Scientists demonstrated 1.3μm submilliamp threshold quantum dot micro-lasers on Si

September 18, 2017, Hong Kong University of Science and Technology
Schematic of the electrically pumped quantum dot micro-ring laser. Credit: Department of Electronic and Computer Engineering, HKUST

Decades ago, the Moore's law predicted that the number of transistors in a dense integrated circuit doubles approximately every two years. This prediction was proved to be right in the past few decades, and the quest for ever smaller and more efficient semiconductor devices have been a driving force in breakthroughs in the technology.

With an enduring and increasing need for miniaturization and large-scale integration of photonic components on the platform for data communication and emerging applications in mind, a group of researchers from the Hong Kong University of Science and Technology and University of California, Santa Barbara, successfully demonstrated record-small electrically pumped micro-lasers epitaxially grown on industry standard (001) silicon substrates in a recent study. A submilliamp threshold of 0.6 mA, emitting at the near-infrared (1.3?m) was achieved for a micro- with a radius of 5 μm. The thresholds and footprints are orders of magnitude smaller than those previously reported lasers epitaxially grown on Si.

Their findings were published in the prestigious journal Optica on August 4, 2017 (DOI: 10.1364/OPTICA.4.000940).

"We demonstrated the smallest current injection QD lasers directly grown on industry-standard (001) silicon with and high temperature stability," said Kei May Lau, Fang Professor of Engineering and Chair Professor of the Department of Electronic & Computer Engineering at HKUST.

"The realization of high-performance micron-sized lasers directly grown on Si represents a major step toward utilization of direct III-V/Si epitaxy as an alternate option to wafer-bonding techniques as on-chip silicon light sources with dense integration and low power consumption."

The two groups have been collaborating and has previously developed continuous-wave (CW) optically-pumped micro-lasers operating at room temperature that were epitaxially grown on silicon with no germanium buffer layer or substrate miscut. This time, they demonstrated record-small electrically pumped QD lasers epitaxially grown on silicon. "Electrical injection of micro-lasers is a much more challenging and daunting task: first, electrode metallization is limited by the micro size cavity, which may increase the device resistance and thermal impedance; second, the whispering gallery mode (WGM) is sensitive to any process imperfection, which may increase the optical loss," said Yating Wan, a HKUST PhD graduate and now postdoctoral fellow at the Optoelectronics Research Group of UCSB.

"As a promising integration platform, silicon photonics need on-chip laser sources that dramatically improve capability, while trimming size and power dissipation in a cost-effective way for volume manufacturability. The realization of high-performance micron-sized lasers directly grown on Si represents a major step toward utilization of direct III-V/Si epitaxy as an alternate option to wafer-bonding techniques," said John Bowers, Deputy Chief Executive Officer of AIM Photonics.

Explore further: Tiny lasers enable next-gen microprocessors to run faster, less power-hungry

More information: Yating Wan et al, 13 μm submilliamp threshold quantum dot micro-lasers on Si, Optica (2017). DOI: 10.1364/OPTICA.4.000940

Related Stories

Researchers develop powerful, silicon-based laser

September 29, 2014

A silicon-based laser that lases up to a record 111°C, with a threshold current density of 200 A/cm2 and an output power exceeding 100 mW at room temperature, has been demonstrated by collaborating researchers from University ...

Novel quantum dot laser paves the way for lower-cost photonics

March 3, 2014

With the explosive growth of bandwidth demand in telecommunications networks, experts are continually seeking new ways to transmit increasingly large amounts of data in the quickest and cheapest ways possible. Photonic devices—which ...

Low temperature heterogeneous integration without glue

May 24, 2016

Realization of large scale photonic integration for one-chip optical routers is crucial for future optical networks and interconnection for big data transmission and artificial intelligence technology. To meet these technical ...

Recommended for you

Diagnosing breast cancer using red light

March 23, 2018

Optical Mammography, or OM, which uses harmless red or infrared light, has been developed for use in conjunction with X-rays for diagnosis or monitoring in cases demanding repeated imaging where high amounts of ionizing radiation ...

Designing a new material for improved ultrasound

March 22, 2018

Development of a theoretical basis for ultrahigh piezoelectricity in ferroelectric materials led to a new material with twice the piezo response of any existing commercial ferroelectric ceramics, according to an international ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.