip and boxgrounds, the resonance frequency increased and transmission decreased. Thismodel then influenced the design of a new mount that improved the isolation to − 65 dB at 6 GHz, even though the chip dimensions were increased to1 cm × 1 cm, three times as large as our previous devices. We measured a coplanar resonator in thismount as preparation for larger qubit chips, and were able to identify cavity, slotline, andresonator modes.

Substrate crosstalk suppression capability of silicon-on-insulator substrates with buried ground planes (GPSOI)

Experimental s/sub 21/ transmission crosstalk studies have been conducted on silicon-on-insulator substrates with buried ground planes (GPSOI's) where a 2 /spl Omega/ per square metal-silicide buried ground plane existed between a 15 /spl Omega/-cm p-type silicon substrate and a 1 μm thick buried CVD oxide layer. Locally grounded transmission test structures fabricated on GPSOI were found to exhibit 20 dB increased crosstalk suppression compared to published data for high resistivity (200 /spl Omega/-cm) SOI substrates incorporating capacitive guard rings over a frequency range from 500 MHz to 50 GHz. This represents an order of magnitude improvement in crosstalk power suppression capability compared to existing state-of-the-art suppression techniques in silicon substrates.

Multiplexing and transmission of RF signals using an optical fiber

Ultrasonic non-destructive testing systems designed to control huge structures normally use several transducers in the reception stage. To avoid increasing the cost of electronics, a multiplexer is used to send all received signals to the same processing module. Traditionally, transmission of such signals is carried out using copper cables. For special applications (i.e. continuous monitoring of nuclear plants) metallic cables are not suitable because of their high sensitivity to electromagnetic perturbations. Moreover, the multiplexing is made electronically. When the distance between the transducers and the reception unit is large and/or electromagnetic noise is important, signal degradation takes place. The proposed system implements the transmission and multiplexing of ultrasonic electrical signals obtained by means of broadband transducers (up to 1 MHz), using an optical fiber. Optical fibers are made of dielectric materials (silica or plastic) so they are inherently passive to electromagnetic noise. Wavelength division multiplexing is utilized for adding channels to the system by means of fiber optic couplers and different light sources. The wavelengths of the optical signals utilized are located far apart in the optical spectrum in order to avoid serious crosstalk in transmission. The limit to the number of multiplexed channels depends on the optical fiber selected, the spectrum of the light sources and the wavelength division multiplexers or couplers utilized.

Demonstration of in-service supervisory repeaterless bidirectional wavelength-division-multiplexing transmission system

An in-service supervisory repeaterless bidirectional wavelength-division-multiplexing (WDM) transmission system using optical fiber amplifiers is demonstrated for the first time. The system supervision by an optical time domain reflectometer (OTDR) is achieved without degrading the 2.5 Gb/s service over a bidirectional six-WDM-channel 200-km single-fiber link. Negligible system penalties of dispersion and counter-directional transmission crosstalk are observed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Adaptive inverse filters for stereophonic sound reproduction

A general theoretical basis for the design of adaptive digital filters used for the equalization of the response of multichannel sound reproduction systems is described. The approach is applied to the two-channel case and then extended to deal with arbitrary numbers of channels. The intention is to equalize not only the response of the loudspeakers and the listening room but also the crosstalk transmission from right loudspeaker to left ear and vice versa. The formulation is a generalization of the Atal-Schroeder crosstalk canceler. However, the use of a least-squares approach to the digital filter design and of appropriate modeling delays potentially allows the effective equalization of nonminimum phase components in the transmission path. A stochastic gradient algorithm which facilitates the adaptation of the digital filters to the optimal solution, thereby providing the possibility of designing the filters in situ, is presented. Some experimental results for the two-channel case are given. >

A Cost Effective PI Network Filter for Elimination of Stiff Transmission Crosstalk in Zero Sequence Propogated Distribution Power Line Carrier Signals

A cost effective method for elimination of intersubstation crosstalk problem in distribution power line carrier communications systems is presented. A shunt three-phase wye-configured capacitor bank is connected between a substation transformer and any source of zero-sequence power line carrier commu nication signals being transmitted on the substation distribution network to partially alleviate unbalance conditions in the communication signals. When balan ced, these signals are not passed by a three-phase delta-wye grounded substation transformer to the main transmission line. The signal is further attenuated by connecting the common wye-point of the capacitor bank through an inductance to neutral. This forms a shunt element of either an L or pi attentuation circuit with the series inductance of the substation transformer and the transmission line inductance. The transformer series inductance and the transmission line form the serial elements of the L or pi circuit. A further shunt element at another substation distribution network completes the attenuation circuit for the pi configuration. The method was verified in an actual field application. The cost of this method is shown to be only one-fifth that of the conventional approach.

A Cost-Effective Pi Network Filter for Elimination of Stiff Transmission Crosstalk in Zero Sequence Propagated Distribution Power Line Carrier Signals

A Cost-Effective Pi Network Filter for Elimination of Stiff Transmission Crosstalk in Zero Sequence Propagated Distribution Power Line Carrier Signals