Precision openings for construction of an optical backplane have been machined in an optical fiber using an excimer laser operating at a wavelength of 193 nm. The openings were made by imaging the laser beam onto the polymer fiber cladding with a telescope, then ablating the cladding with a sufficient number of pulses to expose the core.Circular openings measuring 250 and 625 microns and elliptical openings measuring 650 x 350 microns have been made in the cladding of a 1 mm polymer-clad silica fiber. Examination by scanning electron microscopy reveals that the best quality openings are obtained with either the smaller circular geometry or the elliptical geometry. For various reasons, elliptical openings, with the major axis oriented along the longitudinal axis of the fiber, appear more suitable for tap construction.Individual optical fiber taps have been constructed by attaching a tap fiber to a laser machined opening in a central fiber using a ultraviolet-curable acralate. Individual tap measurements were made on the elliptical and the 250 micron circular openings. In addition, a triple tap assembly was made using elliptical tap openings. These results indicate that the excimer laser machining technique may be applicable to the construction of a linear tapped bus for optical backplanes.

A method for repairing transparent defects in photomasks has been developed. We discuss the experimental development and integration of the process into a commercial repair system. The defect repair process makes use of a laser to initiate thermal decomposition of a modified commercially available gold metallorganic ink.The ink is locally decomposed with a laser over the defect thereby forming an adherent opaque gold repair pad over the defect. Rectangular repair pads from lum to 25um on a side can be deposited with a single laser exposure of 5 seconds.

Large core high NA glass fibers are often used to distribute the energy in high-power laser material processing systems. It is important to understand mode propagation in these fibers so that laser material processing systems can be designed with the minimal size optics and still have acceptable working distances and delivery efficiencies. The fundamental challenge in this respect is to understand mode propagation in these specialty fibers. The experiments summarized here confirmed that optics much smaller than optics designed through worst-case analysis are effective in practical delivery configurations.

An excimer laser technique was developed to machine precision tap openings in a polymer-clad silica optical fiber for use in the construction of an optical backplane. In this technique, a telescope was used to image the laser beam onto the surface of the fiber at the desired tap location. The cladding then was removed using a prescribed number of pulses from the excimer laser. Single optical fiber taps were constructed using an ultraviolet-curable acralate to attach a tap fiber to a laser-machined opening in a central fiber. Tap measurements were made on single taps constructed from 650 × 350 micron elliptical openings and 250 micron diameter circular openings. Tap measurements also were made on a triple tap assembly which was fabricated using elliptical tap openings. The elliptical openings, with the major axis oriented along the longitudinal axis of the fiber, were determined to be more suitable for tap construction. The results of this study indicate that excimer laser machining is a promising technique for construction of a linear tapped bus for optical backplanes.

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