Water-free process makes high-bandwidth fiber

May 14, 2001
Researchers at Lucent Technologies (Murray Hill, NJ, and Norcross, GA), Rutgers University (New Brunswick, NJ), and the Massachusetts Institute of Technology (Cambridge, MA) have experimentally clarified the physics of the contamination process involved in making fused-silica optical fibers, and used their results to make dry fiber that lacks the usual absorption peaks.

Fused-silica optical fibers are hindered from reaching their theoretical clarity limit by the very process used to make them, which contaminates them with water. The resulting OH absorption peaksnotably one at slightly shorter than 1400 nmlimit the fiber`s bandwidth and, thus, the number of WDM channels that can be transmitted. Researchers at Lucent Technologies (Murray Hill, NJ, and Norcross, GA), Rutgers University (New Brunswick, NJ), and the Massachusetts Institute of Technology (Cambridge, MA) have experimentally clarified the physics of the contamination process and used their results to make dry fiber that lacks the usual absorption peaks.

Following standard methods, the researchers created a fiber preform by coating the inside of a fused-silica tube with ultrapure glass and collapsing it using a torch that burned hydrogen with oxygen. Rather than drawing the preform into a fiber, the researchers cut and polished a slice of the preform and probed it with a 0.5-mm-diameter beam of light, observing the strength of an OH absorption line occurring at 2.72 µm. They found that OH produced by the torch passed through the cladding of the preform and infiltrated its core at significant concentrations.

Based on this discovery, the researchers have developed a manufacturing process that uses a dry heat source such as an oxygen plasma torch. The process has been used to make dry fiber that transmits at low loss in the 1400-nm region. Lucent has demonstrated simultaneous low-loss transmission of signals over this fiber at 1310, 1400, and 1550 nm. An impediment to wide use of this fiber is the current lack of EDFAs that perform in the 1400-nm region.

About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

Sponsored Recommendations

Brain Computer Interface (BCI) electrode manufacturing

Jan. 31, 2025
Learn how an industry-leading Brain Computer Interface Electrode (BCI) manufacturer used precision laser micromachining to produce high-density neural microelectrode arrays.

Electro-Optic Sensor and System Performance Verification with Motion Systems

Jan. 31, 2025
To learn how to use motion control equipment for electro-optic sensor testing, click here to read our whitepaper!

How nanopositioning helped achieve fusion ignition

Jan. 31, 2025
In December 2022, the Lawrence Livermore National Laboratory's National Ignition Facility (NIF) achieved fusion ignition. Learn how Aerotech nanopositioning contributed to this...

Nanometer Scale Industrial Automation for Optical Device Manufacturing

Jan. 31, 2025
In optical device manufacturing, choosing automation technologies at the R&D level that are also suitable for production environments is critical to bringing new devices to market...

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!