For Dieter Bimberg, the growth of the quantum dot laser industry has a history stretching back more than thirty years. The devices now finding commercial markets grew out of questions that occupied his laboratory long before their present applications took shape. Looking back after iNOW 2026, he recalled the changes in scientific approach that made those devices possible, and described the opportunities he now sees in optical communications and quantum information.
Bimberg, a Fellow and Academic Council Member of CORE Academy, served as co-chair of the International Nano-Optoelectronics Workshop, held in Beijing and Tianjin in August 2026, and chaired its poster award committee. In his opening plenary, “Quantum Dot Lasers and Amplifiers for Energy-Efficient Multi Terabit Data Communication,” he returned to the early work on semiconductor nanostructures before turning to systems capable of transmitting trillions of bits of information each second.
The story begins with a problem of fabrication. Early attempts to make quantum dots through etching and related techniques, he recalled, had not yielded the room-temperature devices researchers were seeking. Progress came through a different understanding of how the structures could form. When one semiconductor is grown on another with a different crystal lattice spacing, the resulting strain can, under suitable conditions, drive the formation of nanoscale islands. This process offered a way to grow quantum dots within a semiconductor structure.
“The growth of semiconductor quantum dots is based on strain driven self-organization effects,” Bimberg explained. He and his collaborators developed an approach using Stranski–Krastanov growth, in which an initial layer is followed by three-dimensional islands. The challenge was to understand and control the conditions under which those islands formed. His work with Vitaliy Shchukin explored the physical principles behind this spontaneous ordering on crystal surfaces. [1]
Theory helped make sense of what researchers were growing. Quantum dots confine charge carriers within tiny regions, giving rise to discrete energy levels. Changing a dot's size or composition changes its optical properties. Bimberg and his colleagues developed models linking the structure and strain of a dot to its electronic states and interaction with light. The ability to explain these relationships gave researchers a firmer basis for designing devices. [2]
The applications depend partly on whether a device uses a single dot or an ensemble of many dots. An individual quantum dot always emits single polarized photons (q-bits), providing a means of carrying quantum information in light. Large numbers of dots, incorporated into the active region of a device, can supply the optical gain needed for lasers and amplifiers. Bimberg's account moves between these two scales, from the control of individual emission events to the generation of light for high-speed communications.
Courtesy of Shujie Pan, HS Photonics
One example is the mode-locked quantum dot laser. Such a laser can generate a frequency comb, a set of regularly spaced optical frequencies whose individual lines can carry separate data streams. With suitable modulation, many channels from one laser can together support transmission at multiple terabits per second. A single source can therefore supply many parallel channels of information.
Related research on quantum dot lasers grown directly on silicon has demonstrated this approach in a form relevant to integrated photonics. Bringing light sources together with photonic and electronic components is an important step toward compact communication systems. The promise of these devices rests on translating their optical performance into useful capacity and efficiency at the system level. [3]
At iNOW, these questions appeared alongside presentations on optical interconnects for AI and the convergence of photonics and electronics. Bimberg's contribution concerned the devices on which such systems depend. His reflections also highlighted quantum dot amplifiers, including reports of ultrashort pulses amplified without broadening and of multiple high-speed data channels amplified together. As communication demands grow, preserving the quality of a signal matters alongside generating it.
What particularly caught his attention, however, was the commercial activity around the technology. Decades after the early laser demonstrations, he described “an explosive growth of companies and their size bringing QD-lasers to market.” At Innolume, the German company he co-founded, he reported that the workforce was increasing from approximately 80 to 120 people.
Innolume's history makes the connection with academic research tangible. Founded in 2003, the company emerged from the long collaboration between the laboratories of Zhores Alferov at the Ioffe Institute and Bimberg at the Technical University of Berlin. Its development has included quantum dot wafer production, lasers, and optical amplifiers. The expansion Bimberg described is a recent chapter in that much longer undertaking. [4]
His outlook also reaches beyond technologies already entering the market. He drew attention to quantum dot structures with particular crystal symmetries as potential sources of entangled photons, with the prospect of operation at temperatures extending toward room temperature. He presented this as a research prospect, with room-temperature operation still an objective to explore.
There was a place for work in progress at iNOW as well. The poster program paired brief presentations with time for viewing and discussion, giving young researchers an opportunity to explain their results to an international audience. Bimberg's role in the poster awards brought this part of the meeting alongside his own retrospective account of the field.
Quantum dot research has reached a stage at which a scientist can look back on early experiments and see their descendants in commercial production, while still discussing possibilities that remain in the laboratory. For Bimberg, the growth of the industry is a substantial development in a scientific story he has helped shape. The early work continues to find new uses, even as researchers return to the material itself with new questions.
Prepared by CORE Academy from reflections shared by Professor Dieter Bimberg following iNOW 2026, the workshop program, and the research and institutional sources listed below.
References
1. Shchukin, V. A., and D. Bimberg. “Spontaneous ordering of nanostructures on crystal surfaces.” Reviews of Modern Physics 71 (1999): 1125. View source
2. Stier, O., M. Grundmann, and D. Bimberg. “Electronic and optical properties of strained quantum dots modeled by 8-band k·p theory.” Physical Review B 59 (1999): 5688. View source
3. Liu, S., et al. “High-channel-count 20 GHz passively mode locked quantum dot laser directly grown on Si with 4.1 Tbit/s transmission capacity.” arXiv:1812.04550 (2018). View source
4. Innolume. Company history and development milestones. View source
5. CORE Academy. Dieter Bimberg — Fellow profile. View source