OSHA reports that in 2016 there were 154 fatalities and 1640 non-fatal injuries from electrical exposure.<sup>1</sup> These incidents occurred even at sites with state-of-the art electrical safety programs. Such programs emphasize shutting off sources of electrical energy before exposure, which often occurs during maintenance, installation or other service activities. Nevertheless, exposures still occur, and GE’s research team has been investigating ways of alerting employees to unidentified energized sources. One means of reducing these exposure risks is the use of wearable electronics that would alert the user to energized sources. GE’s Global Research is actively pursuing projects to enhance worker safety with wire-free, lightweight, comfortable devices, and a voltage sensing wristband was developed to provide notification to service and repair workers of the presence of live alternating current circuits. The monitors are not a substitute for personal protective equipment (PPE), but are instead designed to supplement existing training, protocols as a last line and layer of defense. While non-contact voltage sensing devices exist, they do not have the desired sensitivity, comfort, form factor, or "wear and forget" operational mode that is desired for the service workforce. The research team worked closely with the field in specification development and refinement, and in rapidly creating and evaluating prototypes. Flexible circuit, sensor, and band were developed, iterated and field tested in several quick iterative turns. Flexible Hybrid Electronic (FHE) technology elements were used to integrate sensing, communication and computational elements together to create a conformable, bendable wristband. Important lessons were learned about the operating environment, user interface, wearability requirements, sensitivity and repeatability of the devices that drove further design iterations. This band may also serve as a modular platform for further development and enhancement of both the base capabilities and the addition of more diverse sensing capabilities.
The Rochester Imaging Detector Laboratory, University of Rochester, Infotonics Technology Center, and Jet Process
Corporation developed a hybrid silicon detector with an on-chip sigma-delta (ΣΔ) ADC. This paper describes the process
and reports the results of developing a fabrication process to robustly produce high-quality bump bonds to hybridize a
back-illuminated detector with its ΣΔ ADC. The design utilizes aluminum pads on both the readout circuit and the
photodiode array with interconnecting indium bumps between them. The development of the bump bonding process is
discussed, including specific material choices, interim process structures, and final functionality. Results include
measurements of bond integrity, cross-wafer uniformity of indium bumps, and effects of process parameters on the final
product. Future plans for improving the bump bonding process are summarized.
Photoacoustic spectroscopy (PAS) is a useful monitoring technique that is well suited for trace gas detection. This
method routinely exhibits detection limits at the parts-per-million (ppm) or parts-per-billion (ppb) level for gaseous
samples. PAS also possesses favorable detection characteristics when the system dimensions are scaled to a microsystem
design. Current research utilizes quantum cascade lasers (QCLs) in combination with micro-electromechanical
systems (MEMS)-scale photoacoustic cell designs. This sensing platform has provided favorable detection limits for a
standard nerve agent simulant. The objective of the present work is to demonstrate an extremely versatile MEMS-scale
photoacoustic sensor system that is able to discriminate between different analytes of interest.
Externally coupled electroabsorption modulators (EAM) are commonly used in order to transmit RF signals on
optical fibers. Recently an alternative device design with diluted waveguide structures has been developed.  Bench
tests show benefits of lower propagation loss, higher power handling (100 mW), and higher normalized slope efficiency.
This paper addresses the specific issues involved in packaging the diluted waveguide EAM devices. An evaluation
of the device requirements was done relative to the standard processes. Bench tests were performed in order to
characterize the optical coupling of the EAM. The photo current maximum was offset from the optical power output
maximum. The transmissions vs. bias voltage curves were measured, and an XY scanner was used to record the mode
field of the light exiting from the EAM waveguide in each position. The Beam Propagation Method was used to simulate
the mode field and the coupling efficiency. Based on the bench tests and simulation results, a design including
mechanical, optical and RF elements was developed. A Newport Laser Welding system was utilized for fiber placement
and fixation. The laser welding techniques were customized in order to meet the needs of the EAM package design.
An electroabsorption modulator (EAM) is designed to optimize dynamic range performance over 20
GHz bandwidth. The single stripe waveguide enables an extremely compact and integrated package to
be fabricated with single mode fiber pigtails. The transfer function's shape permits suppression of
higher order intermodulation products, yielding a spur-free dynamic range exceeding that of Mach-
Zehnder designs. A dilute optical core diverts energy flow from absorbing layers into low loss
waveguide; the 20 dBm optical power tolerance is significantly higher than that of commercially
available electroabsorption devices. The tunable performance over 20 GHz is characterized and
applications are discussed. New approaches to the broadband impedance matching requirements are
calculated and the impact on system performance is assessed.
The Air Force Research Laboratory, Binoptics Corp., and Infotonics Technology Center worked collaboratively to package and characterize recently developed diode based ring lasers that operate at 1550 nm in a diamond shaped cavity. The laser modes propagate bi-directionally; however, uniaxial propagation may be induced by optical injection or by integrating a mirror. Round trip cavity length was 500 μm in 3.5 μm wide ridge waveguides, and four polarization-maintaining lensed fibers provided access to the input and output modes. A signal from a tunable diode laser, incident at one port, served to injection lock both of the counter-propagating circulating modes. When the input signal was time-encoded by an optical modulator, the encoding was transferred to both modes with an inverted time-intensity profile. Performance, in terms of fidelity and extinction ratio, is characterized for selected pulsed and monochromatic formats from low frequencies to those exceeding 12 GHz. A rate equation model is proposed to account for certain aspects of the observed behavior and analog and digital applications are discussed.