Ribbon Cable Research Articles

Thermal conductance at millikelvin temperatures of woven ribbon cable with phosphor-bronze clad superconducting wires

Woven Nomex® ribbon cables made up with superconducting niobium–titanium wire are used at millikelvin temperatures in many large cryogenic instruments. It is important to know how much heat in transmitted down such cables. However, the conductivity of the materials used is not well known. Another problem is that the wires are normally clad with alloys which exhibit some magnetism. This is a potential problem for instruments employing superconducting detectors. A safe non-magnetic alternative to the usual materials is phosphor-bronze clad niobium–titanium wiring. However, there is little experience with such wires. We have therefore measured the conductance of a ribbon cable made up with these wires. The measured values are in good agreement with our predictions, suggesting that the values we have used to model the cable are sufficiently accurate, and could therefore be used to predict the performance of ribbon cables using other cladding materials, so long as the conductivity of the cladding is reasonably well known. As part of our analysis, we consider the likely variation in thermal conductivity values for C51000 phosphor bronze caused by legitimate variations in composition.

Fast time domain reflectometry (TDR) measurement approach for investigating the liquefaction of soils

Time domain reflectometry (TDR) was used for the spatial observation of transient density changes in a laboratory shake-box apparatus. Shake-box experiments are conducted to investigate the liquefaction of soils due to seismic excitation. As a sensor, a flat ribbon cable was placed within a water saturated sand column two metres in height. In the experiment, the soil column was excited at its base with a sinusoidal signal with low frequencies and moderate amplitudes. During the tests, TDR measurements were conducted with a repetition rate of 30 s−1. Temporal density changes during the liquefaction and reconsolidation process of the quartz sand along the sensor could be shown through signal analysis. The mean porosities calculated from the relative dielectric permittivity using a soil-specific calibration function could be determined with an RMSD-value of 0.02 compared to the porosities determined from the height of the sample. With the metrological set-up for the TDR measurements being used, fast temporal changes in the density profile could be qualitatively visualized indicating the movement of the reconsolidation front during the liquefaction.

Temperature distribution of read/write head soldering with ribbon cable of HDD

In the present paper, the temperature distribution of the read/write head soldering with the ribbon cable of the HDD is presented. The soldering of the actuator/connector with the ribbon cable can be performed either by manual or semi-automatic process which has been introduced as one of the manufacturing processes of the HDD. Finite element analysis is applied to analyze the model. The properties of the soldering ball and boundary conditions have significant effects on the thermal stress and localized heat in the soldering process that cause the failure of the ribbon cable of the HDD. The results of this study are of technological importance for the efficient design and/or approval of the soldering HDD process to reduce yield loss of the hard disk drive.

Spatial time domain reflectometry and its application for the measurement of water content distributions along flat ribbon cables in a full‐scale levee model

Spatial time domain reflectometry (spatial TDR) is a new measurement method for determining water content profiles along elongated probes (transmission lines). The method is based on the inverse modeling of TDR reflectograms using an optimization algorithm. By means of using flat ribbon cables it is possible to take two independent TDR measurements from both ends of the probe, which are used to improve the spatial information content of the optimization results and to consider effects caused by electrical conductivity. The method has been used for monitoring water content distributions on a full‐scale levee model made of well‐graded clean sand. Flood simulation tests, irrigation tests, and long‐term observations were carried out on the model. The results show that spatial TDR is able to determine water content distributions with an accuracy of the spatial resolution of about ±3 cm compared to pore pressure measurements and an average deviation of ±2 vol % compared to measurements made using another independent TDR measurement system.

High-density cochlear implants with position sensing and control

Silicon-based thin-film technology has been used to develop high-density cochlear electrode arrays with up to 32 sites and four parallel channels of simultaneous stimulation. The lithographically-defined arrays utilize a silicon-dielectric-metal-parylene structure with 180μm-diameter IrO sites on 250 μm centers. Eight on-board strain gauges allow real-time imaging of array shape during insertion, and a tip sensor measures forces on any structures contacted in the scala tympani (e.g., the basilar membrane). The array can be pre-stressed to hug the modiolus, which provides position reference. Tip position can be resolved to better than 50 μm. Circuitry mounted on the base of the array generates stimulating currents, records intra-cochlear responses and position information, and interfaces with a custom microcontroller and inductively-coupled wireless interface over an eight-lead ribbon cable. The circuitry delivers biphasic 500 μA current pulses with 4 μA resolution and a minimum pulse width of 4 μs. Multiple sites can be driven in parallel to provide higher current levels. Backing structures and articulated insertion tools are being developed for dynamic closed-loop insertion control.

Effect of cabling on polarization mode dispersion in optical fiber ribbon cables

This paper theoretically and experimentally investigates an effect of cabling on polarization mode dispersion (PMD) in ribbon fibers helically stranded in optical fiber ribbon cables aimed at designing low PMD ribbon cables. Based on the birefringence model focused on the change in the birefringence when ribbon fibers are cabled, the helical pitch of optical fiber ribbon cables is designed to minimize the maximum PMD in the cables. A low PMD characteristic is confirmed in optical fiber ribbon cable with approximately the optimal helical pitch.

QSFP specification expands to support 40 Gb/s applications [QSFP

The Quad Small Form Factor Pluggable (QSFP) specification is complete, and vendors have released modules, connectors, and cages that support up to 40 Gb/s/port. Each QSFP port currently support four independent channels with speeds up to 10 Gb/s/channel, and optical modules are expected to support these speeds in the near future. Passive cables combined with QSFP connectors and cages are already running at 10 Gb/s in backplane and shortreach applications. QSFP optical modules running to 5 Gb/s are currently in production, and 8 and 10 Gb/s modules are expected in late 2007. With the QSFP packing four independent optical channels via an MPO 12fiber ribbon cable for 40 Gb/s applications, the QSFP module offers the highest pluggable bandwidth density in the world. The QSFP is designed for many applications including Ethernet, Fibre Channel, InfiniBand, and synchronous digital hierarchy/synchronous optical network (SDH/SONET). QSFP spans 1‐10 Gb Ethernet applications as well as 1, 2, 4, 8, and 10GFC applications for Fibre Channel. The QSFP is also being proposed for the emerging 20 and 40GFC applications that are being defined for Fibre Channel ganged links. With InfiniBand primarily using quad links, QSFP is suited for single data rate (SDR at 2.5 Gb/s/channel), double data rate (DDR at 5 Gb/s/channel), and quad data rate (QDR at 10 Gb/s/channel). In the telecom space, the QSFP is applicable to OC-3, OC12, OC-48, and OC-192 speeds. Each channel of the QSFP module can run independently or in parallel, depending on the application, to support bandwidth to 40 Gb/s. The QSFP module combines the best features of the SFP and XFP modules. The QSFP was originally designed to replace four SFP modules running up to 5 Gb/s by using an MPO 12-fiber ribbon connector. Although the electrical connector for the module supported 10 Gb/s from the start, the module vendors doubted that 10 Gb/s speeds could be supported in a module that dissipated less than 3.5 W of power in the small package. With recent reductions in integrated circuit (IC) power consumption and the desire to support higher speeds, the module vendors agreed to open up the throttle on the specification so that 10 Gb/s modules can be supported in short-reach applications. The QSFP module borrows heavily from the XFP specification and uses a similar latching mechanism, cage, and memory map, but does not include a retimer of the XFP to keep the modules low cost. Supporting speeds up to 10 Gb/s/channel, the QSFP can also replace four SFP+ modules, which replace the SFP at speeds above 4 Gb/s. Several modifications were needed for the QSFP to support the four channels through its pluggable 38-pin electrical connector. While the SFP has separate connections for LOS, Rate Select, TxFault and Tx Disable, the QSFP could not support 16 pins for these functions when 16 pins are required for the high-speed differential signals and 12 more for grounding. Individual channel controls were incorporated into the processor on the module for control and digital diagnostics. The sophistication of the two-wire serial interface to the transceiver is significantly more complex than previous single-channel transceivers since multiple channels need to be controlled through the single interface. Through the combined efforts of the consumers and supplier of the QSFP, the QSFP specification has yielded a valuable solution that meets the highspeed and high-density needs of the networking community. Some users are finding QSFP to be very effective in dense backplane applications where passive copper cables can be used to interconnect the QSFP cages. When longer distances are required in the application, optical QSFP modules can replace these passive copper cables to increase scalability of the implementation. With density and speed being pushed to the limits, the QSFP solution relieves the pressures that have been building up in networking applications. For more information on QSFP, please visit http://www.qsfpmsa.org.

A Shuttered Neural Probe With On-Chip Flowmeters for Chronic In Vivo Drug Delivery

This paper describes the development of shutters, fluidic ribbon cables, and flowmeters for use on bulk-micromachined neural probes. The resulting devices permit electrical recording, stimulation, and chemical drug delivery in the central nervous system at the cellular level. Dielectric shutters reduce unintended drug delivery by a factor of about 25 compared with an open orifice, while silicon fluidic cables are 1.5 times more flexible than the 70 mum-ID polyimide tubing previously used. A pulsed thermal flowmeter integrated on the probe allows verification of drug delivery on a per-channel basis with a resolution of 150 pL/s. Thermal time constants are about 60 mus, allowing multiple measurements within one delivery pulse while restricting any tissue heating to negligible levels. Finally, test structures have shown the process compatibility of on-chip thermopneumatic microvalves and micropumps. The fabrication of these fluidic structures (microchannels, shutters, cables, valves, and pumps) requires only two masks in addition to the eight normally used for passive probes, providing important new capabilities for use in neurophysiological research and neural prostheses

Exposure of NIF Relevant Polymeric Samples to Deuterium-Tritium Gas at Elevated Temperature and Pressure

The purpose of the experiments described in this paper was to expose samples of polymeric materials to a mixture of deuterium-tritium (DT) gas at elevated temperature and pressure to investigate the effects (i.e., damage) on the materials. The materials and exposure parameters were chosen to be relevant to proposed uses of similar materials in inertial fusion ignition experiments at the National Ignition Facility. Two types of samples were exposed and tested. The first type consisted of 10 4-lead ribbon cables of fine manganin wire insulated with polyimide. Wires of this type are proposed for use in thermal shimming of hohlraums and the goal of this experiment was to measure the change in electrical resistance of the insulation due to tritium exposure. The second type of sample consisted of 20 planar polymer samples that may be used as ignition capsule materials. The exposure was at 34.5 GPa (5010 psia) and 70°C for 48 h. The change in electrical resistance of the wire insulation will be presented. The results for capsule materials will be presented in a separate paper in this issue.

Coating failure in the pull-out of a multiply-coated optical fiber

For fiber optic ribbon cables, stripping of the multiple coatings from the optical fiber glass is an important step in installation. During this process, failures that lead to excess residue on the fiber create extra work that is costly. In this paper, we describe a systematic experimental approach to understanding the failure mechanism observed during fiber optic ribbon stripping. The blades in the ribbon-stripping tool create compressive stresses during the fiber pull-out process. These compressive stresses, in turn, may lead to coating instability. The coating instability creates potential for stress risers and excessive wear of the innermost coating. Reducing the length of the stripping sample has been found to significantly reduce the occurrence of this failure mode.

Mechanical Characterization and Design of Flexible Silicon Microstructures

A variety of different silicon structures has been fabricated and characterized mechanically to optimize the design of silicon ribbon cables used in neural probes and multichip packaging structures. Boron-doped 3-/spl mu/m-thick silicon beams were tested in three modes: bending in plane, twisting (along beam axis), and pushing. Various cable configurations were investigated (straight beams, curved beams, meandered beams, etc.) as well the effects of length, width, cable termination, and the presence of reinforcing spans between multistranded cables. The results along with finite element modeling indicated that many simple modifications could be made to increase the strength and flexibility of silicon ribbon cables. One structure, a meandered beam 200-/spl mu/m wide and 2-mm long could be twisted up to 712/spl deg/. It also was seen that structures having multiple 20-/spl mu/m-wide beams were generally more robust than those with a single 500-/spl mu/m-wide beam. Finally, a method for easy determination of the bending fracture strain is analyzed and verified. It was seen that the silicon structures tested broke after a strain slightly above 2%.

Experience with parallel optical link for the CDF silicon detector

The Dense Optical Interface Module is a byte-wide optical link developed for the Run II upgrade of the CDF silicon tracking system (CDF Collaboration, The CDF-II Detector Technical Design Report, FERMILAB-Pub 96/390-E; S. Nahn, status of CDF silicon, Vertex 2002, Nucl. Instr. and Meth.). The module consists of a transmitter with a laser-diode array for conversion of digitized detector signals into light outputs, a 22 m optical fiber ribbon cable for light transmission, and a receiver converting the light pulses back to electrical signals. We report on the design feature, characteristics, and radiation tolerance.

Active waveguide devices by Ag–Na ion exchange on erbium–ytterbium doped phosphate glasses

Arrays of buried channel waveguide lasers and amplifiers were fabricated by silver–sodium ion exchange in erbium–ytterbium doped phosphate glass substrates. The fabrication process, consisting of a thermal diffusion from fused salt followed by a field-assisted burial step, is optimized to get single-mode channel arrays fully compatible with standard single-mode fibres and fibre ribbon cables. The active channels were successfully tested realizing both lasers and amplifiers in the C-band suitable for optical communications. Erbium waveguide lasers exhibit a maximum output power of ∼1.7 mW and erbium-doped waveguide amplifiers provide a maximum internal gain of ∼11.3 dB at 1534 nm.

Multiwavelength parallel optical interconnects for massively parallel processing

We describe a multiwavelength, multifiber (parallel) optical interconnect based on multimode fiber ribbon cables with applications in massively parallel processing systems. By combining the benefits of parallel optics and coarse wavelength division multiplexing high aggregate throughputs are possible in a broadcast and select architecture that provides a single hop to all nodes. We identify the key components needed for such a system and report on our component development efforts for multiwavelength parallel optical interconnects. System components reported herein include a four-wavelength bit-parallel transmitter using a silicon optical bench and hybrid packaging, and two-port and three-port wavelength selective filter modules packaged to be compatible with mechanically transferable ferrule terminated ribbon cables. The transmitters were modulated up to 1.25 Gb/s with a bit-error rate better than 10/sup -12/ and no measurable power penalty due to multiple wavelength bit parallel operation. The filters exhibited insertion losses of between 1 and 2 dB and would support 10 nm spaced channels at -23-dB crosstalk.

Optical Interconnect Cabling for Next Generation Central Office Switching

Conventional interconnect cabling is inadequate to handle the terabit speed requirements of switching and routing in the Central Office. In this paper, we propose a solution of parallel optical channels that consist of a flat ribbon cable, with 24 multimode fibers and a special matching 24-pin fiber-array connector that feeds 12 VCSE transmitters and 12 receivers. The 24-fiber flat ribbon design provides greater fiber density and smaller bend radius than conventional cables. In addition, the 24-fiber flat ribbon meets all environmental tests.

Analysis and design of ribbon cables for high-speed digital applications

Ribbon cables have been widely used as subsystem interconnections in a large number of digital systems, because they can convey numerous bits of a digital signal simultaneously. In this article, finite difference and finite difference time domain (FDTD) methods are used to analyze and optimize the electrostatic analysis design of ribbon cables, and measurements are used to verify the numerical results. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 148–158, 2002.

Focus on Data Acquisition

Focus on Data Acquisition

Dense Optical-electrical Interface Module

The DOIM (Dense Optical-electrical Interface Modules) is a custom-designed optical data transmission module employed in the upgrade of Silicon Vertex Detector of CDF experiment at Fermilab. Each DOIM module consists a transmitter(TX) converting electrical differential input signals to optical outputs, a middle segment of jacketed fiber ribbon cable, and a receiver (RX) which senses the light inputs and converts them back to electrical signals. The targeted operational frequency is 53 MHz, and higher rate is achievable. This article outlines the design goals, implementation methods, production test results, and radiation hardness tests of these modules.

Analysis of the polarization evolution in a ribbon cable using high-resolution coherent OFDR

Exploiting the inherent polarization dependence and good spatial resolution of optical frequency domain reflectometry (OFDR), the beatlength in a ribbon fiber can be straightforwardly measured. The results clearly show the different amount of polarization ordering for inner and outer ribbon fibers due to the stress-induced birefringence from the common outer coating.

Construction of a very high-density extracellular electrode array.

Cellular activation mapping (specifying in time and space the electrical activation sequence of cells) is a well-established basic research tool in cardiac, neural, and gastric physiology. Much recent research in cardiac mapping has focused on large arrays (>200 electrodes) with small electrodes (<500 microm). Construction of such arrays using standard techniques is tedious and yields irregular electrode spacing. We present a novel construction technique that rapidly produces large arrays with regularly spaced small electrodes. For methods, fine-pitch copper ribbon cables, insulated with either polyvinylchloride (PVC) or polyimide (flexible printed circuit; FPC), were assembled together such that the active surface was the cut end of the cable. The cut end was sanded and polished, then coated with silver and sometimes silver chloride. Once completed, the alternating current (AC) root-mean-square (rms) potential was measured between two adjacent, individual electrodes. Polarization testing was conducted according to a previously reported protocol (Witkowski FX and Penkoske PA. J Electrocardiol 21: 273-282, 1988). Activation mapping was conducted in the open-chest guinea pig with both pacing- and defibrillation- strength stimuli. In terms of results, four PVC and three FPC arrays were constructed, ranging from 4 to 400 electrodes. Two hours of labor were needed to create a complete electrode array, independent of the number of electrodes, including connectors and silver/silver chloride coating. As expected, the addition of a silver/silver chloride coating significantly reduced (0.76-0.42 mV, P < 0.001) the AC rms potential difference between two electrodes. A nearly immediate recovery of the potential difference between adjacent pairs of silver/silver chloride electrodes was observed after defibrillation stimuli.