Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 29
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 4 Electronics and Electrical Engineering Laboratory PANEL MEMBERS Gregory E. Stillman, University of Illinois, Chair B. Jayant Baliga, North Carolina State University Dennis D. Buss, Analog Devices Blas Cabrera, Stanford University Esther M. Conwell, Xerox Webster Research Center Gary M. Davidson, TRW Space and Defense Sector Daniel F. DiFonzo, Planar Communications Corporation John V. Evans, COMSAT Laboratories Douglas K. Finnemore, Iowa State University William J. Gallagher, IBM T.J. Watson Research Center H. R. Hoffmann, AT&T Bell Laboratories Richard M. Josephs, Innovative Instrumentation, Inc. Felix P. Kapron, Bellcore Frederick J. Leonberger, United Technologies Photonics, Inc. George A. Maneatis, Pacific Gas & Electric Company (retired) Arthur A. Oliner, Polytechnic University (retired) Don Parker, Hughes Aircraft Company D. Howard Phillips, Semiconductor Research Corporation Robert Stratton, Texas Instruments Incorporated T. Peter Sylvan, Teradyne, Inc. Hugo vifian, Hewlett Packard Company Invited Participants E. D. (Sonny) Maynard, Jr., EDM Strategies, Inc. V. Thomas Rhyne, MCC Thomas Shaffner, Texas Instruments Incorporated Submitted for the panel by its Chair, Gregory E. Stillman, this assessment of the fiscal year 1993 activities of the Electronics and Electrical Engineering Laboratory is based on site visits by individual panel members, a formal meeting of the panel on May 5-7, 1993, in Boulder, Colorado, and the annual report of the laboratory. LABORATORY OVERVIEW Mission The mission of the Electronics and Electrical Engineering Laboratory (EEEL) is to improve U.S. economic competitiveness, government operations, and public health and safety by providing essential measurement infrastructure, generic technology, and fundamental research in electronics and electrical phenomena of importance to industry, government, and scientific and
OCR for page 30
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 engineering communities. EEEL develops and disseminates measurement methods, theory, measurement reference standards (including the national primary standards for electricity, and materials reference standards), and calibration services to assure measurement traceability. Methodology and standards for measuring electronic and electrical materials, components, equipment, and systems operating over the electromagnetic frequency range from direct current to light are developed to the accuracy needed for research and development, manufacturing, marketplace exchange, and the operation of electronic and electrical products. Strategy EEEL's goal is to be the world's best source of fundamental and industrial reference measurement methods and physical standards for electrotechnology. To achieve this goal and to obtain optimum leverage in the context of NIST' s mission, EEEL stresses the provision of measurement infrastructure rather than the development of generic technology. EEEL argues that its measurement research and development leads naturally to substantial commercialization; e.g., at least 50 companies are known to have commercialized EEEL's results since 1978. EEEL's current strategic plan, Measurements for Competitiveness in Electronics (NISTIR 4853; U.S. Department of Commerce, Washington, D.C., April 1993), is a revision of an earlier plan. To ensure relevance and validity, the plan was reviewed by industry. Because of the immense range of industry's needs compared with EEEL's limited resources, EEEL's plan also includes criteria for project selection and interaction with industry to select projects. EEEL plans to update its strategic plan again as soon as NIST has revised its strategic plan to reflect the Clinton administration's new role for NIST. Based on EEEL's planning, increases in the fiscal year 1994 budget will be applied to work in semiconductors, microwaves, fundamental quantum standards, high-speed electrical and optical components, electronic data exchange for automated manufacturing, and digital imaging. NIST's fiscal year 1994 budget also includes initial funding for a NIST-wide magnetics program. The panel endorses EEEL's strategic planning process but notes that EEEL's aspirations far exceed its likely resources. Resources Funding EEEL's operating budget for fiscal year 1993 was $44.3 million (up $3 million from fiscal year 1992). $24.3 million was appropriated by Congress for Scientific and Technical Research and Services (STRS), an increase of $1.7 million over fiscal year
OCR for page 31
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 1992. Congressionally appropriated funding is the only funding on which EEEL can base long-term plans. NIST's Advanced Technology Program (ATP) provided EEEL significant additional funding in fiscal year 1993 to develop technical capabilities beneficial to ATP projects. ATP funds are of one to a few years' duration. EEEL calibrations, which account for about 42 percent of NIST's total calibration service in dollars, provided an income of $2.2 million in fiscal year 1992, down about 15 percent from the previous year. Other federal agencies, primarily the Department of Defense (DOD), provided $15.8 million in fiscal year 1993. Some of these other-agency (OA) funds were passed on to other NIST laboratories; the Office of Microelectronics Programs received $1.6 million to manage a NIST-wide semiconductor program, and the Office of Law Enforcement Standards received $0.1 million to manage another NIST-wide program. EEEL's distribution of STRS funding among its divisions remains a matter of concern to the panel and EEEL management. For example, STRS funding provides only 32 percent of the Electromagnetic Fields Division' s total budget. EEEL attempted to increase the division's STRS funding through NIST's budget process in fiscal years 1992 and 1993 and plans to try to increase it again in fiscal year 1994. Staff EEEL entered fiscal year 1993 with a total staff of 354, with 67 percent professionals, about 51 percent of whom were at the PhD level. While EEEL's total staff count remained essentially unchanged (EEEL lost six senior-level full-time permanent staff members and gained eight), the number of professionals increased by six and the number of PhDs by seven. Forty-five guest scientists and industrial research associates were stationed in EEEL's laboratories. EEEL's staff count has remained stable for several years. EEEL's staff received a NIST Crittenden Award plus six Department of Commerce Bronze Medals and one Silver Medal during fiscal year 1992. External recognition included Institute of Electrical and Electronics Engineers Fellow awards to four EEEL staff members, awards for best paper and for various other outstanding accomplishments, invitations to present papers, and prestigious committee appointments.
OCR for page 32
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 ASSESSMENT OF STRATEGY AND PANEL'S RECOMMENDATIONS--FISCAL YEAR 1993 Comments on Strategy EEEL strategies far outstrip the resources likely to be available to EEEL. The Electricity Division, a keystone division of EEEL, is not sufficiently emphasized in EEEL's strategic plan, nor is the significance of its work clearly represented in Measurements for Competitiveness in Electronics (NISTIR 4583, April 1993). Strategic planning for such things as impact on intrinsic standards and laboratory accreditation is inadequate or missing. Such important services as instrumentation calibration and traceability to NIST units of measure are buried in the complex systems testing category rather than highlighted in the strategic plan. Recommendations As well as refine its process for selecting and funding new projects, EEEL should plan to phase out or terminate projects. EEEL should become a node on the Electric Power Research Institute 's EPRINet to facilitate the work of the Applied Electrical Measurements Group. (The Panel notes that EEEL's research groups and researchers are becoming much more aware of who is interested in their research projects and why.) ASSESSMENT OF DIVISION PROGRAMS The EEEL consists of the Electricity Division and the Semiconductor Electronics Division, located at Gaithersburg, Maryland; the Electromagnetic Fields Division and the Electromagnetic Technology Division, located at Boulder, Colorado; and the Office of Microelectronics Programs and the Office of Law Enforcement Standards, located in Gaithersburg (Figure 4.1). The Office of Microelectronics Programs manages a NIST-wide response to the semiconductor industry's needs for measurement methods and data. The Office of Law Enforcement Standards provides NIST-wide technical services to the U.S. Department of Justice, to state and local governments, and to selected other agencies in support of law enforcement activities. The panel reviewed the programs of the above offices but did not formally assess their performance.
OCR for page 33
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 FIGURE 4.1 Organization and structure of NIST's Electronics and Electrical Engineering Laboratory.
OCR for page 34
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 Electricity Division Mission The EEEL's Electricity Division consists of the Electrical Reference Standards Group, the Fundamental Electrical Measurements Group, the Applied Electrical Measurements Group, and the Electronic Instrumentation and Metrology Group. The Electricity Division maintains and improves the national standards of electrical measurement; develops stable electrical standards for the dissemination of the units of electrical measure and disseminates such units; conducts experiments to realize the electrical units in terms of the International System of Units (SI units); determines fundamental physical constants related to electrical units; develops and evaluates measurement methods and services to support electrical materials, components, instruments, and systems used for the generation, transmission, and detection of conducted electrical signals and energy; conducts research and develops measurement and calibration methods and measuring instruments for use in the laboratory, on the production line, in the marketplace, and in the field; develops numerical data required for understanding the fundamental electrical phenomena and for the application and specification of electrical systems and their components and for the interpretation of resulting measurements; disseminates and fosters application of the research and development outputs for the marketplace exchange of electrical and electronic components, modules, and instruments, and for the enhancement of performance and reliability of the systems in which they are applied; assists in applying scientific and technological development to measurement problems in industry, science, and other areas of NIST research; and in certain areas, such as digital imaging and product description in digital form, develops and provides the technical base in support of consensus standards. Panel's Findings, Conclusions, and Recommendations--Fiscal Year 1993 Division Funding. Adequate STRS funding is a continual concern of the Electricity Division. Core funds have been relatively flat, without adjustments for inflation, for several years. Of more significance is the rapid reduction in support provided by the DOD for calibrations (nearly 50 percent for the division from fiscal year 1992 to fiscal year 1993). Alternate support is needed to maintain the division's calibration services. Calibration Laboratory Accreditation. NIST's National Voluntary Laboratory Accreditation Program (NVLAP) for accrediting U.S. measurement laboratories is based in part on technical input from the Electricity Division. NVLAP removes nontariff trade
OCR for page 35
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 barriers, thus improving international competitiveness, and reduces the costs of testing U.S. products and services. The relationship between the Electricity Division and NVLAP for providing technical direction for NVLAP has not been formalized, even though the Electricity Division must make recommendations that (1) are acceptable internationally and to government agencies, (2) do not go beyond minimum requirements, and (3) add value to the accreditation. To add value, the accreditation must be cost-effective and affordable and must maintain or improve the U.S. measurement system. Division Quality Improvement Program. The Electricity Division lacks a documented or consistent quality improvement program. Quality improvement programs in industry improve measurement assurance, competitiveness, effectiveness of research and development activities, and the quality of goods and services. Electrical Reference Standards Group. The Electrical Reference Standards Group maintains national physical standards for electrical measurement, provides measurement services for basic electrical units, and develops stable standards and measurement methods for dissemination of electrical units. The group develops standards for and calibrates instruments for measuring direct current (dc) voltage, resistance, and impedance, and alternating current (ac)/dc difference; maintains the Measurement Assurance Program for dc voltage, resistance, and capacitance, and ac/dc difference calibrations; and improves physical measurement standards and calibration methods as needed by industry and science. Strategies. The Electrical Reference Standards Group maintains and advances basic standards to meet such continuing needs of industry, government, and academia as reducing measurement uncertainties, improving stability, and extending the range of services. Although the group anticipates user needs through participation in industry associations, frequent visits to cliental laboratories, and response to industry surveys, meeting those needs in a timely manner is not always possible due to limited resources. Resources. Although the staff of the Electrical Reference Standards Group is competent and enthusiastic, morale has suffered as a result of funding uncertainties and changes in NIST's charter. The staff has been reduced, and the technical breadth of services provided by the group has increased. Some of the important nationwide services provided by this group depend on a single individual. Should that individual leave, retire, or transfer, the services would be jeopardized. It is evident that the staff is spread too thin.
OCR for page 36
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 Measurement Services. Despite limited resources, significant improvements are being made by the Electrical Reference Standards Group in the delivery of measurement services. The Impedance Measurement Program, which was on the verge of not being able to perform due to obsolete and unrepairable equipment, has been modernized, and its services are no longer at risk. The Capacitance Measurement Assurance Program, discontinued several years ago due to loss of capability, has been upgraded and reintroduced to improve capacitance measurements in industry. Gains being made in ac/dc transfer standards promise to reduce ac/dc transfer uncertainties at 1 MHz from 70 ppm to, possibly, 10 ppm. Acquisition of a workstation has improved design capability. The latest designs might be applicable for use in the front end of digital multimeters. This would allow ac accuracies in digital multimeters to approach dc accuracies--a major breakthrough. Resistance Standards and measurement methods in the trillion (tera)-ohm range and ac resistance are both progressing. Services in this area are nonexistent or inadequate, even though these measurements are commonplace in industry. Intrinsic Standards. Within the next 20 years, intrinsic standards (standards based on natural phenomena) will be commonplace in industry's calibration laboratories. As intrinsic standards evolve, the role of the Electrical Reference Standards Group will have to be examined. Intrinsic standards for voltage measurements are, on the one hand, already reducing industry 's dependence on NIST; if, on the other hand, the sophisticated instrumentation involved is not properly set up or operated, degradation of the U.S. measurement system could result. Measurement assurance methodology will be needed to ensure that measurement system degradation does not occur. NIST must continue to maintain traceability to basic units of measurement while intrinsic standards are being incorporated. The dilemma is that NIST's funding for providing calibration services will be reduced as industrial dependence decreases. ac-dc Difference Standards and Measurement Techniques. The Electrical Reference Standards Group finished the design of and fabricated eight newly conceived thin-film micropotentiometers. The instrument is being redesigned for improved performance. The group also designed three new single-voltage-range micropotentiometers with trifilar heaters and a new multirange device. Production and testing of new low-capacitance, thin-film multijunction thermal converters were completed. These developments should lead to commercial applications in digital multimeter instrumentation that could increase measurement accuracies by an order of magnitude or more. Resistance Standards and Measurements. The Electrical Reference Standards Group made the first measurements of three
OCR for page 37
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 quantum Hall effect specimen devices using the new system installed in the group's resistance calibration laboratory. It also completed, tested, and calibrated the new inductive voltage divider for ac resistors. The bridge's binary inductive voltage dividers were calibrated, giving corrections of less than 0.05 ppm at 100 Hz and 0.12 ppm at 1 kHz. Group staff discovered that variance in resistance in standards common to industry due to the pressure coefficient is significant in laboratories trying to maintain standards in the uncertainty range of 0.2 to 0.3 ppm. An altitude change of 1 mile can vary the resistance by as much as 0.1 ppm. Fundamental Electrical Measurements Group Mission and Objectives. The Fundamental Electrical Measurements Group realizes electrical units in terms of the SI units, determines fundamental constants as related to electrical units, and maintains electrical units in terms of intrinsic standards, which in turn are based on fundamental constants. The group currently maintains and improves the electrical units of capacitance (farad), resistance (ohm), current (ampere), and voltage (volt). In addition, the group improves the fundamental understanding of the U.S. system of units by testing their self-consistency through precise experiments, such as the measurement of the gyromagnetic moment of the proton. Fundamental electrical measurement services provide the underlying traceability for all U.S. electrical measurement standards and must form a strong base for commercial electronic instrumentation in the United States if the nation is to compete with high-technology countries such as Germany and Japan. Strategy. The centerpiece of the Fundamental Electrical Measurements Group 's strategy for meeting its program objectives is the quantum standards and research initiative, proposed by the EEEL to establish a new generation of standards, i.e., intrinsic standards based directly on quantum mechanical physical quantities. Additional research will be done to understand why the accuracy of the quantum Hall effect resistance is so high as well as to develop guidelines for the maintenance of this new standard. Work currently under way in the Fundamental Electrical Measurements Group, as well as the Cryoelectronic Metrology Group in the Electromagnetic Technology Division at NIST Boulder, may lead to quantum standards for capacitance and for current that are similar to those already developed for voltage and resistance. Status and Progress. The internationally recognized Fundamental Electrical Measurements Group maintains the devices and techniques that form the basis for all units of electrical measures used throughout the United States. Group staff lead the
OCR for page 38
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 world in several of the group's measurement techniques and in the precision and accuracy of a number of instruments and devices. The farad is known through the calculable capacitor at the 0.01-ppm level. The ohm standard is a room-temperature resistor known at the 0.03-ppm level. Good progress is being made on maintaining the U.S. ohm standard via the quantum Hall effect. Progress has continued on improving quantum Hall effect devices for resistance measurements. The comparison of resistance measurements made with a quantum Hall effect device made of GaAs compared with measurements taken with a device made of silicon (in the form of a metal oxide semiconductor field-effect transistor) agreed within 4 parts in 10 billion. The project to determine the ampere directly from the definition of SI units is progressing well. A factor-of-3 improvement has been obtained over fiscal year 1992, and the SI-based direct ampere is now known to a level of 0.1 ppm. A strong effort is under way to investigate single-electron tunneling devices for current standards. Thin-film devices are being made at the Cornell National Nanofabrication Facility and in collaboration with the Cryoelectronic Metrology Group. As this program matures, it is likely to lead to a quantum current standard that could be used in conjunction with the SI ampere apparatus, much as in the case of the relationship between the quantum Hall effect resistance and the ohm. Josephson junction arrays define the volt in terms of frequency. A comparison of voltage standards using NIST's Josephson junction arrays with an array voltage standard at the International Bureau of Weights and Measures indicated an agreement at the 0.1-ppb level, an impressive result. This research is coordinated with voltage calibrations by the division's Electrical Reference Standards Group based on zener diode secondary standards. In addition, a strong tie exists with the Cryoelectronic Metrology Group, the source of successful 10-V Josephson array standards. The commercialization of this technology is being realized through collaboration with industry; however, much research is still necessary to better understand Josephson arrays and to develop additional applications such as ac volt measurements, ratios, and microwave couplings. Also, research on the use of high-temperature superconductors for Josephson junctions could lead to junctions that operate at liquid-nitrogen temperatures. Research on quantum standards in the Fundamental Electrical Measurements Group could lead to a quantum-based kilogram, thus removing the last of the artifacts from the primary standards. Despite the development of intrinsic standards, artifacts will continue to be used as secondary standards whenever the cost of the intrinsic primary standards is high. The secondary standards will be calibrated against the quantum standards to eliminate drift in the values over time, as occurred, e.g., in the case of the ohm.
OCR for page 39
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 Resources. The trend over the last decade toward full rather than incremental cost recovery for calibration services has placed a significant fraction of the fundamental standards program on “soft” support. The decreases in defense spending have resulted in about a 50 percent reduction in resources for coordinating calibrations and threaten to force staff reductions in the maintenance of critical standards. Also, each of the quantum standards research projects is underfunded. Recommendations Fundamental electrical measurements should be more visible in EEEL 's strategic plan. Currently, fundamental electrical measurements are hidden under the complex systems testing category. Categories such as “Instrument Calibration Services” and “Traceability to NIST Units” should be added to the strategic plan. A comprehensive section should be added to Measurements for Competitiveness in Electronics (NISTIR 4583, April 1993) on the NIST electrical calibration services and on the traceability of units to NIST standards. As the Panel recommended in its fiscal year 1991 report, a Fundamental Constants Committee should be formed to coordinate fundamental constants work NIST-wide. Committee membership should include staff from the Fundamental Electrical Measurements Group, the Cryoelectronic Metrology Group, and the Time and Frequency Division of the Physics Laboratory, as well as from NIST's Standard Reference Data Program and the division 's Precision Measurement Grant Program, and should establish a working subgroup for the maintenance of the fundamental constants. An annual report should highlight progress made in the research and instrumentation and publicize Precision Measurement Grant selections and results. In addition, the committee should sponsor conferences and workshops for the wider scientific and standards communities. (A third conference in the Precision Measurement and Fundamental Constants series is overdue. The first two conferences of the series occurred in 1970 and 1981.) Applied Electrical Measurements Group Mission and Objectives. The Applied Electrical Measurements Group develops theory, methods, and physical standards for the measurement of electrical quantities in advanced high-voltage and high-power systems and contributes to measurements and performance standards required for digital imaging and electronic product specification. The group is currently adopting a broader role that includes video standards, product data exchange, and automated electronic
OCR for page 54
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 superconductivity to electronics. Both of the division's superconductor programs have a prominent role in the NIST-wide program of research on high-temperature ceramic superconductors. Resources The Electromagnetic Technology Division consists of three research groups: Optical Electronic Metrology, Cryoelectronic Metrology, and Superconductor and Magnetic Measurements. There are 99 total paid staff members, with 75 professionals (47 PhDs) and 18 guest researchers in the division. The total division funding is $12.6 million, with $8.5 million from congressional appropriations, $0.04 million from ATP funding, $0.084 million from calibration services, and $3.93 million from other sources. Electromagnetic Technology Division's Response to Fiscal Year 1992 Recommendations For the past several years, the panel has recommended that a Kerr-effect apparatus be set up (see the fiscal year 1992 assessment, p. 79). The division has finally hired a postdoctoral researcher who will build a scanning near-field Kerr microscope. The other relevant recommendation from the fiscal year 1992 assessment, i.e., to develop appropriate magnetic moment and coercivity standards for the recording industry, has not been considered because of a lack of staff. Panel's Findings, Conclusions, and Recommendations--Fiscal Year 1993 Division. Work quality continues to be high, and the balance among fundamental research, laboratory-based standards work, and generic technology research is about right for the Electromagnetic Technology Division. The division's involvement in NIST's ATP and in Cooperative Research and Development Agreements (CRADAs) will further sharpen its impact on new product development and U.S. industrial needs. The University of Colorado/NIST Joint Optical Electronics Institute 's approach of initially having four to six people from the university housed in NIST facilities and working on items of common interest should ensure early useful collaboration and results and maintain NIST control. The division's proposal for competence building funding in photonic packaging was denied, but a 1993 proposal for research on optical computing is now under consideration. Recommendation. The proposed optical computing research project should focus on the interconnecting and packaging of optics in computing rather than on digital logic. A project on
OCR for page 55
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 the metrological aspects of optical device fabrication or characterization of low-cost connectors would also be worthwhile and unique. Panel Comment on Division Strategy. The Electromagnetic Technology Division has selected optical computing for strategic emphasis. The panel questions the relevance of optical computing, because of lack of industrial interest. Cryoelectronic Metrology Group. The Cryoelectronic Metrology Group applies the unique properties of superconductors, particularly the Josephson effect, to the development of measurement techniques, devices, and standards of superior accuracy, sensitivity, and performance for fundamental metrology and for measurements of fast electrical waveforms and weak electromagnetic signals. An important part of the effort is the investigation of possible new fundamental quantum mechanical standards, e.g., the phenomenon of single electron counting as the basis for current and capacitance standards. The group is clearly the leader in the development and promulgation of the Josephson voltage standard and over the past year since the panel's 1992 assessment has positioned itself at the forefront in single electron counting metrology. In high-temperature superconducting electronics, the group is making world-leading thin-film technology contributions and is beginning to focus on high-critical-temperature applications. Progress in the competence building project in single electron counting research has been superb. Fabrication of devices with dimensions below 0.1 µm using e-beam lithography is in hand. Leading-edge experiments on noise and co-tunneling phenomena in Coulomb blockade devices have been completed. These experiments have provided substantial experience relevant to ultimately developing fundamental capacitance and current standards. A key noise issue, probably due to charge hopping between electronic traps in dielectric materials surrounding electrodes, has been identified and is now being studied. In the voltage standard area, the group's support of U.S. industry in adopting 1-V and 10-V standards has been steadfast. The long-standing supply shortage for voltage standard chips seems to be nearing resolution. There is now a commercial manufacturer for 1-V chips, which the NIST group buys, certifies, and then supplies (sells) to standards laboratories. The group is now getting good yield on the 10-V chips it fabricates. For the first time, there is a backlog of tested 10-V chips ready to ship to customers. These were fabricated by completing a key step, deposition of the insulator, at an industrial laboratory while upgraded equipment was being purchased and installed at NIST. Prospects for the 1-V chip commercial supplier also becoming the 10-V chip supplier seem reasonable. The intellectual focus in the voltage standards area has shifted appropriately toward developing a programmable standard
OCR for page 56
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 using a lower-frequency radio frequency source and a frequency multiplier based on single-flux quantum Josephson circuits. This project combines in an excellent way the group's expertise in the voltage standard and in digital Josephson design. The group's digital design expertise is also being used effectively to give vital circuit simulation and test support to the ATP and URI (a superconductor electronics project consortium consisting of the State University of New York at Stony Brook, the University of Rochester, and the University of California at Berkeley). Excellent progress is being made in developing an infrared radiometer standard based on the kinetic-inductance bolometer. A complete system, ready for delivery, offers about an order-of-magnitude better signal-to-noise ratio than the current radiometer standard, which is based on germanium resistance thermometers. However, at the request of the customer, delivery is being delayed so that a modification can be made to obtain a still-better performance. The Cryoelectronic Metrology Group clearly distinguished itself in fiscal year 1992 by fabricating a Josephson element with the highest achieved Josephson current-resistance product figure of merit yet, exceeding 1 mV at 77 K and 10 mV at 4.2 K. Progress was also made in realizing an improved microwave power-measuring standard, in microwave sources based on coherent Josephson oscillations, and in low-temperature superconducting quantum interference devices for a gravity-probe experiment. The current Cryoelectronic Metrology Group's competence building funding is due to terminate. Core funding and staffing are needed to continue the research. Recommendation. The Cryoelectronic Metrology Group should continue its current competence building project under core funding. A second permanent staff position should be added, and the two postdoctoral fellowships should be continued. The group should build on its accomplishments in the fabrication of high-temperature electronic devices by exploiting its advances in fabricating microwave Josephson junctions. Recommendation. The Cryoelectronic Metrology Group should emphasize demonstrations and applications of cryoelectronics designed for optimum performance at liquid-nitrogen temperature. However, because of staffing constraints, the group should probably set priorities for the use of the group 's unique talents. Superconductor and Magnetic Measurements Group. The Superconductor and Magnetic Measurements Group provides instruments, techniques, and standards advice for conductors used in large-scale superconducting magnets and to support the magnetics industry, with special emphasis on the recording industry.
OCR for page 57
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 The Superconductor and Magnetic Measurements Group is the preeminent source of instruments, techniques, and advice in the standards field for conductors used in large-scale superconducting magnets. The stewardship of the group's modest resources has been excellent, and it has generated OA funding to build the science base for standards work. Because new types of conductors are continually emerging in this rapidly changing field, industry needs a science base for current transfer at a superconductor-normal metal interface. Particular achievements of note are the development of ultralow impedance contacts, the round-robin testing of Nb3Sn conductors for fusion magnets, and the development of atomic-force microscopy to study pinning defects in high-temperature superconductors. The development of high-transition-temperature materials for conductors is still in its infancy, and new conductors are continually being developed. There are major opportunities to work closely with fledgling companies developing quality assurance protocols for these conductors. Each new material presents a special challenge because the optimum temperature range and the microstructures are different. Heat-transfer methods and protocols are needed in order to use magnets at temperatures where no liquid bath can be used. Refrigeration methods, heat-transfer techniques, and measurement protocols are needed for the full range of temperatures from 20 to 65 K. As noted in the fiscal year 1992 assessment, the space available for the research is very limited, and the group occupies space in several buildings. Recommendation. The atomic-force microscopy research should be located close to the magnetism and sample preparation facilities. The Superconductor and Magnetic Measurements Group has established a well-focused magnetic recording research program, especially considering the limited financial support for the effort. Research is currently under way in recording media and heads. The effort on scanned-probe microscopies is a good complement to this work. Double-layer magnetic films of relevant composition and structure are currently being fabricated and characterized. The data are in qualitative agreement with a micromagnetic model developed at NIST for the hysteretic behavior. Commercial interest in these films stems from their potential as low-noise recording media; therefore, a set of theoretical guidelines for producing the desired low-noise configuration would be of significant use to the recording industry. A second-generation microprobe station has been completed that is fully computer-controlled and now employs probes with tip diameters in the 0.1-µm range. The hard work of demonstrating the utility of this instrument to the recording community is about to begin. This instrument can be of considerable interest
OCR for page 58
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 to manufacturers of magnetoresistive heads, but a significant marketing effort will be required. Using its scanned-probe capability, NIST provided a disk drive manufacturer with data on surface roughness that will ultimately aid the company in increasing the storage density in its disk drives. Additional Comments. Although Japan has been chipping away at the market share, approximately 80 percent of the magnetic recording industry still belongs to U.S. manufacturers. This strong market share has been maintained by the research and development by U.S. companies. With the current upheaval at IBM and the cost-cutting measures at other information storage companies, industrial R&D in magnetics is being severely reduced. NIST can play an important role in maintaining superiority in the recording industry by using its measurement expertise for instrument development to supplement the reduced industrial effort. Because the trend in the recording industry is toward higher bit densities, it is possible to extrapolate to the measurement resolution that will be required over the next 1 or 2 decades. NIST should anticipate these future needs and be in a position to provide the necessary expertise when called upon. The scanned near-field Kerr microscope could become the major instrument in this area. Recommendation. The Superconductor and Magnetic Measurements Group should focus on quantitative measurements of stray magnetic fields arising from bit recording and magnetic recording heads. Furthermore, the group should acquire a spinstand, i.e., a magnetic recording system, that can record any desired bit pattern ranging from isolated bits to complicated patterns. Optical Electronic Metrology Group. The Optical Electronic Metrology Group, which emphasizes metrology to enhance U.S. industrial involvement in worldwide light-wave technology, is being made a separate division. It is appropriate that optics have a clear identity within EEEL. The photonics/light-wave industry continues to grow rapidly and is, increasingly, a key enabling technology for electronic systems. Some of the group's projects could now become groups with comparable budgets and technical depth. Other photonic, laser, and electro-optic projects (in EEEL and other parts of NIST) are candidates for inclusion in this new division. A review of the group's individual projects follows. Optical Fiber Measurement Systems and Practices. This project combines what were the group's two smallest projects in fiscal year 1992. Although this is one of the group's oldest
OCR for page 59
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 projects, significant new directions are being taken that will be valuable to industry. The work on fiber geometry responds to the optical fiber industry 's tighter requirements for simple and efficient splicing and connections. Coordination of an international round robin on geometry measurements is an appropriate undertaking of the division, as is the provision of a standard reference material fiber for geometry calibration. The project is beginning to work on connector ferrule geometry measurements. Precision measurement research for fibers and ferrules should continue to be coordinated within the relevant Telecommunications Industry Association fiber optics subcommittees in which U.S. industry actively participates. With higher bit rates and signal bandwidths, and as fiber amplifiers are extending fiber lengths between terminals or repeaters, fiber chromatic dispersion has gained renewed importance. An earlier round robin on fiber chromatic dispersion sponsored by the group demonstrated a measurement accuracy that by now may be inadequate. The project 's research on highly accurate measurements will be most helpful in addressing these new applications. Optical time-domain reflectometry is useful for practical factory and field measurements, since it yields performance of the fiber along its length. Development of a fiber-optic delay line by the project, utilizing unique capabilities in low-coherence reflectometry, will increase the precision of length measurements necessary for accurately locating features at particular distances, such as faults that may need repair. Concerning its high-resolution optical time-domain reflectometry, the Optical Electronic Metrology Group has new concepts that should improve commercially available instrumentation. The group has expertise in low-coherence reflectometry, saturable absorbers, and microchip lasers that can be directed toward this goal. Multiwavelength lasers are of increasing interest for spectral characterization by optical time-domain reflectometers, especially for factory application. The proposed reexamination of low-resolution measurements as the result of long intervening distances is appropriate. A related topic, transmission uniformity as a function of length, is of increasing interest to the standardizing community. The group's staff could lend expertise to Telecommunications Industry Association Fiber Optics committee discussions. Attributes such as the length dependence of the attenuation coefficient, mode field diameter, cutoff wavelength, and perhaps dispersion can be probed with an optical time-domain reflectometer, but the procedures are not well developed. A topic not specifically being addressed by the group, either in this project or in the Characterization of Sources and Detectors project, is optical-fiber amplifiers. In particular, the erbium-doped fiber amplifier is now the subject of standardization activities, and some of the measurement procedures are controversial. Unfortunately, these standards are
OCR for page 60
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 not being issued first in the United States, but rather internationally by the International Telecommunications Union (formerly the Consultative Committee on International Telegraphy and Telephony) and by the International Electrotechnical Commission. However, the United States is contributing, and this group, in view of its experience in this area, would be a welcome participant in reviewing and generating documents. Recommendation. Representatives of the Optical Electronic Metrology Group should participate in Telecommunications Industry Association Fiber Optics committee work on setting branching component measurement standards. Laser Power and Energy Measurements. This project is responsive to industry's calorimetry needs. Much of the project's response is of a service nature. The project's round-robin measurements in laser beam profilers and in optical-fiber power meters are especially noteworthy. The project seems well connected to standards activities both in the United States and abroad. Recommendation. The Laser Power and Energy Measurements project's activities in the definition of parameters to characterize non-Gaussian laser beam profiles should continue, and efforts in the optical-fiber power meter area should continue to investigate issues associated with reflections from fiber connectors. The transmittance measurements on samples of laser-safety eye wear are also significant. It is important that the excimer calorimetry system and the Nd:YAG laser calibration system come on-line as expeditiously as possible, to be responsive to industry requests. Characterization of Sources and Detectors Project. Efforts in this project are somewhat varied, and several deserve special mention. The work in wavelength standards at 1.3 and 1.55 µm is becoming important for industry as tunable lasers and optical spectrum analyzers are further developed and as telecommunications move toward dense wavelength-division multiplexing in the erbium-doped fiber amplifier passband. Future systems will probably have channels spaced equally in frequency rather than in wavelength. The project 's new CRADA in this area is significant. Portable gas cells for intermediate accuracy standards seem practical, and the high-resolution standards formed by cooling and probing rubidium appear very promising. This latter effort has also incorporated pertinent work into tunable fiber lasers and fiber Bragg gratings. The heterodyne system for characterizing detectors to 30 GHz and the plans to extend this range to 120 GHz are unique. This work is of high quality and relevance, as is the project's continuing research in flat-response and pyroelectric detectors. The project's new activity in laser diode relative-intensity noise measurement and its relation to standards activities are
OCR for page 61
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 especially important. The research should be extended to fiber-coupled, diode-pumped solid-state lasers as well, because of their use in cable television and other analog fiber-optic signal transmissions. Activities in picosecond electro-optic sampling are relatively mature, but it appears that industry is not yet ready to fully embrace this measurement technique for new commercial instruments. Industrial interests should continue to be monitored. An alternate approach using low-coherence techniques should continue to be explored, since this is another method for some measurement needs addressed by short-pulse techniques. In general, the Characterization of Sources and Detectors project could be better coupled to the expanding U.S. standards activities, a step that would affect the selection of new research topics and specific activities of the staff. Integrated Optoelectronics. This project is concerned with the fabrication and characterization of both in-plane guided-wave devices and vertically oriented photonic devices. Activities include theoretical and experimental work. Bringing the chemical-beam epitaxy system on-line in fiscal year 1992 was a major milestone. Initially, this system is being operated in a molecular beam epitaxy mode with evaporative sources, and it has already produced high-quality multilayer mirrors of the type used in vertical cavity surface emitting lasers. The significant value of the machine will be in developing in situ growth diagnostic measurements and in growing phosphorus-based multiple heteroepitaxial structures for 1.3- and 1.55-µm wavelength applications. In response to the panel's fiscal year 1992 assessment, a major effort has been made to concentrate on measurement techniques for the multilayer films used for vertical cavity surface emitting lasers. These have been studied to gain understanding in using relatively simple techniques to obtain accurate dimensional and compositional data without requiring time-consuming and destructive transmission electron microscope measurements. Collaboration with local industry has already begun. The panel endorses the development of chemical beam epitaxy growth technology for fabrication of materials and devices relevant to the measurement techniques, standards, calibration services, and reference data for lasers, detectors, and fiber-optic metrology missions of the division and EEEL. In guided-wave optics, the project's measurement and modeling of amplifiers and lasers have attracted significant industrial interest. There are a number of materials issues to be resolved before the devices can become practical, and part of the challenge is to determine appropriate measurement techniques to characterize the optical and spectroscopic properties of materials and devices to ensure an understanding of device development issues. One study focused on glass guided-wave amplifiers for 1.3-µm applications. This important area has not
OCR for page 62
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 been effectively addressed by fiber devices due to fiber material issues. Recommendation. Specially grown glasses have produced promising results, and a significant level of effort should continue. The lasing properties of these glass guides should be investigated, with a significant focus on understanding the implications for amplifiers and addressing material and measurement issues. In LiTaO3, there is the promise of guided-wave red-blue-green sources formed by intracavity on-chip doubling and up-conversion techniques. Results to date are very encouraging. A significant issue is again materials, since the properties of LiTaO3 vary significantly between boules and even among wafers from the same boule. Recommendation. Because of the potential importance of LiTaO3 devices, the Optoelectronics Metrology Group should collaborate with integrated optic manufacturers, users, and material suppliers to develop characterization methods to qualify and improve wafers. As a result of the embryonic state of guided-wave devices, the group has a good opportunity to be involved in the development of the technology from the beginning. Optical-Fiber Sensors. This project continues to provide optical-fiber sensor techniques with enhanced performance over competing techniques. It also fabricates measurement devices, e.g., the YIG-based current sensor, magnetic field detectors that lower the detectable field by magnetic flux concentration, and a precision quarter-wave retarder. The project has considerable expertise in measurements of high-birefringence fiber and components. Some potential measurement topics of the Optical-Fiber Sensors project overlap those of the project for Optical Fiber Measurement Systems and Standards. A decision will be necessary on where to place these projects when the Optical Electronic Metrology Group becomes a division. Polarization measurements on low-birefringence fiber and components for communications are important for high-bit-rate/high-bandwidth long-distance systems, and for future coherent systems. Polarization-mode dispersion in fiber can compete with chromatic dispersion and may affect the accuracy of measuring the latter. In passive components, such as connectors and splitter couplers, polarization-mode dispersion is small, but polarization-dependent loss may be significant. U.S. standards activity in the above areas has just begun, and the group has rare expertise to contribute. Research on optical branching components straddles several of the Optical Electronic Metrology Group's projects. Sensors utilize optical couplers and are of increasing use in test equipment and in communications. An example is passive
OCR for page 63
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 (nonelectronic) point-to-multipoint signal distribution, possibly with wavelength-division multiplexers. The Optical-Fiber Sensors project continues to develop superior optical-fiber sensor techniques. Project funding still comes primarily from outside resources. Recommendation. To examine sensors beyond those that are intensity-based, such as frequency-based sensors, expand the new approach to remote self-calibrating systems. Supplement outside funding with more internal funding directed toward some new sensor applications such as distributed, environmental, or chemical sensing. Also, strengthen theoretical work to provide new impetus to experimental ideas.
OCR for page 64
An Assessment of the NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY PROGRAMS: Fiscal Year 1993 This page in the original is blank.
Representative terms from entire chapter: