Image Courtesy Purdue University

Researchers at Purdue University have developed a "passive optical diode" that does not require any external inputs to transmit signals. It is also so small that millions would fit onto a conventional computer chip, potentially yielding faster and more powerful data processing and supercomputers.

The new diode is made from two silicon rings that measure just 10 microns in diameter, which is about one-tenth the width of a human hair. After being transmitted through an optical fiber, infrared light from a laser at telecommunications wavelength is guided by a microstructure called a waveguide. It then passes sequentially through two silicon rings and undergoes "nonlinear interaction" while inside the tiny rings.

Depending on which ring the light enters first, it will either pass in the forward direction or be dissipated in the backward direction, making for one-way transmission. The rings can be tuned by heating them using a "microheater," which changes the wavelengths at which they transmit, making it possible to handle a broad frequency range.

Being composed of silicon, the optical diodes are compatible with current industry manufacturing processes for complementary metal-oxide-semiconductors (CMOS) used to produce computer chips.


Purdue Newsroom - New device could bring optical information processing

Ultrafast Optics and Optical Fiber Communications Laboratory