This Small Business Innovation Research (SBIR) Phase I project aims to develop silicon (Si) compatible light sources that will enable monolithic integration of electronic and photonic components on the same Si platform. A novel electrical pumping scheme will be investigated to convert germanium (Ge) from an indirect-bandgap to a pseudo-direct-bandgap material using ultra-high-density free electrons. The objective is to realize strong electroluminescence in the Ge thin film and thus demonstrate the feasibility of fabricating an electrically pumped nano-LED or laser within the complementary metal oxide semiconductor (CMOS) process flow.
The broader impact/commercial potential of this project will be a fundamental breakthrough in photonics technology that will benefit and possibly even revolutionize the industry that develops and markets communication systems, because it will supply the last missing link ? the light source ? required for true monolithic integration of photonic and electronic circuits on one low-cost Si platform. Extensive applications with potentially enormous markets would be enabled, ranging from chip-to-chip optical relays to long-haul optical communications.
Silicon (Si) is a very attractive platform in which to monolithically integrate electronic and photonic circuit components. Fundamental Si-compatible optoelectronic devices, such as Si modulators and Si photodetectors, have made great progress in recent decades to meet the performance and cost requirements of high speed optical communication systems and chip-level interconnections. A Si-compatible source of coherent light at wavelengths advantageous for propagation in optical fiber, however, is still one of the "holy grails" of modern optoelectronic technology. Extensive applications and enormously large markets awaiting such a breakthrough component range from long haul optical communications to short range chip-to-chip communications. In Phase I of this SBIR program, Photonic Systems Inc., together with Professor Axel Scherer of the California Institute of Technology, investigated a proprietary means of constructing the last missing link – the light source – required for the true monolithic integration of optical and electronic circuits on a Si platform. The feasibility of this device was experimentally demonstrated in Phase I by room-temperature measurement of a significant photon emission peak exactly at the 1550 nm wavelength in widespread use by the telecommunications industry. A high radiative efficiency of 65% was estimated based on laser rate equations. In Phase II of the SBIR program, we plan to demonstrate an experimental prototype of our Si-compatible coherent light source.
