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Nanoscale semiconductor lasers have been developed recently using either metal, metallo-dielectric, or photonic crystal nanocavities. While the technology of nanolasers is steadily being deployed, their expected performance for on-chip optical interconnects is still largely unknown due to a limited understanding of some of their key features. Specifically, as the cavity size is reduced with respect to the emission wavelength, the stimulated and the spontaneous emission rates are modified, which is known as the Purcell effect in the context of cavity quantum electrodynamics. This effect is expected to have a major impact in the "threshold-less" behavior of nanolasers and in their modulation speed; but its role is poorly understood in practical laser structures, characterized by significant homogeneous and inhomogeneous broadening and by a complex spatial distribution of the active material and cavity field. In this paper, we investigate the role of the Purcell effect in the stimulated and spontaneous emission rates of semiconductor lasers taking into account the carriers' spatial distribution in the volume of the active region over a wide range of cavity dimensions and emitter/cavity linewidths, enabling the detailed modeling of the static and dynamic characteristics of either micro- or nano-scale lasers using single-mode rate-equations analysis. The ultimate limits of scaling down these nanoscale light sources in terms of Purcell enhancement and modulation speed are also discussed showing that the ultrafast modulation properties predicted in nanolasers are a direct consequence of the enhancement of the stimulated emission rate via reduction of the mode volume. [ABSTRACT FROM AUTHOR]

As massive microprocessors with thousands of cores are on the horizon, using Radio Frequency (RF) or state-of-the-art nanophotonic on-chip interconnects appears as a solution to cope with current latency constraints. Due to their reliance on numerous static circuitry to generate communication channels, proposed architectures cannot rearbitrate the available bandwidth to on-chip nodes according to instantaneous traffic demands. In this paper, we present an Orthogonal Frequency Division Multiple Access (OFDMA) based wired on-chip RF interconnect as an effective reconfigurable and broadcast capable modulation. A hierarchical 2048-core CMP architecture is explained along with its hybrid cache coherency mechanism. Based on this novel architecture, we introduce an innovative bandwidth arbitration mechanism which allocates more bandwidth to cache-line carrying long packets without requiring extra signaling overhead. Exploiting broadcast capability and effective reconfigurability, we show that this bimodal packet aware communication infrastructure can provide up to 10 × less average latency compared to a static counterpart under certain circumstances. [ABSTRACT FROM AUTHOR]

On-chip nanophotonics offer high throughput, yet energy-efficient communication, traits that can prove critical to the continuance of multicore chip scalability. In this paper, we investigate and propose silicon nanophotonic components that are embedded entirely in the silica (SiO2) substrate, i.e., reside subsurface, as opposed to die on-surface silicon nanophotonics of prior-art. Among several offered advantages, such silicon-in-silica (SiS) nanophotonic structures empower the implementation of nonobstructive interconnect geometries that deliver an improved power-performance balance, as demonstrated experimentally. First, using exhaustive simulations based on commercial-grade optical software-based tools, we show that such SiS structures are feasible, and derive their geometry characteristics and design parameters. As a second step, utilizing SiS optical channels and filters, we then design two distinct SiS-based nanophotonic network-on-chip (PNoC) mesh-diagonal links topologies as a means of demonstrating our proof of concept. In further pushing the performance envelope, we next develop: 1) an associated contention-aware adaptive routing function and 2) a parallelized photonic channel allocation scheme, with both coupled to SiS-based PNoCs as elements, to respectively replace under-performing routing and flow-control photonic protocols currently utilized. An extensive experimental evaluation, including utilizing traffic benchmarks gathered from full-system chip multiprocessor simulations, shows that our methodology boosts network throughput by up to 59.7%, reduces communication latency by up to 78.7%, while improving the throughput-to-power ratio by up to 31.6% when compared to the state-of-the-art. [ABSTRACT FROM PUBLISHER]

In this paper, a type of compact nanosensor based on a metal-insulator-metal structure is proposed and investigated through cascading double asymmetric cavities, in which their metal cores shift along different axis directions. The cascaded asymmetric structure exhibits high transmission and sharp Fano resonance peaks via strengthening the mutual coupling of the cavities. The research results show that with the increase of the symmetry breaking in the structure, the number of Fano resonances increase accordingly. Furthermore, by modulating the geometrical parameters appropriately, Fano resonances with high sensitivities to the changes in refractive index can be realized. A maximum figure of merit (FoM) value of 74.3 is obtained. Considerable applications for this work can be found in bio/chemical sensors with excellent performance and other nanophotonic integrated circuit devices such as optical filters, switches and modulators. [ABSTRACT FROM AUTHOR]

Surface plasmons provide a pathway to efficiently absorb and confine light in metallic nanostructures, thereby bridging photonics to the nano scale. The decay of surface plasmons generates energetic 'hot' carriers, which can drive chemical reactions or be injected into semiconductors for nano-scale photochemical or photovoltaic energy conversion. Novel plasmonic hot carrier devices and architectures continue to be demonstrated, but the complexity of the underlying processes make a complete microscopic understanding of all the mechanisms and design considerations for such devices extremely challenging.Here,we review the theoretical and computational efforts to understand and model plasmonic hot carrier devices.We split the problem into three steps: hot carrier generation, transport and collection, and review theoretical approaches with the appropriate level of detail for each step along with their predictions.We identify the key advances necessary to complete the microscopic mechanistic picture and facilitate the design of the next generation of devices and materials for plasmonic energy conversion. [ABSTRACT FROM AUTHOR]

Nanophotonic integrated circuits offer unique advantages for studying the interaction of light fields with mechanical structures. Because nanoscale waveguides are closely size-matched to nanomechanical devices, strong optomechanical interactions arise which can be harnessed in optical systems. The additional mechanical degrees of freedom provided by optomechanical devices are of particular interest for material systems in which tunability of the optical properties is not readily available. Here, suitable materials for the realization of chip-based optomechanical circuits are discussed and analyzed in terms of performance and the achievable quality factors. In particular, materials that offer large electronic band gaps are of interest, because in this case broadband optical transparency is achieved, combined with reduced free carrier effects. Several device geometries that can be used for enhancing optical forces are presented which address both an increase in the field gradient and the net optical force through resonant enhancement. Combining a variety of optomechanical components into full circuits thus provides a new route toward functional nanophotonic circuits with applications in sensing and optical signal processing in a chip-scale framework. [ABSTRACT FROM PUBLISHER]

Bigradient all‐dielectric metamaterials provide subwavelength‐scale on‐chip metalenses solution for dense photonic integrated circuits by structural engineering. (DOI: 10.1002/inf2.12264) [ABSTRACT FROM AUTHOR]