The development of ultralow-loss silicon-nitride-based waveguide platforms has enabled the realization of integrated optical filters with unprecedented performance. Such passive circuits, when combined with phase modulators and low-noise lasers, have the potential to improve the current state of the art of the most critical components in coherent communications, beam steering, and microwave photonics applications. However, the large refractive index difference between silicon nitride and common III-V gain materials in the telecom wavelength range hampers the integration of electrically pumped III-V semiconductor lasers on a silicon nitride waveguide chip. Here, we present an approach to overcome this refractive index mismatch by using an intermediate layer of hydrogenated amorphous silicon, followed by the microtransfer printing of a prefabricated III-V semiconductor optical amplifier. Following this approach, we demonstrate a heterogeneously integrated semiconductor optical amplifier on a silicon nitride waveguide circuit with up to 14 dB gain and a saturation power of 8 mW. We further demonstrate a heterogeneously integrated ring laser on a silicon nitride circuit operating around 1550 nm. This heterogeneous integration approach would not be limited to silicon-nitride-based platforms: it can be used advantageously for any waveguide platform with low-refractive-index waveguide materials such as lithium niobate.
Single-photon sources and detectors are indispensable building blocks for integrated quantum photonics, a research eld that is seeing ever increasing interest for numerous applications. In this work we implemented essential components for a Quantum Key Distribution (QKD) transceiver on a single photonic chip. Plasmonic antennas 1 on top of silicon nitride waveguides provide Purcell enhancement with a concurrent increase of the count rate, speeding up the microsecond radiative lifetime of IR-emitting colloidal PbS/CdS Quantum Dots (QDs). The use of low-uorescence silicon nitride with a waveguide loss smaller than 1 dB/cm, made it possible to implement high extinction ratio optical lters and low insertion loss spectrometers. Waveguide-coupled Superconducting Nanowire Single-Photon Detectors (SNSPDs) allow for low time-jitter single-photon detection. To showcase the performance of the components, we demonstrate on-chip lifetime spectroscopy of PbS/CdS QDs. The method developed in this paper is predicted to scale down to single QDs and newly developed emitters can be readily integrated on the chip-based platform.
Colloidal quantum dots (QDs) are an attractive light source for visible photonics, in particular their widely tunable emission wavelength, inexpensive wet-chemical synthesis and straight-forward hybrid integration can make the difference. In this work, integrated light-emitting diodes are demonstrated based on CdSe/CdS QDs, with the emission directly coupled to a silicon nitride waveguide. The devices feature a record current density of up to 100 A cm −2 and a maximum on-chip power density of almost 1.5 W cm −2 in a single-mode waveguide. Operated as detectors, the photodiodes have a low dark current of 1.5 µA cm −2 . It is anticipated, that the devices will find an application in chip-based absorption spectroscopy and bio-sensing, as they can be post-processed on foundry-fabricated waveguide platforms, at a low cost. In addition, this approach provides the missing low-loss waveguide layer, necessary for building an electrically pumped laser using colloidal QDs.
Colloidal quantum dots (QDs) have become an attractive light source for visible photonics. Here, we demonstrate the first integrated LED based on CdSe/CdS QDs, with the emission directly coupled to a silicon nitride waveguide.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.