Quintessent and the Tower Semiconductor team, collaborating under the DARPA LUMOS program, has demonstrated a world first in heterogeneously integrating O-band GaAs quantum dot (QD) lasers with a commercial foundry silicon photonics process.
Semiconductor quantum dot lasers and amplifiers offer several compelling benefits over traditional quantum well materials. These technological benefits are derived from the discrete, atom-like density of states and spatial localization inherent to QDs which contrasts with the stair-step density of states and large in-plane diffusion lengths in quantum wells. These fundamental differences in material physics translate into improved device properties including:
Lower relative intensity noise (RIN) in multiwavelength lasers
Optical amplifiers with near ideal noise figure
Improved optical feedback tolerance for isolator-free, on chip lasers
The ability to operate efficiently at high ambient temperatures
Significantly improved component reliability and lifetimes
Heterogeneous integration of lasers/amplifier functionality and other silicon photonic elements on common substrate presents significant benefits such as:
New product architectures and functionalities otherwise not achievable using external lasers, for example complete self-test at the chip level, or on-chip amplification
Reduced cost
Reduced power consumption and improved link margin
Improved system reliability
Integrating photonic elements together allows for fewer packages, including less material and fiber coupling costs. This integration also uses fewer optical fibers, reducing total cost and complexity of the fiber infrastructure and reducing the chip cost by reducing area on the chip used for fiber interfacing.
Thus, heterogeneous integration of quantum dot lasers with silicon photonics combines the best of both worlds above.
Read the original news announcement here.