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The Transistor Laser

Ultrafast transistors that output optical and electrical signals open new computing frontier

12 min read

For years we've been hearing about all the fantastic things computers will be able to do once they process data with light instead of electricity. The mysteries of the universe will be unlocked. A golden age of limitless computing power and bandwidth will usher in a techno-utopia.Don't believe the hype.

Setting aside the question of whether an all-optical processor would even be desirable, optical computing schemes lack the photonic equivalent of the most fundamental computing element, the transistor. That device--first demonstrated in 1947, when John Bardeen and Walter H. Brattain stuck two cat-whisker wires onto a germanium base and showed power gain from one wire, called the emitter, to the other, called the collector--spawned the US $300-billion-per-year semiconductor industry. The transistor makes possible our digital lifestyle: cellphones and PCs, digital cameras and MP3 players, medical imaging systems and set-top boxes, supercomputers and the Internet, and more.

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The Future of Deep Learning Is Photonic

Computing with light could slash the energy needs of neural networks

10 min read
Image of a computer rendering.

This computer rendering depicts the pattern on a photonic chip that the author and his colleagues have devised for performing neural-network calculations using light.

Alexander Sludds

Think of the many tasks to which computers are being applied that in the not-so-distant past required human intuition. Computers routinely identify objects in images, transcribe speech, translate between languages, diagnose medical conditions, play complex games, and drive cars.

The technique that has empowered these stunning developments is called deep learning, a term that refers to mathematical models known as artificial neural networks. Deep learning is a subfield of machine learning, a branch of computer science based on fitting complex models to data.

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