William J. Minford

Accelerated Life Testing and Reliability of High K Multilayer Ceramic Capacitors

The reliability of high K muitilayer ceramic capacitors was evaluated using accelerated life testing. The degradation in insulation resistance was characterized as a function of voltage (two to eight times rated) and temperature (85 to 170°C). The times to failure at a voltage-temperature stress conformed to a iognormai distribution with a standard deviation typically less than 0.5. A small infant mortality population was also observed for some samples. The results were least-squares fit to the following equation:

Guided-wave optical time delay network

A hybrid optical time delay unit using lithium niobate switches and precisely produced fiber loops is described. Three prototypes of the device were fabricated and characterized. The measured optical extinction ratio between time slots is typically /spl Lt/25 dB. On average, delay values are within 0.7% of their design values. The device is a 6-b (64 time slot) delay unit with 44 picosecond per increment.

Interferometric Fiber Optic Gyroscope Using a Novel 3x3 Integrated Optic Polarizer/Splitter

A Ti:LiNbO3 3x3 directional coupler, acting as both polarizer and 3db splitter, with a phase modulator has been incorporated in an interferometric fiber optic gyroscope. A random walk performance of 1x10^-20h has been demonstrated.

Radiation effects on proton-exchange waveguides

We have measured the effects of electrons on LiNbO3 proton exchange waveguides. We have measured the attenuation and polarization component cross talk out of situ. These measurements were made using the 3 MeV Lehigh University Van de Graaff Facility.

Radiation Effects on LiNbO3 Devices

We report here the results of irradiating LiNb03 optical devices. Various types of devices were irradiated. These include wave guides, bidirectional couplers, and delta beta switches. The radiation used was gamma rays and electrons. The experimental techniques and the results are described below.

Proton radiation effects on various electro-optical devices

We have measured the effects of electron and proton radiation on LiNbO3 electro-optical devices. These include waveguides, switches, Mach-Zender interferometers, etc., of both Ti indiffused and proton exchange construction. The effects of continuous and pulsed beam in situ and out of situ were measured.

Radiation effects on dynamical behavior of LiNbO3 switching devices

The dynamical properties of LiNbO3 switches were measured as a function of radiation. The devices are titanium indiffused delta beta switches. Measurements of the gamma radiation level using radiation monitors indicate a total dose of less than 100 rad for a 5-min gamma exposure. The dc levels attenuate for the unswitched case, but not to the same degree that the switched signals do. With pulsed beam, a pulsed attenuation of the signal is evident.

Integrated optics for fiber optic sensors

Recent progress achieved in the field of fiber-optic sensor applications is discussed with emphasis placed on LiNbO3-based integrated optics (IO). Particular consideration is given to advanced electromagnetic-field sensors, an integrated laser vibrometer system, and a fiber-optic gyroscope system. It is shown that the multifunction IO chips have enabled high perforamance fiber-optic sensors (e.g., fiber-optic gyros), provided advanced and unique signal processing capabilities and advanced architectures, and have a potential of making fiber-optic sensors at low cost.