The Duke team developed a method of taking the thick substrate off of a laser, and bonding this thin film laser to silicon. The lasers are about one one-hundreth of the thickness of a human hair. These lasers are connected to other structures by laying down a microscopic layer of polymer that covers one end of the laser and goes off in a channel to other components. Each layer of the laser and light channel is given its specific characteristics, or functions, through nano- and micro-fabrication processes and by selectively removing portions of the substrate with chemicals.
“In the process of producing light, lasers produce heat, which can cause the laser to degrade,” Sabarni said. “We found that including a very thin band of metals between the laser and the silicon substrate dissipated the heat, keeping the laser functional.”
For Jokerst, the ability to reliably facilitate individual chips or components that “talk” to each other using light is the next big challenge in the continuing process of packing more processing power into smaller and smaller chip-scale packages.
“To use light in chip-scale systems is exciting,” she said. “But the amount of power needed to run these systems has to be very small to make them portable, and they should be inexpensive to produce. There are applications for this in consumer electronics, medical diagnostics and environmental sensing.”