High-Performance Silicon-Based Multiple Wavelength Source

We demonstrate a stable CMOS-compatible on-chip multiple-wavelength source by filtering and modulating individual lines from a frequency comb generated by a microring resonator optical parametric oscillator.. We show comb operation in a low-noise state that is stable and usable for many hours. Bit-error rate measurements demonstrate negligible power penalty from six independent frequencies when compared to a tunable diode laser baseline. Open eye diagrams confirm the fidelity of the 10 Gb/s data transmitted at the comb frequencies and the suitability of this device for use as a fully integrated silicon-based WDM source.Comment: 3 pages, 3 figure

Evaluation of a dietary screener: The Mediterranean Eating Pattern for Americans tool

Background: Evidence exists for an association between accordance with a Mediterranean diet pattern and slower rates of cognitive decline. However, an ‘Americanized’ version of the Mediterranean diet screener is needed to assess accordance in the USA. Thus, the Mediterranean Eating Pattern for Americans (MEPA) tool was developed to assess accordance with a Mediterranean-like food pattern when time is limited. The present study aimed to determine whether the MEPA screener captured the key elements of the Mediterranean diet compared to the more comprehensive food frequency questionnaire (FFQ). Methods: The study comprised a cross-sectional study in which 70 women completed both the VioScreen™ FFQ (Viocare, Princeton, NJ, USA) electronically and the 16-item MEPA screener, either electronically or by telephone, aiming to evaluate the inter-method reliability of the proposed screener. The convenience sample included patients (n = 49) and healthcare providers (n = 21) recruited from a tertiary care medical center. Results: The overall score from the MEPA screener correlated with corresponding overall MEPA FFQ score (ρ = 0.365, P = 0.002). Agreement between screener items and FFQ items was moderate-to-good for berries (κ = 0.47, P \u3c 0.001), nuts (κ = 0.42, P \u3c 0.001), fish (κ = 0.62, P \u3c 0.001) and alcohol (κ = 0.64, P \u3c 0.001), whereas those for olive oil (κ = 0.33, P = 0.001) and green leafy vegetables (κ = 0.36, P = 0.0021) were fair. Usual intakes of potassium, magnesium, vitamin C, saturated fat, selected carotenoids, folate and fiber derived from the FFQ varied with MEPA screener scores in the anticipated directions. Conclusions: The MEPA screener captures several components of the Mediterranean style pattern, although further testing of the MEPA screener is indicated

Broadband enhancement of light emission in silicon slot waveguides

We investigate the light emission properties of electrical dipole emitters inside 2-dimensional (2D) and 3-dimensional (3D) silicon slot waveguides and evaluate the spontaneous emission enhancement (F_p) and waveguide coupling ratio (β). Under realistic conditions, we find that greater than 10-fold enhancement in F_p can be achieved, together with a β as large as 0.95. In contrast to the case of high Q optical resonators, such performance enhancements are obtained over a broad wavelength region, which can cover the entire emission spectrum of popular optical dopants such as Er. The enhanced luminescence efficiency and the strong coupling into a limited set of well-defined waveguide modes enables a new class of power-efficient, CMOS-compatible, waveguide-based light sources

Second-Harmonic Generation in Silicon Nitride Ring Resonators

The emerging field of silicon photonics seeks to unify the high bandwidth of optical communications with CMOS microelectronic circuits. Many components have been demonstrated for on-chip optical communications, including those that utilize the nonlinear optical properties of silicon[1, 2], silicon dioxide[3, 4] and silicon nitride[5, 6]. Processes such as second harmonic generation, which are enabled by the second-order susceptibility, have not been developed since the bulk $\chi^{(2)}$ vanishes in these centrosymmetric CMOS materials. Generating the lowest-order nonlinearity would open the window to a new array of CMOS-compatible optical devices capable of nonlinear functionalities not achievable with the?$\chi^{(3)}$ response such as electro-optic modulation, sum frequency up-conversion, and difference frequency generation. Here we demonstrate second harmonic (SH) generation in CMOS compatible integrated silicon nitride (Si3N4) waveguides. The $\chi^{(2)}$ response is induced in the centrosymmetric material by using the nanoscale structure to break the bulk symmetry. We use a high quality factor Q ring resonator cavity to enhance the efficiency of the nonlinear optical process and detect SH output with milliwatt input powers.Comment: 4 pages, 3 figure