Silicon-Based Chip Produces a Laser Beam

A collaboration between the University of California, Santa Barbara, and Intel Corp. in Santa Clara, Calif., has produced what is thought to be the first electrically pumped, hybrid silicon/indium-phosphide laser. The continuous-wave device consists of a semiconductor quantum-well region bonded to a silicon waveguide. Radiation generated in the quantum-well region is evanescently coupled into the waveguide, which serves as a laser resonator.

A major obstacle that had to be overcome to demonstrate the hybrid laser was bonding the indium phosphide to the silicon. The two crystalline materials have a lattice mismatch that prevents conventional crystal bonding. The scientists finessed this problem by inserting a 25-atom-thick “glass glue” between the materials and pressing them together under low temperature to form the bond.

The scientists believe that their work will lead to high-volume, low-cost manufacture of monolithic chips with hundreds of individual hybrid silicon lasers. They envision chip-to-chip optical links communicating at terahertz rates.