US team integrates QD lasers on silicon chiplets
In a new study 'Quantum Dot DBR Lasers Monolithically Integrated on Silicon Photonics by In-Pocket Heteroepitaxy' published in the IEEE Journal of Lightwave Technology, Rosalyn Koscica from the University of California and her team successfully integrated InAs lasers on silicon photonics chiplets.
The authors combined three key concepts: an 'in-pocket' laser strategy; a two-step material growth scheme that includes both MOCVD and MBE; and a polymer gap-fill approach to minimise optical beam divergence.
On testing, the chiplets demonstrated sufficiently low coupling loss such that the lasers could operate efficiently on a single O-band wavelength within chiplets. The O-band wavelength is desirable as it allows for transmission of signals within photonic devices with low dispersion. Lasing in a single frequency is achieved using ring resonators made from silicon or distributed Bragg reflectors made from silicon nitride.
“Our integrated QD lasers demonstrated a high temperature lasing up to 105 °C and a life span of 6.2 years while operating at a temperature of 35 °C,” says Koscica.
The laser integration technique has the potential to be adopted widely due to two reasons, according to Kosica. Firstly, the photonics chips can be manufactured in standard semiconductor foundries. Secondly, the QD laser integration technique can work for a range of photonic integrated chip design without needing extensive or complex modifications.
The team says the proposed integration technique can be applied to a variety of photonic integrated circuit designs by modifying the silicon photonics components, paving the way for a scalable, cost-effective monolithic integration of on-chip light sources for practical applications.
Reference
R. Koscica et al.; Journal of Lightwave Technology, vol. 43, no. 12, 15 June15, 2025
