Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High-Speed Signal Mixer Demonstrates Capabilities Of Transistor Laser

20.03.2009
Scientists at the University of Illinois have successfully demonstrated a microwave signal mixer made from a tunnel-junction transistor laser.

Development of the device brings researchers a big step closer to higher speed electronics and higher performance electrical and optical integrated circuits.

The mixing device accepts two electrical inputs and produces an optical signal that was measured at frequencies of up to 22.7 gigahertz. The frequency range was limited by the bandwidth of the detector employed in the measurements, not by the transistor device.“

"In addition to the usual current-modulation capability, the tunnel junction provides an enhanced means for voltage-controlled modulation of the photon output of the transistor laser,” said Nick Holonyak Jr., a John Bardeen Chair Professor of Electrical and Computer Engineering and Physics at the U. of I. “This offers new capabilities and a much greater sensitivity for unique signal-mixing and signal-processing applications.”

To make the device, the researchers first placed a quantum well inside the base region of a transistor laser. Then they created a tunnel junction within the collector region. They describe the fabrication and operation of the mixing device in the March 13 issue of the journal Applied Physics Letters.

“Within the transistor laser, the tunneling process occurs predominantly through a process called photon-assisted absorption,” said Milton Feng, the Holonyak Chair Professor of Electrical and Computer Engineering.

The tunneling process begins in the quantum well, where electrons and holes combine and generate photons, Feng said. Those photons are then reabsorbed to create new pairs of electrons and holes used for voltage modulation.

“The tunnel junction makes it possible to annihilate an electron in the quantum well, and then tunnel an electron out to the collector by the tunnel contact,” Feng said.

The transistor output is sensitive to third-terminal voltage control because of the electrons tunneling from the base to the collector, which also creates an efficient supply of holes to the quantum well for recombination.

“This is a new type of transistor,” said Holonyak, who also is a professor in the university’s Center for Advanced Study, one of the highest forms of campus recognition. “We are using the photon internally to modify the electrical operation and make the transistor itself a different device with additional properties.”

High-speed signal mixing, for example, is made possible by the nonlinear coupling of the internal optical field to the base electron-hole recombination, minority carrier emitter-to-collector transport, and the base-to-collector electron tunneling at the collector junction, the researchers report.

The sensitivity of the tunnel-junction transistor laser to voltage control enables the device to be directly modulated by both current and voltage. This flexibility facilitates the design of new nonlinear signal processing devices for improved optical power output.

“The metamorphosis of the transistor is not yet complete,” Holonyak said. “We’re still working on it, and the transistor is still changing.”

Co-authors of the paper are graduate research assistant and lead author Han Wui Then, graduate student Hsin-Yu Wu and senior research scientist Gabriel Walter.

James E. Kloeppel | University of Illinois
Further information:
http://www.illinois.edu

More articles from Physics and Astronomy:

nachricht Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences

nachricht Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication
16.07.2018 | Chinese Academy of Sciences Headquarters

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Subaru Telescope helps pinpoint origin of ultra-high energy neutrino

16.07.2018 | Physics and Astronomy

Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides

16.07.2018 | Life Sciences

New research calculates capacity of North American forests to sequester carbon

16.07.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>