Two research groups have reported independent approaches to the fabrication of the first electrically injected indium phosphide (InP)-based diode lasers on silicon. Such lasers, if practical, would help to usher in low-cost but extremely rapid data transmission. In both approaches, the light from the lasers was coupled into silicon-on-insulator (SOI) waveguides on silicon chips. In the method developed by a group from Intel (Santa Clara, CA) and the University of California-Santa Barbara (Santa Barbara, CA), an oxide layer a few nanometers thick is created on the InP component, which is heated and pressed against the SOI, bonding them. The silicon serves as the continuous-wave laser cavity, which is 800 µm long. The technology should make data-transmission speeds of 20 to 40 Gbit/s over distances of tens of feet possible, says Intel. Contact Barbara Bronson Gray at [email protected].
In the approach taken by researchers at Ghent University (Ghent, Belgium) and the Technical University Eindhoven (Eindhoven, The Netherlands), an InP-based laser structure is bonded to SOI with an adhesive called DVS-BCB. A polymer waveguide adiabatically couples 0.9 mW of 1550 nm laser light (via tapering) into an SOI waveguide. In this setup, the laser (if made shorter) can be used as a photodetector with a responsivity of 0.23 A/W. Contact Gunther Roelkens at [email protected].