US 4,790,619 AGranted

Apparatus comprising Raman-active optical fiber

AssigneeAmerican Telephone and Telegraph Company, AT&T Bell Laboratories

InventorsMalcolm E. Lines, Kenneth B. Lyons, Anne E. Miller, Kurt Nassau

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Abstract

Raman-active optical fiber having very large Raman cross section is disclosed. The fiber comprises glass that has two major components, a glass-forming first component (GeO.sub.2, SiO.sub.2, AsO.sub.1.5, or combinations thereof) and a heavy metal oxide second component (PbO, BiO.sub.1.5, SbO.sub.1.5, TlO.sub.0.5, or combinations thereof), with the first and second major components making up at least 70 mol %, preferably at least 90 mol %, of the glass. The maximum relative Raman cross section .sigma..sub.r of the inventive glass is at least 15, preferably greater than 20, where .sigma..sub.r =.sigma..sub.RA /.theta..sub.SiO.sbsb.2, and where .sigma..sub.RA and .sigma..sub.SiO.sbsb.2 are the maximum 0.degree. K. Raman cross sections of the inventive glass and of pure vitreous SiO.sub.2, respectively. Fiber according to the invention can advantageously be used in apparatus such as optical fiber communications systems, information processing systems that contain an optical fiber memory loop, and optical fiber sensors.

Claims12

Dependent claims

Apparatus comprising

(a) a source of electromagnetic signal radiation;
(b) optical fiber means forming a transmission path for the signal radiation from a first fiber location to a second fiber location;
(c) means for coupling the signal radiation into the fiber at the first fiber location, and signal radiation-responsive means at the second fiber location;
and
(d) signal radiation Raman amplification means comprising a length of a Raman-active optical fiber that forms part of the transmission path for the signal radiation, the Raman-active optical fiber comprising a core and a cladding surrounding the core;
characterized in that
at least the core of the Raman-active optical fiber consists of glass comprising
(e) a glass-forming first major component selected from the group consisting of GeO.sub.2, SiO.sub.2, AsO.sub.1.5, and combinations thereof;
and
(f) a heavy metal oxide second major component selected from the group consisting of PbO, BiO.sub.1.5, SbO.sub.1.5, TlO.sub.0.5, and combinations thereof;
and
further characterized in that
the relative Raman cross section for the signal radiation in the Raman-active optical fiber is at least 15;
and
(h) the first and second major components together are at least 70 mol% of at least the core.

12 more elements

Dependencies are inferred from the claim text.