Long wavelength optical fiber communication and sensing systems
AssigneeAmerican Telephone and Telegraph Company, AT&T Bell Laboratories
InventorsMatthijs M. Broer, Kenneth L. Walker
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Abstract
Optical communication and sensing systems are disclosed which operate at long wavelengths, i.e., wavelengths greater than about 2 .mu.m, but less than or equal to about 11 .mu.m. Each of these systems includes an optical fiber having material, such as a metal halide glass, which is substantially transparent to long wavelength electromagnetic radiation. These optical fibers exhibit reduced microdeformation and macrobending losses, as well as low total dispersions, at the long wavelengths. In contrast to currently held beliefs, this is achieved by using fiber designs involving relatively small relative refractive index differences, which are readily manufacturable and which avoid undesirable crystallization at core-cladding interfaces.
Claims34
A waveguide, comprising:
- an optical fiber which is capable of transmitting electromagnetic radiation of wavelength, .lambda., greater than about 2 .mu.m but less than or equal to about 11.mu.m, said fiber being single mode and characterized by an equivalent step index, relative refractive index difference, .DELTA..sub.e, at said wavelength, .lambda., characterized in that
- said optical fiber includes material which is substantially transparent to said electromangetic radiation of wavelength .lambda., said .DELTA..sub.e is chosen so that ##EQU10## and .DELTA..sub.e .gtoreq.0.391.times.10.sup.-4 .lambda..sup.2 -0.487.times.10.sup.-3 .lambda.+0.411.times.10.sup.-2, and said fiber is dispersion shifted so that the total dispersion suffered by said electromagnetic radiation of wavelength .lambda. within said fiber is less than or equal to about 10 ps/km-nm.
An optical system, comprising:
- a source of electromagnetic radiation, said source being capable of emitting electromagnetic radiation of wavelength, .lambda., greater than about 2 .mu.m but less than or equal to about 11 .mu.m;
- a device;
- and
- an optical fiber which transmits at least a portion of the electromagnetic radiation emitted by said source toward said device, said fiber being single mode and characterized by an equivalent, step index, relative refractive index difference, .DELTA..sub.e, at said wavelength, .lambda., characterized in that
- said optical fiber includes material which is substantially transparent to said electromagnetic radiation of wavelength .lambda., said .DELTA..sub.e is chosen so that ##EQU13## and
- .DELTA..sub.e .gtoreq.0.391.times.10.sup.-4 .lambda..sup.2 -0.487.times.10.sup.-3 .lambda.+0.411.times.10.sup.-2,
- and said fiber is dispersion shifted so that the total dispersion suffered by said electromagnetic radiation of wavelength .lambda.within said fiber is less than or equal to about 10 ps/km-nm.
Dependencies are inferred from the claim text.