Abstract
Abstract Breakthroughs in nanomaterials and nanoscience enable the development of novel photonic devices and systems ranging from the automotive sector, quantum cryptography to metropolitan area and access networks. Geometrical architecture presents a design parameter of device properties. Self-organization at surfaces in strained heterostructures drives the formation of quantum dots (QDs). Embedding QDs in photonic and electronic devices enables novel functionalities, advanced energy efficient communication, cyber security, or lighting systems. The recombination of excitons shows twofold degeneracy and Lorentzian broadening. The superposition of millions of excitonic recombinations from QDs in real devices leads to a Gaussian envelope. The material gain of QDs in lasers is orders of magnitude larger than that of bulk material and decoupled from the index of refraction, controlled by the properties of the carrier reservoir, thus enabling independent gain and index modulation. The threshold current density of QD lasers is lowest of all injection lasers, is less sensitive to defect generation, and does not depend on temperature below 80°C. QD lasers are hardly sensitive to back reflections and exhibit no filamentation. The recombination from single QDs inserted in light emitting diodes with current confining oxide apertures shows polarized single photons. Emission of ps pulses and date rates of 1010+bit upon direct modulation benefits from gain recovery within femtoseconds. Repetition rates of several 100 GHz were demonstrated upon mode-locking. Passively mode-locked QD lasers generate hat-like frequency combs, enabling Terabit data transmission. QD-based semiconductor optical amplifiers enable multi-wavelength amplification and switching and support multiple modulation formats.
Highlights
The discovery, development, and use of novel materials and technologies were decisive for the development of civilizations across the last ten thousand years
The threshold current density of quantum dots (QDs) lasers is lowest of all injection lasers, is less sensitive to defect generation, and does not depend on temperature below 80°C
It is straightforward to move to wurtzite structures, like GaN/AlN QDs, which show the advantage of much larger localization energies of the charge carriers and larger thermal stability, suggesting room-temperature operation of the single photon emitter (SPE)
Summary
The discovery, development, and use of novel materials and technologies were decisive for the development of civilizations across the last ten thousand years. The “light age”, as many are calling the 21st century, is characterized by the advent of novel illumination, communication, and alternative energy technologies based to a large extent on compound semiconductor devices, efficiently emitting, modulating, amplifying, or absorbing photons. Dingle and Henry did not discuss potential advantages of zero-dimensional structures in their patent application It took another 10 years, or until 1986 [21], for a group of researchers led by Suematsu at the Tokyo Institute of Technology to present a detailed theoretical comparison of gain and threshold current density for GaAs and InP-based zero-dimensional (quantum box) to 3D lasers, predicting enormous improvements for zero-dimensional “quantum box” lasers, like a strong reduction of the threshold current density. 42 years later, most of the semiconductor lasers are
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
