Self-assembled InAs/InP quantum dots and quantum dashes: Material structures and devices

Abstract

The advances in lasers, electronic and photonic integrated circuits (EPIC), optical interconnects as well as the modulation techniques allow the present day society to embrace the convenience of broadband, high speed internet and mobile network connectivity. However, the steep increase in energy demand and bandwidth requirement calls for further innovation in ultra-compact EPIC technologies. In the optical domain, innovation in the laser technologies beyond the current quantum well (Qwell) based laser technologies are already taking place and presenting very promising results. Homogeneously grown quantum dot (Qdot) lasers, can serve in the future energy saving information and communication technologies (ICT) as the work-horse for transmitting information through optical fiber. The encouraging results in the zero-dimensional (0D) structures emitting at 980 nm, in the form of vertical cavity surface emitting laser (VCSEL), are already operational at low threshold current density and capable of 40 Gbps error-free transmission at 108 fJ/bit. Eventual achievements for lasers operating in the O-, C-, L-, U-bands, and beyond will eventually lay the foundation for green ICT. On the hand, the inhomogeneously grown quasi 0D quantum dash (Qdash) lasers are brilliant solutions for potential broadband connectivity in server farms or access network. A single broadband Qdash laser operating in the stimulated emission mode can replace tens of discrete narrow-band lasers in dense wavelength division multiplexing (DWDM) transmission thereby further saving energy, cost and footprint. In this article, we review the progress of both Qdots and Qdash devices based on the InAs/InGaAlAs/InP and InAs/InGaAsP/InP material systems, from the angles of growth and device performance.2

Modelling the enhancement of spectrally broadband extraction efficiency of emission from single InAs/InP quantum dots at telecommunication wavelengths

“…Recently, we have demonstrated optimization of the photonic environment to tailor the polarization anisotropy of emission from a single quantum emitter of an InAs/AlGaInAs/InP material system [18]. Hereby, we focus on the improvement of [16,21,[26][27][28][29], which can be interchanged in the fabrication of nanophotonic devices aimed at the telecom range due to similar refractive index, therefore our approach is valid for both of them. The mesa is placed on monolithic InP -sample "A" -or a DBR on InP -sample "B" -as shown in Fig.…”

Recent progress in InAs/InP quantum dash nanostructures and devices

“…This new class of dot-like nanostructure possesses both the features of quantum dot and quantum wire [1,2] and is highly attractive in optoelectronic device applications, thanks to the ultra-broad gain profile (>300 nm) and wide range of wavelength tenability of Qdashes covering C -L -U communication bands (~1400 nm to >2000 nm) [1]. Furthermore, devices based on self-assembled Qdash active region have demonstrated a number of unique qualities like, ultra-broad emission under stimulated (lasers) and amplified spontaneous (superluminescent diodes) emissions regimes, fast index and gain dynamics, and the capability of amplifying multiple wavelengths without any crosstalk (SOA).…”

“…In general, this has been attributed to the carrier localization in noninteracting or spatially isolated dot/dash in a highly inhomogeneous system. Such broadband light emitters are in great demand in highly-sensitive sensing, spectroscopy, optical telecommunications, eye-safe low-speckle sources for flash lidar and high resolution bio-imaging particularly optical coherence tomography (OCT) [1].…”

Class-A operation of an optically-pumped 16 µm-emitting quantum dash-based vertical-external-cavity surface-emitting laser on InP

“…On the other hand, as a result of the advantages offered by the quantification of lowdimensional quantum systems in terms of lower threshold current, broader gain response or improved thermal stability with respect to quantum wells, quantum dash-based active media have been extensively studied in the past [13]. Most of the contributions presented in the literature are related to edge-emitting and mode-locked lasers or semiconductor optical amplifiers [13,14], with some works on micrometer-long-cavity VCSELs, for which a well-defined and stable linear state-of-polarization [15,16], and a very wide gain bandwidth [17] were reported. It is thus interesting to investigate the behavior of such nanostructured semiconductor active medium in an external-cavity configuration, in order to benefit from the long-cavity setup in terms of laser linewidth and intensity noise performances.…”