Joseph P. Donnelly

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Water quality data on Se and Fe have been collected since April 2003 in a study area of the lower Arkansas River valley, Colorado. Data were obtained from 19 surface water locations and from 50 ground water monitoring wells using low-flow sampling techniques. GIS mapping and statistical analysis were used to characterize the occurrence, severity, and(More)
In this work, we modified our wafer-scale 3D integration technique, originally developed for Si, to hybridize InP-based image sensor arrays with Si readout circuits. InGaAs image arrays based on the InGaAs layer grown on InP substrates were fabricated in the same processing line as silicon-on-insulator (SOI) readout circuits. The finished 150-mm-diameter(More)
— We investigate the noise figure (NF) of high-power semiconductor InGaAsP optical amplifiers (SOAs) based on the slab-coupled optical waveguide (SCOW) concept having both ultralow optical confinement (∼ 0.5%) and low optical loss (α i ∼ 0.5 cm −1). At 1550 nm and 5-A current bias, the NF of SCOW amplifier (SCOWA) is 5.5 dB, and the small-signal gain and(More)
Citation Younger, Richard D. et al. " Crosstalk analysis of integrated Geiger-mode avalanche photodiode focal plane arrays. " Advanced Photon Counting Techniques III. Arrays of photon-counting Geiger-mode avalanche photodiodes (APDs) sensitive to 1.06 and 1.55 µm wavelengths and as large as 256 x 64 elements on 50 µm pitch have been fabricated for defense(More)
A slab-coupled optical waveguide laser is wavelength stabilized with a fiber Bragg grating and characterized under a narrow pulse high repetition rate direct modulation scheme suitable for efficient pulse position modulation format optical communication systems.
Keywords: A2. Metalorganic vapor phase epitaxy A3. Quantum wells A3. Semiconducting III–V materials B3. Heterojunction semiconducting devices B3. Quantum cascade lasers a b s t r a c t Strain-compensated (SC) GaInAs/AlInAs/InP multiple-quantum-well structures and quantum cascade lasers (QCLs) with strain levels of 1% and as high as 1.5% were grown by(More)
We present the first quantitative investigation of noise figure degradation in InGaAsP quantum-well semiconductor optical amplifiers at high bias. We compare two experimental measurements of population inversion factor for a 1.5-μm slab-coupled optical-waveguide amplifier (SCOWA).
• Hybrid and monolithic two-dimensional surface-emitting arrays of GaAs/AlGaAs diode lasers have been designed and fabricated. The hybrid devices consist oflinear arrays ofedge-emitting graded-index: separate-confinement-heterostructure singIe-quantum-well (GRIN-SCH-SQW) lasers mounted on a Si substrate containing integral 45° deflecting mirrors and(More)
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