Robert L. Holman

Optical Damage Resistance Of Lithium Niobate Waveguides

The optical damage resistance of diffused lithium niobate wave-guides is discussed. Long-term laser power handling performance is assessed by recording the spatial intensity changes occurring as a function of time in a waveguides far field. Out-diffused waveguides are found to offer significantly greater long-term resistance to optical power losses caused by optical damage than do waveguides formed by either ion exchange or titanium in-diffusion. Any waveguides resistance to optical damage is lowered by inadvertent exposure to chemical reducing conditions that can prevail during device fabrication processes. Waveguides exposed to the severe chemical reducing conditions are found to exhibit dramatically nonlinear behavior when exposed to high laser powers and short laser wavelengths.

Desirability Of Electro-Optic Materials For Guided-Wave Optics

An illustrative, device-systems-level desirability optimization analysis is performed for a number of important electro-optic materials that are candidates for use in high-speed guided-wave optical devices. Ferroelectric materials with high and low transition temperatures, cubic crystals, organic crystals, and alloy semiconductors are considered. The simple bulk (lumped-type) guided-wave phase modulator is taken as the initial screening device. Performance measures such as electrical power supply constraints and the devices maximum operating speed are analyzed as a function of system variables that include material properties and electrode architectures. A desirability analysis is presented as a composite mathematical function that describes two or more indepen-dent performance measures in terms of all relevant system variables. This function is displayed graphically to identify those sets of system variables that jointly optimize the performance measures of greatest interest. The initial screening analysis ignores propagation loss and less-than-ideal overlap between electrical and optical fields. Potassium niobate, barium titanate, and lithium niobate are found to be among the more desirable electro-optic materials. The use of dielectric buffer layers, several thousand angstroms thick, is found necessary to isolate the modulator electrodes from materials of high dielectric constant, high electro-optic strength such as potassium niobate. Buffer layers, however, are generally unnecessary when the lower permittivity and lower electro-optic strength materials such as lithium niobate are used.

Processing Of Guided Wave Optoelectronic Materials

What follows is the edited transcript of a series of open discussions held Tuesday afternoon (4:20 - 6:00 PM) and Wednesday (10:30 AM - 12:00 PM and 5:10 PM -6:30 PM), January 21-22, 1986. Four separate discussions were held: 1. Open Discussion on Electrooptic Ferroelectrics Chairs: Doyle P. Skinner (Battelle) and Richard Becker (Crystal Technology, Inc.) 2. Open Discussion on III-V Semiconductors Chairs: Lynn D. Hutcheson (Honeywell, Inc.) and Robert L. Holman (Battelle) 3. Organic and Polymeric Electrooptics Chair: Gerald R. Meridith (E. I. DuPont de Nemours) 4. Wrap-Up Discussion on Status and Difficultiesin Practical Applications Chairs: Robert L. Holman (Battelle), S. Sriram (Allied-Amphenol) and Richard Becker (Crystal Technology, Inc.)

Lithium niobate waveguides and their susceptibility to optical damage

Abstract The laser power-handling characteristics of diffused lithium niobate waveguides are reviewed in terms of laser-power-coupled, transmission length, crystal orientation, and method of preparation. Laser-induced optical damage is recorded for the first time in the new proton-exchanged lithium niobate waveguides. Optical damage is not observed, however, for propagation along the z-axis of titanium-in-diffused waveguides.

The Optical Properties and Processing of Lithium Niobate Optical Waveguides

The laser-power-handling properties of planar out-diffused and in-diffused lithium niobate waveguides are considered in terms of fabrication process characteristics. The percentage of laser induced power-loss is found to increase as the square of both the input-coupled laser power and the beams transmission distance in the guide, regardless of the fabrication details. Titanium in-diffused waveguides are found not to exhibit laser-induced power-loss for beams proloaaatina along their z-axis.

The Desirability of Electrooptic Ferroelectric Materials for Guided-Wave Optics

An illustrative, device-systems-level desirability optimization analysis has been performed for a number of important electrooptic materials that are candidate for use in high-speed guided-wave optical devices. Ferroel ect r ic materials with high and low transition temperatures, cubic crystals, organic crystals, and alloy semiconductors have been considered. The bulk guided-wave phase modulator has been taken as the initial screening device. Performance measures such as electrical power supply constraints and the devices maximum operating speed have been analyzed as a function of system variables that include material properties and electrode architectures. Desirability analysis has been presented as a composite mathematical function that describes two or more independent performance measures in terms of all relevant system variables. This function has been displayed graphically to identify those sets of system variables that jointly optimize the performance measures o f greatest interest. The initial screening analysis has ignored propagation loss and less-than-ideal overlap between electrical and optical fields. Potassium niobate, barium titanate, and lithium niobate have been found to be among the more desirable electrooptic materials. The use of dielectric buffer layers, several thousand Angstroms in thickness, has been found necessary to isolate the modulator el high dielectric constant, high strength materials such as potass Buffer layers, however, have been generally unnecessary when using permittivity and lower electroopt materials such as lithium niobate. ctrodes f rom electroopt ic um niobate. ound to be the lower c strength

Battelle's Proposed Cooperative Program To Develop Guided Wave Optoelectronic Manufacturing Technology

The Battelle Memorial Institute is presently organizing a cooperative research and development program designed to facilitate rapid transition of optoelectronic technology from research to development. Specifically, the program will help U.S. industry develop the basic manufacturing technology it needs to produce active optoelectronic components efficiently and cost effectively for both long- and short-haul fiber optic systems. Manufacturing methods developed in the program are to be tested under pilot conditions so that fully packaged and connectorized prototypes are made available to the sponsoring companies at the earliest possible time. Three critical issues, microassembly and packaging, optical circuitry, and optoelectronic substrates, will be addressed in separate projects.

Environmental Testing Of Fused Fiber Couplers

The longterm reliability of fused fiber optic couplers is becoming an increasingly critical issue as the number of fiber optic systems being installed continues to rise. Components used in such systems are expected to meet their performance specifications over time periods measured in years. Maintaining such periods of stable and lasting environmental performance requires that particularly strong attention be paid to the component failure modes. In the case of fused fiber couplers, the specific steps of the manufacturing process and the design of the component package can interact in complex ways to influence environmental sensitivity and instigate performance failures.

Material Requirements for Guided-Wave Optical Devices

A quasi systems-level desirability analysis has been performed of candidate elec-trooptic materials for use in high-speed guided-wave optical devices. More than 30 inorganic, semiconducting, and organic materials have been compared. The bulk guided-wave phase modulator has been adopted as an initial basis for comparison. Drive voltage and current dynamics have been analyzed as a function of material properties and electrode architectures. Potassium niobate and lithium niobate are found to be among the more desirable materials. The III-V semiconductors and the low Curie temperature ferroelec-trics were found less desirable and, in some cases, marginal or even unacceptable for high-performance device applications.

Measurement Of Optical Damage In Lithium Niobate Waveguides

Use of optical waverides formed in lithium niobate single crystals is contemplated in a wide variety of promising modulation, switching, computation, and signal processing components. One factor, however, may stand in the way of this development: the degree to which the waveguides are susceptible to laser-induced performance degradations known as optical damage.