Tag Archives: performance

Low-Power, High-Performance Tunneling Field Effect Transistors for Advanced Computing

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Summary:

Silicon-based field effect transistor (FET) devices are building blocks of silicon-based digital, analog, and hybrid electronics. Often made of a metal-oxide-silicon (MOS) type structure, these devices are interconnected to generate so-called "complementary" MOSFET circuits, known as CMOS transistor circuitry. CMOS enjoys the benefits of low power and high speed operation, and advancements in these two properties have primarily been achieved through reduction of the channel length, which is now well into the submicron range for commercial devices. However, CMOS technology is approaching certain fundamental limits that will prohibit further miniaturization, likely due to the complex material formulations used. To overcome these limits, researchers at The Ohio State University have developed a novel Tunneling Field Effect Transistor (TFET) that will allow for further device miniaturization, reduced power, and increased speed beyond what is possible with current CMOS technology, while still enabling the use of well-established CMOS manufacturing processes.

Potential Applications:

  • High-performance computing
  • Power-constrained military systems
  • Handheld/miniature electronics
  • Practically anywhere silicon-based electronics are used

Advantages:

  • Extends CMOS, enabling a new generation of device topologies while allowing the use of current manufacturing processes
  • Faster turn-on at lower voltages than competing TFET designs
  • Steep sub-threshold slopes (below 60mV/decade)
  • Less current leakage in the "off" state compared to competing TFET designs
  • Higher current densities in the "on" state compared to competing TFET designs

Instantaneous Monitoring of the Quality of Optical Telecommunications Links

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Summary:

Ohio State researchers have developed a novel method of signal quality monitoring that can reliably assess the quality of a digital signal in as little as 100 picoseconds, thousands of times faster than traditional bit-error rate (BER) or eye diagram testing. The technique compares bit shapes in an all-optical system to detect the combined effects of attenuation, dispersion, noise, and timing jitter. The hardware is simple, compact, and far less expensive than traditional QoS systems. This system allows users of optical links to quickly and accurately assess their data quality. Using this information, more intelligent networks can be designed and implemented.

Potential Applications:

  • Optical performance monitoring
  • Optical routing and switching
  • Digital communication systems (electronic or optical)

Advantages:

  • Compact, simple, inexpensive hardware
  • Orders of magnitude faster than traditional electronic bit error rate measurement
  • Instantaneous monitoring of optical link quality

Advanced High-Efficiency Nanowire LEDs

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Summary:

There is great interest in developing new solid state semiconductor-based light emitting diodes (LEDs) that exhibit new functionality and performance. Principal challenges in creating new semiconductor LED structures include the formation of defects and low doping efficiency, both of which negatively affect device performance. To overcome these challenges, researchers at The Ohio State University have developed new methods and device structures that lead to defect-free, high-efficiency nanowire LEDs. These LEDs can be easily mass manufactured and integrated in silicon electronics, and can hit any bandgap due to the lack of strain relaxation.

Potential Applications:

  • Lighting
  • Laser diodes
  • Photodetectors
  • Communications
  • Sensors

Advantages:

  • Defect-free formation during epitaxial growth
  • Extremely high-efficiency
  • Low resistance
  • Enables simple and broad bandgap engineering
  • Low manufacturing costs and easy integration into Si electronics

Device and Method for Producing Optically-Controlled Incremental Time Delays

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Summary:

Generating precise and reliable true time delays (TTDs) is of paramount importance for phased array radars and a host of other applications. True time delay avoids beam squint in wideband antenna systems. Researchers at The Ohio State University have developed a free-space optical TTD device that can provide many bits of delay (more than 15 bits) for hundreds of antenna elements in ultra-compact form (half a cubic foot) with delays varying from femtoseconds to tens of nanoseconds. The invention uses a single MEMS chip, free space for massive overlapping of beam space, and a handful of mirrors. A programmable tapped delay line has many other uses, including optical correlation, optical matched filtering, optical signal processing, optical code-division multiple access coding and decoding, photonic analog-to-digital conversion, and optical communications performance monitoring. A variation of the device can also be used for optical interconnections and routers. Electronically implementing TTDs is generally impractical because of the need for many long lengths of strip line, waveguides, or coaxial cable, which are expensive, bulky, and temperature sensitive. Since long path lengths are relatively easy to obtain optically, optical TTD systems have been developed, either using fibers or free-space paths, but these existing systems are expensive and bulky due to the use of multiple optical switches. Researchers at The Ohio State University have developed a free-space optical TTD device that uses only one optical switch or spatial light modulator for the entire system instead of one or more switches for each bit, as in previous systems. Furthermore, the device avoids beam-spreading problems that may be present in other free-space systems by using a multiple-pass optical cell with refocusing mirrors. As a result, the device is more inexpensive, compact, and temperature insensitive than existing devices.

Potential Applications:

  • Optical multiplexing/demultiplexing applications
  • Optical routing and switching
  • Phased array radars
  • Optical signal processing
  • Optical performance monitoring

Advantages:

  • Uses only one optical switch or spatial light modulator
  • Ultra-compact form factor
  • Small component count