Nano Lasers in Photonic VLSI

We examine the use of micro and nano lasers to form digital photonic VLSI building blocks. Problems such as isolation and cascading of building blocks are addressed, and the potential of future nano lasers explored

Metal coated DBR/DFB lasers

Metallic nano-cavities can be used to fabricate lasers of sub-wavelength dimensions. Currently, these lasers emit their light through the substrate. This complicates measurements of these devices and their integration in optical systems. Side-emission offers a way to circumvent these problems. We plan to implement side-emission via distributed feedback; this allows accurate tuning of a cavity’s resonant wavelength and its emissive properties. In this paper we will give an update of the work that has been done

Metal coated DBR/DFB lasers

Metallic nano-cavities can be used to fabricate lasers of sub-wavelength dimensions. Currently, these lasers emit their light through the substrate. This complicates measurements of these devices and their integration in optical systems. Side-emission offers a way to circumvent these problems. We plan to implement side-emission via distributed feedback; this allows accurate tuning of a cavity’s resonant wavelength and its emissive properties. In this paper we will give an update of the work that has been done

Metallic DFB lasers

In this paper we present our latest results on the design, fabrication and characterization of metal coated DFB lasers. These devices are based on a specialform of the metal-insulator-metal waveguides, which support plasmon gap modes. The distributed feedback provides control over the laser ~ wavelength and its emissive properties. The size of the semiconductor core can be as small as 100 nm, which is well below the d~ffraction limit of light. The devices operate in the near-infrared and may eventually be suitablefor low-power, high-speed applications

Metallic DFB lasers

In this paper we present our latest results on the design, fabrication and characterization of metal coated DFB lasers. These devices are based on a specialform of the metal-insulator-metal waveguides, which support plasmon gap modes. The distributed feedback provides control over the laser ~ wavelength and its emissive properties. The size of the semiconductor core can be as small as 100 nm, which is well below the d~ffraction limit of light. The devices operate in the near-infrared and may eventually be suitablefor low-power, high-speed applications

Semiconductor-metal core-shell plasmonic nanolasers with a bowtie antenna cross section

A new plasmonic bowtie nanolaser structure is fabricated where a semiconductor gain core is enclosed by a metal shell with bowtie cross section built-in. Light emission characteristics under electrical injection will be reported

Gravitational uncertainties from dimension-six operators on supersymmetric GUT predictions

We consider the gravity induced dimension six terms in addition to the dimension five terms in the SUSY GUT Lagrangian and find that the prediction for $\alpha_s$ may be washed out completely in supersymmetric grand unified theories unless the triplet higgs mass is smaller than $7\times 10^{16}$ GeV.Comment: 7 pages,latex.Title of original version changed,text added and a figure has been added.Figure is available on request.To appear as a brief Report in Phys.Rev.

Improving Multiple-CMP Systems Using Token Coherence

Improvements in semiconductor technology now enable Chip Multiprocessors (CMPs). As many future computer systems will use one or more CMPs and support shared memory, such systems will have caches that must be kept coherent. Coherence is a particular challenge for Multiple-CMP (M-CMP) systems. One approach is to use a hierarchical protocol that explicitly separates the intra-CMP coherence protocol from the inter-CMP protocol, but couples them hierarchically to maintain coherence. However, hierarchical protocols are complex, leading to subtle, difficult-to-verify race conditions. Furthermore, most previous hierarchical protocols use directories at one or both levels, incurring indirections—and thus extra latency—for sharing misses, which are common in commercial workloads. In contrast, this paper exploits the separation of correctness substrate and performance policy in the recently-proposed token coherence protocol to develop the first M-CMP coherence protocol that is flat for correctness, but hierarchical for performance. Via model checking studies, we show that flat correctness eases verification. Via simulation with micro-benchmarks, we make new protocol variants more robust under contention. Finally, via simulation with commercial workloads on a commercial operating system, we show that new protocol variants can be 10-50% faster than a hierarchical directory protocol

Current status and prospects of photonic IC technology

The most complex photonic ICs today have been developed for WDM applications. An overview of the most important integration technologies will be given and recent developments towards broader applications and higher integration densities will be discussed