Communications
Widely-Tunable Cascade Laser for Tree Space Optical Communications
PI: G. Belenky
The proposed design of 3.2 mm semiconductor laser for optical communication links offers electrical tuning of the emission wavelength with the fastest response. This makes it possible to employ frequency modulation in the laser-based free space communication systems for improved signal-noise ratio and extended range. This principle was proven to be effective in the microwave frequency range while in the optical range it was never employed. (ARO)
Design Automation for Complex Analog and Mixed-Signal Systems Used in Wireless Communication
PI: Alex Doboli
Existing CAD techniques are largely insufficient for designing modern analog and mixed-signal (AMS) systems. They do not achieve optimality since they consider only a limited number of design options. Synthesis tools are difficult to use (as they require significant designer input), are slow, and experience numerous convergence difficulties. To address the enumerated challenges, our primary research goal is developing automated methodologies and methods that can handle large systems of various types, offer fast design closure, and are easy to use. The main aspect of our work is a holistic approach to AMS system synthesis. We are co-developing methods for
1) AMS topology synthesis,
2) topology mapping,
3) constraint transformation, and
4) circuit modeling for synthesis.
Our work is based on three main innovations that transcend the four tasks:
1) Generic topology representations (GTR) are comprehensive and consistent descriptions of the design space for topology synthesis, topology mapping, and constraint transformation. GTR allow automatically finding optimal topologies, and can be related to circuit nonidealities.
2) Successive refinement finds constraint-satisfying solutions by gradually eliminating poor design space regions, and not by explicitly searching for good points, as in present heuristics. Successive refinement incorporates pruning strategies specific to the nature of the design space and circuit models.
3) Bottom-up transformation based modeling automatically creates structural models for analog circuits. Models may be linked to generic topology representations, thus offering an easy yet accurate way of modeling new topologies.
The research is expected to advance the state-of-the-art in system synthesis for complex AMS systems, and offer a complete AMS system synthesis flow. The flow will reduce design cost and time (DARPA, CDADIC).
2.3-mm Diode Laser Arrays
PI: D. Donetski
The project is aimed at development of light emitters operating in the 2.0-2.4 mm atmospheric transparency window for secure free space optical communications and ultra-sensitive remote gas monitoring as well as for pumping semiconductor lasers operating in the 3 - 5 mm transparency window. Compared to other wavelength ranges, these windows have the lowest background noise from both scattered solar radiation and thermal emission of Earth while the corresponding detectors do not require cryogenic cooling to achieve the required noise performance.
Semiconductor diode lasers offer the potential of high-power light source with the advantages of superior conversion efficiency, simplicity of electrical modulation, compact hardware design and low cost. The laser design developed in SUNY demonstrates the lowest threshold current and the world-record continuous wave output power. (Power Photonic Corp.)
Semiconductor Electronic Sources for the Terahertz Region
PIs: R. Kamoua, H. Eisele
The objective of this activity is to design and investigate the potential of InP Gunn oscillators for second and third harmonic power generation at frequencies above 200 GHz. The goal is to provide powerful, low-noise, compact, and efficient local oscillators for receiver systems. Theoretical and experimental work has demonstrated that these devices can generate RF power up to 325 GHz in the second harmonic mode. This clearly indicates that the potential and capabilities of InP Gunn devices were underestimated in the past and that RF sources with these devices can generate sufficient RF power levels up to the lower submillimeter-wave frequencies. Therefore, these devices may help eliminate one or two stages in a multiplier chain to reach terahertz frequencies. These findings have applications in medical imaging, environmental monitoring, chemical spectroscopy, high-resolution radars, and ultra-wide bandwidth communications. This work will consider the potential of third harmonic power generation to reach higher frequencies in the terahertz region. (NSF)
Wavelength-Division-Multiplexing (WDM) Optical Interconnects for Parallel and Distributed Computing and Communications
PI: Yuanyuan Yang
Optical communication, in particular, wavelength-division multiplexing (WDM) technique, has become a promising networking choice to meet ever-increasing demands on bandwidth from many emerging bandwidth-intensive computing/communication applications. As optics become a major networking media, optical interconnects will inevitably play an important role in interconnecting processors in parallel/distributed computing systems.
This research focuses on fundamental challenges and issues on using optics in two converging areas: parallel/distributed computing and communications. The objective of this research is to design high-speed, cost-effective optical interconnects for current and future generation parallel/distributed computing and communication systems. Due to the unique characteristics of optics, many important issues of optical interconnects, different from those of electronic interconnects, need to be addressed. This research focuses on the following tasks: exploring unique properties and classifications of WDM interconnects, optimal and cost-effective designs, studying the effect of wavelength conversion, performance modeling and packet scheduling algorithms. Our research have generated viable solutions for designing high-bandwidth, high-connectivity, low-latency and low-cost optical interconnects for next generation parallel/distributed computing and communication systems. (NSF)
Multicast Communication in Switch-Based Networks
PI: Yuanyuan Yang
Multicast communication involves transmitting information from a single source to multiple destinations, and is a requirement in high-speed, high-performance networks. Current trends in networking applications indicate an increasing demand in future networks for multicast capability. Many multicast applications require not only multicast capability but also predictable communication performance, such as guaranteed multicast latency and bandwidth. This research designs a QoS capable multicast architecture based on the multicast switches with some built-in QoS functions to support arbitrary multicast communication with varying QoS requirements. Specially, the research comprises four fundamental components: (1) design basic building block multicast switches with better QoS functions and lower network cost than those existing ones; (2) establish analytical models for the important performance metrics of multicast communication in the design of statistical QoS capable multicast architectures, such as communication latency, blocking probability, network throughput, reliability and fault-tolerant capability under different types of input traffic and routing algorithms; (3) study efficient multicast packet scheduling algorithms for different QoS requirements; (4) build a QoS capable multicast architecture for scalable and high performance parallel and distributed computing systems. (NSF, ARO)