The Department of Electrical and Computer Engineering at West Virginia University began its own curriculum revision process in 1993 influenced by these same factors. The department is in a transitional phase reflecting formation of a new accredited program in Computer Engineering (CpE) and new emphasis in advanced system technologies and packaging, computer architectures, signal processing, and communications brought about through five new faculty members which have joined the department since 1990. Two of the five new faculty members brought with them over 30 years of combined corporate research and development experience at AT\&T Bell Laboratories and a commitment (expressed through recent formation of the Microelectronic Systems Research Center (MSRC)) to developing educational excellence through coupling of research and instructional efforts. While mirroring national trends, the departmental realignment and curriculum review currently underway reflects a shift in the regional economy away from natural resource intensive industries (coal, lumber, power) towards a technology orientation represented by local DOE and NIOSH facilities, and new NASA and FBI data centers supported by a recently completed statewide fiber optic network infrastructure. Efforts at WVU to improve ECE facilities and curriculum are motivated by the recognition that modifications of the ``traditional'' educational approaches presently in place are required both for preparation of students for the new engineering workplace emerging from this regional (and global) industry shift and to better stimulate growth in the fraction of students choosing to continue with graduate studies.
As a land grant institution, West Virginia University draws approximately 65-70% of its 22,000 students from West Virginia. This statistic is closely mirrored within ECE where among the yearly undergraduate class enrollments of from 65-75 students approximately 10% are female, 10\% are of other minorities and less than 5% are foriegn nationals. Many of the students in ECE are first generation college students and of the approximately 80% of undergraduate students who begin careers after graduation, most WV natives seek employment in this transforming regional economy.
Both the complexity and need for integrated understanding of course work material across the curriculum increases dramatically during the junior year as students are introduced to the fundamental fields of electrical engineering through in depth courses such as signals, systems, circuits, solid state electronics, and electromagnetics. Rather than kindling enthusiasm in students for the opportunities in electrical engineering for creation of new and varied applications through a coupling of topics from their courses, students often see this as a fracturing of their knowledge and efforts unless the synergy of the topics is explicitely explored through application of course concepts to a common, contemporary system-level application. While WVU has a strong tradition of senior design projects (see below), the curriculum integration achieved is often too late in students' undergraduate careers to meaningfully impact their attitudes towards and awareness of their fundamental course work. The Communication System Prototyping Laboratory (CSPL) seeks to provide a laboratory resource for integration of junior and senior level required and elective topics through communication based applications.
In order to evoke a natural enthusiasm and appreciation in students for the power of their knowledge and kindle their desire for advanced studies, the proposed Communication System Prototyping Laboratory (CSPL) seeks to establish a similarly rich environment in an instructional laboratory setting through use of multiple microlabs within a single instructional lab physically linked via a prototype network. As diagrammed in Figure 1, each microlab consists of a work area with equipment, components, and documentation supporting design and prototyping for a specific system-level technology application (e.g. lightwave, voice/audio, video, etc.). A spool-based optical fiber network, supported by the Lightwave Microlab, serves as the transmission backbone of the CSPL. A lightwave network was chosen as the educational communication testbed due to the important range of photonic applications opened to students, the ease of implementation within an undergraduate instructional lab context ( e.g. relative to microwave or wireless/radio), the strong relevance to state and national economic emphasis on information technology, and the natural affinity exhibited by students towards lasers and optoelectronics.
Figure 1: Organization of the Communication Systems Prototyping Laboratory based upon an application driven coupling of discipline specific ``microlabs'' with an optical communication network backbone. A transmission path for an audio application is shown.
The economy of providing a single microlab servicing a particular field within a larger laboratory framework enables crucial representation of transmission system technologies such as lightwave (or e.g. microwave, wireless/radio) requiring high-end equipment which would otherwise be prohibitively expensive in a conventional (multiple redundant work area) laboratory format. In addition, new microlabs can be readily added as interesting new applications emerge, allowing the overall lab to be built up through successive class laboratory projects. The modularity of the CSPL makes its organization general to any EE department seeking curriculum integration through laboratory design experiences while promoting custom tailoring of the microlabs to the required and elective course needs of a specific curriculum.
Linkage of the microlabs, physically with the fiber network and conceptually with the communication application, is at the heart of the CSPL concept. The modular, yet interdependent, ``networked'' nature of the CSPL's interconnected microlabs enables the lab to serve as a curriculum wide resource supporting both junior and senior level required courses and advanced elective courses. Individual course lectures and laboratories will tap specific microlab resources to broaden and give an application emphasis to lecture demonstrations and lab design projects. However, it is use of an overarching communication application within the context of these individual lab and lecture experiences which provides students with an exciting system environment that draws them into exploration of the system-level impact of their design decisions and discovery of the crucial role their fundamental EE course backgrounds play in the design process.
Figure 2: Implementation of the CSPL Lightwave Microlab
within the Microelectronic System Prototyping Laboratory (MSPL).
Analog Electronics, EE~158/159 (Spring 3 Cr. lecture, 1 Cr. lab, 60-70 Students) The lab excercises of this transister circuit analysis course typically involve design of low frequency amplifiers of specified gains but draw only upon the students electronics course background. Figure 3(a) shows one example of a CSPL design experience using the lightwave and audio microlabs which draws upon nearly all junior courses while still demonstating students' individual analog electronics knowledge. Through the process of designing and implementing the analog optical communication channel shown, student groups design an audio frequency amplifier LED/LD driver combination and a photodetector receiver/speaker driver. In this design process students necessarily must take into account the fiber transmission path and optoelectronic device coupling losses (which can be quantitatively measured using lightwave microlab equipment) in order to design their circuits. Changes in loss can immediately be audibly detected as well as quantitatively measured. Basic optics and optical engineering principles are also developed through the optoelectronic device/fiber alignment process which each group will undertake in connecting to the fiber spool testbed.
Figure 3: Representative analog (a) and digital (b)
communication design projects.
Microprocessors, CpE~110/111 (Fall 3 Cr.course and 1 Cr.lab, 60-70 students) This course explores the 68000 microprocessor architecture and uses a single board 68000 computer for student designs. One project currently done which is readily extendable to the Lightwave Microlab is recording, manipulation, and replay of speech using the board's A/D and memory. As shown in Figure 3(b), using TTL I/O optical transcievers, students can design simple fiber interfaces and protocols to transfer the voice data between boards across the fiber network.
Signals and Systems, EE~124/125,126/127 (Fall \& Spring, 3 Cr.course and 1 Cr. lab each, 60-70 students) This course provides the students with the continuous and discrete systems analysis foundation for understanding of communications fundamentals. Transfer functions and frequency response principles can be extended to transmission media by having students examine both the optical frequency response and temporal response of different optical fiber channels (e.g. single mode vs. multimode) and compare this to lower bandwidth electronic media such as twisted pair. Drawing again upon the audio link described above, the concept of carrier modulation can be examined and the impact of channel characteristics at the carrier frequency illustrated. Optoelectronic diode nonlinearity can be exagerated (e.g. with improper bias point) and their effect shown via audio microlab spectrum analyzers.
Electric and Magnetic Fields II,EE~141 (Spring, 50-60 students) this lecture course draws upon field and wave visualization software (NSF/IEEE CAEME) and lecture demonstrations to provide students with an understanding of the fundamentals of electromagnetic wave propagation in different media but, as at most schools, suffers from the inability to realistically (both in cost and student/faculty time) offer a course lab. Through an infusion of electromagentic principles into the communication based design experiences in the existing labs of other courses such as described above, students will be drawn into applying and developing their electromagnetics background substantially beyond that obtainable through lecture material and homework. Students will be motivated further through direct optical communication based lecture demonstrations of principles and measurements they will use to successfully complete their lab designs in these courses. These include reflective power loss, propagation delay, OTDR, optical filters, narrow band vs. broad band antireflection coatings, and media wavelength dependent absorption.
Electronic Properties of Materials/Semiconductor Devices, EE~151 (Fall, yearly, 50-60 students) This lecture course has recently been expanded to include basic optical detector, LED, and laser diode devices. As with the electromagnetics course, device principles (optical detection, source spectra and receiver responsivity, device optical output distributions, etc.) will be demonstrated in lecture using portable lightwave microlab equipment. Through the communication based projects of other course labs, students will by necessity need to use and integrate with electromagnetics, circuits, and systems understanding, the device principles developed in class lectures and demonstrations.
Senior Design Seminar/Project, EE/CpE~180, 181 (Fall \& Spring, 60-70 students) A strong capstone design program for seniors has been established within the EE/CpE 180 course, followed by the 181 course in which the design is converted to a real system. In this sequence, small groups of students select and develop a detailed proposal for a project to be completed during the senior year. While the number of senior projects with an optoelectronic, photonic, and communication basis have grown significantly, the students' lack of prior hands-on prototyping skills in these areas requires them to spend significant time developing this experience, thereby lowering the final technical level achieved. Also, temporary loan of equipment and hardware from research labs has become inadequate to fulfill this growing undergraduate student demand. The CSPL Lightwave Microlab not only broadens the range of potential projects but more importantly the student knowledge base built through the communication applications used in their course labs increases the technical level of the projects which the student can undertake.
Optical Communications, EE~248 ( Fall, yearly,25-30 students.) This lecture course has the highest enrollment of any senior elective and will dramatically benefit from the CSPL Lightwave Microlab resources as well as from the exposure students will already have received to the topic through their other course laboratories. Students can look experimentally at the full set of individual issues effecting the optical communication link (e.g. optical input/output coupling and wavelength dependent transmission loss, dispersion, noise margin, etc.) and their impact on bit error rate as indicated both with a quantitative BER value and eye diagram analysis. Student projects can build upon their previous lab experiences and extend to such areas as Wavelength Division Multiplexing (WDM) as illustrated in Figure 4. Here the impact of spectral purity of sources can be readily shown using LED verses laser diode sources and seeing the impact on individual channel quality (analog/audio) or BER (digital).
Figure 4: A communication course two channel WDM optical
link project.
Introduction to Communication Systems, EE~264 (Fall, yearly, 10-15 students.) This class provides students with background in classical communication theory as well as current transmission standards and techniques. A number of the lab design experiences already sited can be further extended for this class. Also, with the local national FBI fingerprint center and NASA EOS center, image compression and transmission is especially relevant. The Lightwave Microlab could support a range of image transmission projects in which students implement software JPEG compression and decompression code for image transmission over the fiber link using the PCs in the MSPL and the microprocessor/digital optical link such as diagramed in Figure~\ref{analog}(b). Of specific interest is the robustness of the JPEG decompression for high bit error rate channels (e.g. large dispersion and high loss/low launch power).
VLSI Microfabrication Technology, EE 291 (Fall, 15-20 students.) This course treats microfabrication technology as a foundation technology for electrical, optical, and micromechanical devices. A basic microfabrication lab assembled through AT\&T, IBM and Union Carbide donations enables student fabrication projects. Simple yet illustrative of fundamental fabrication limits, integrated optical components (waveguides, splitters, fresnel lenses/diffractive optics for fiber and component coupling) will be introduced as course fabrication projects. Lightwave Microlab resources will enable characterization of these components. Successfully fabricated passive optical devices will become part of the Lightwave Microlab extending its resources and seeding student interest in this elective.
Fundamentals of Photonics, EE~291 ( Spring, yearly, 20-25 students.) This newly inaugurated course includes treatment of matrix geometric optics, wave optics, optical resonators, fourier optics, acousto-optics, optical processing and advanced optical devices. The CSPL Lightwave Microlab provides a substantial equipment and hardware base from which projects and class demonstrations can be crafted. For example, with its bulk optical components and optomechanical hardware, students can design and explore optical fourier transforms and build basic 4f optical signal processors. Illustration of such important concepts as cavity mode spectral properties using both laser diodes as well as student constructed Fabry-Perot resonators will be also be possible.
Fiber Spool Network: A 1 km length of multimode fiber (4 to 10 dB/km) and a 1~km length of single mode fiber (1 to 3.5 dB/km) are budgeted. A mode scrambler is also included as part of the prototype network functional unit. A total of three {\em network interface units} (NIU) are requested to provide connectorized yet flexible interface to the network. Each is composed of an optical breadboard with two GRIN lens fiber couplers for coupling from the users FC patch cord to the unjacketed network fiber. Two NIUs are used at the network input and output while the third provides collimated fiber I/O at the fiber spool protoyping tap.
Photonic Prototyping Center:~} Funding for six {\em photonic protoboard units (PPUs) is requested to provide students with a flexible connectorized interface to the network interface units discussed above and illustrated in Figure 3. Each PPU has a basic TO can laser, device translation stage and a GRIN fiber coupler to launch optical power into an attached FC fiber patch cord. With these units, students can optimize fiber coupling with a simple detector or power meter prior to connecting their patch cord to the network. Funding is also sought for a finderscope to aid in IR alignment. For direct digitally interfaced experiments, two 155~Mb/sec optical data link transciever pairs are requested. To enable true hands-on student photonic prototyping through customization of PPUs, fiber tap experiments, as well as specialized course projects (see above), support is also sought for purchase of a basic optomechanical hardware set, optics set, and lens set. Two Uniphase HeNe lasers previously donated by AT&T provide DC optical sources for optical system prototyping in conjunction with a fiber power meter and calibrated laser diode fiber source for which funding is requested.
Lightwave Test & Measurement Center: The requested Tektronix CSA404 Communication Signal Analyzer with the two calibrated optical/electrical converters and input amplifiers covers the full lightwave source spectrum and enables all time domain communication measurements including signal, jitter, noise margin, eye diagram mask/BER and attenuation. When coupled with the Tek OIG501 optical impulse generator, full OTDR and calibrated reflection analysis can be achieved. The Advantest Q8344A Optical Spectrum Analyzer enables full frequency analysis in the optical domain for device, transmission medium (a white light source is already available for broadband fiber excitation), and WDM channel measurements.
The second co-PI, Professor Das, joined the Department of Electrical and Computer Engineering at West Virginia University in August 1994 from the University of Notre Dame. Adding to his strong research background in nanoelectronics and optoelectronics Das also holds a strong commitment to improvement of undergraduate electrical engineering education as illustrated by his ILI-IG and ILI-LLD award which he received while at Notre Dame.