Mark S. Zediker

Curved waveguides for spatial mode filters in semiconductor lasers

Curved waveguides are used as a lateral spatial mode filter to increase the threshold for the first-order mode in high-power narrow stripe semiconductor lasers. Beam propagation analysis is used to determine optimal waveguide geometries and radii of curvature to establish appropriate amounts of bend loss. Curved waveguide devices are fabricated and compared against conventional devices. Use of a curved waveguide increases the current level at which lateral beam instabilities occur from /spl sim/400 to /spl sim/700 mA with no decline in slope efficiency.

900-mW high brightness buried ridge lasers by selective area epitaxy

A study has been made of high power single lateral mode buried ridge lasers fabricated by selective area epitaxy. Several ridge thicknesses have been evaluated simultaneously in a single fabrication run. These lasers operate purely in the fundamental mode to output powers in excess of 450 mW, after which they are subject to beam steering or higher order mode operation. For weakly guided lasers, the output remains in a narrow lobe [full-width at half-maximum (FWHM)] = 4/spl deg/-6/spl deg/, stable at a given current value, up to output powers of 900 mW in CW tests.

10-amplifier coherent array based on active-integrated optics

Recent advances in the development of a 10-amplifier active integrated-optic device are reviewed. High coherence is demonstrated for the array, which integrated power splitters, turning mirrors, phase modulators, and optical amplifiers on a single chip. Techniques for controlling the most significant parameters, the rib dimensions and the turning mirror roughness, are described. The performance of the various component and integrated devices is discussed.

High-power direct-diode laser successes

Direct diode laser will become much more prevalent in the solar system of manufacturing due to their high efficiency, small portable size, unique beam profiles, and low ownership costs. There has been many novel applications described for high power direct diode laser [HPDDL] systems but few have been implemented in extreme production environments due to diode and diode system reliability. We discuss several novel applications in which the HPDDL have been implemented and proven reliable and cost-effective in production environments. These applications are laser hardening/surface modification, laser wire feed welding and laser paint stripping. Each of these applications uniquely tests the direct diode laser systems capabilities and confirms their reliability in production environments. A comparison of the advantages direct diode laser versus traditional industrial lasers such as CO2 and Nd:YAG and non-laser technologies such a RF induction, and MIG welders for each of these production applications is presented.

Novel design for high-power single-lateral-mode lasers

A new laser design for single-mode high-power applications is reported. The waveguide is a laterally flaring and transversely tapering GaAs buried ridge fabricated by selective area epitaxy. Single-lateral-mode powers of 200 mW were achieved.

Front Matter: Volume 6456

This PDF file contains the front matter associated with SPIE Proceedings Volume 6456, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

650-mW single lateral mode power from tapered and flared buried ridge laser

Very high single lateral mode output powers of 650 mW are obtained from a diode laser with a unique waveguide design. The waveguide flares in the lateral dimension to create a larger spot size on the facet and simultaneously tapers in the transverse dimension to inhibit propagation of higher order lateral modes. These GaAs buried ridge devices are fabricated by selective area epitaxy.

High power single lateral mode buried ridge laser incorporating a curved waveguide for spatial filtering

We have demonstrated that the use of a curved waveguide in an index guided laser can suppress the onset of higher order modes, while having minimal impact on the device performance. While the concept has been demonstrated here in a buried ridge laser fabricated by selective area epitaxy, it applies generally to all types of single lateral mode index guided lasers.

Front Matter: Volume 6876

This PDF file contains the front matter associated with SPIE Proceedings Volume 6876, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

Heat Treating and Cladding Operations with High-Power Diode Lasers

As tools for use in industrial applications, High Power Direct Diode Lasers [HPDDL], also known as semiconductor lasers, are becoming more prevalent as a heat source for industrial applications. Diode laser technology has now been used in production for a number of years. Their unique beam shape, low ownership cost, high efficiency (~60%), and compact design make them an economic alternative to traditional heat technologies for heat treating and cladding of overlay operations. The benefits of using HPDL for laser surface transformation hardening and cladding are discussed.