Maryland's Defense Patent Database

The defense community in Maryland is an R&D powerhouse. Use this database to see the innovative patents that are poised for commercialization.

Data is provided by DoD Naval labs in Southern Maryland. Database funding supported by the DoD Office of Economic Adjustment through a Defense Industry Adjustment grant program.

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Method for producing core/clad glass optical fiber preforms using hot isostatic pressing

Patent Number: 5,735,927

AbstractCore/clad glass optical fiber preforms free of bubbles and soot at the coclad interface are fabricated by inserting a glass core rod into a cladding glass tube sized so that space remains between them, sealing the top and bottom of the tube onto the core rod to form a sealed space between them which is relatively soot free and under a vacuum and then hot isostatically pressing the sealed composite to collapse the tube onto the rod and also collapse bubbles in the glass. Soot formation is avoided or minimized by purging the space with inert gas while the bottom of the tube is collapsed onto the rod and by sealing the top under a dynamic vacuum and at the lowest possible temperature to avoid soot formation without cracking the glass. The space is vacuum outgassed before the second seal is made. Chalcogenide fiber drawn from a preform made in this fashion exhibits very low transmission losses.
Patent Number5,735,927 Issue Date1998-04-07 Link USPTO website

Primary Category

Biographical Information


  • Jasbinder Sanghera, Greenbelt, MD
  • Pablo Pureza, Burke, VA
  • Ishwar Aggarwal, Fairfax, VA
  • Robert Miklos, LaPlata, MD


  • The United States of America as represented by the Secretary of the Navy

Executive Summary

This patent was granted in 1 year, 283 days, which is a faster than average speed.

It has 16 claims, which is fewer than average for this category.

Its proximity to basic research is much less than others in this category, and it displays a much slower than average technology cycle time.

This patent received far fewer citations from other patents, and references far fewer other patents, as compared to other patents in this category.

Grant Time

1 year, 283 days



Patent Grant Time

This patent had a faster than average grant time compared to others in this category.

Patent grant time can be influenced by many factors. Activities within the USPTO that are beyond the control of patent attornies can influence grant time, but short grant times can also indicate well-written patents and dedicated efforts to respond rapidly to USPTO office actions with strong arguments. Shorter grant times are preferable, and the scores for this section are inverse measures — higher scores are better.

Patent Claims

This patent has fewer claims compared to others in this category.

The number of claims in a patent is correlated with its strength. Because greater claim counts increase the cost of a patent, more claims can indicate the importance an applicant assigns to a patent. Importantly, some may elect to file claims across multiple patents. A higher score in this metric indicates more claims, relative to others in this category.

Citations From Other Patents

This patent has received far fewer citations from other patents, than others in this category.

Citations from other patents are an important measure of the significance of a patent. More citations indicate that other technologies build on a patent. Higher scores in this metric are better, and indicate more citations from other patents.

Citations to Other Patents

This patent referenced many more citations to other patents, than others in this category.

A lower number of citations to other patents can be a sign of diminished patent strength. More citations indicate dependence on more other technologies. Higher scores in this category are better, and indicate fewer citations to other patents.

Research and Innovation Indicators
These are percentile ranks — they indicate the percentage of peers with lower scores.

Proximity to Basic Research



This patent has much less proximity to basic research compared to others in this category.

Proximity to basic research is measured by comparing the number of citations to non-patent literature among a cohort of patents. Because most non-patent citations are primary research papers, a higher count indicates greater proximity to basic research.