It’s a problem chip manufacturers have known about for some time: As electronic components continue to grow more and more diminutive in size, the metal interconnects between them will soon cease to meet the needed performance criteria that devices demand.
This is where optical interconnectionsor using light instead of an electrical current as a transmission mediumcome into play. Engineers and physicists at MIT have devised a new method for integrating this photonic circuitry onto a silicon chip, a discovery that could soon add the power and speed of light waves to traditional electronics.
In fact, consumers could start to see entirely new devices, systems, and applications in computing and telecommunications that use “optics on a chip” within the next five years, MIT researchers said in a new study published in the Journal of Nature Photonics.
“Depending on the growth of the telecom industry, such devices could be in demand within five years,” said to Erich Ippen, professor of electrical engineering and physics and co-author of the study.
The new process, which allows for inter- and intra-chip communications networks that make the wiring problems of today’s computer chip and computer architectures obsolete, could even pave the way for integrated devices to be mass-manufactured for the first time.
Other potential applications include the advent of high-speed supercomputers on a chip, endowed with unique capabilities for signal processing, spectroscopy, and remote testing.
Read about CPUs on ExtremeTech.
According to Franz Kaertner, part of the MIT discovery team and a professor of electrical engineering and computer science, the main advantage in integrating optics with silicon technology is that silicon fabrication “is already highly developed and promises precise and reproducible processing of densely integrated circuits.”
In their quest to fabricate these new optical chips, the MIT researchers came up with a new way of molding light waves during a process known as microphotonics. By using two different materials that refract light differently, such as silicon and its oxides, photons can be trapped within a small hall of mirrors that, in turn, gives them new and unique properties.
To date, the problem with microphotonic devices has been that they tend to be susceptible to the polarities of light. This has meant that devices used in today’s photonic subsystems and optical communication networks can’t readily connect to the outside world without being hand-assembled piece by piece.
The new MIT method for integrating optics on a chip involves separating the two orientations of polarized light waves and, like polarizing sunglasses, use vertical polarizers to block the horizontally oriented light reflected from flat surfaces.
“These results represent a breakthrough in permitting the processing and switching of arbitrarily polarized input light signals in tightly confined and densely integrated photonic circuitry,” explained Ippen. And this will in turn make it possible to integrate optical components onto a single, mass-produced, silicon chip.